Climate & timing — your questions answered

Before mid-August: autumn lettuce (Winter Density, Marvel of Four Seasons), salad rocket, mizuna, mustards, oriental greens (pak choi, tatsoi), Swiss chard, perpetual spinach, autumn spinach, spring onions, coriander, turnips, land cress and lamb's lettuce. After 25 August: spring cabbage (April, Pixie, Greyhound), winter lettuce and overwintering spring onions. Sow green manures (crimson clover, Italian ryegrass, winter tares, field beans) on bare beds.

Sow spring cabbage in modules or a seedbed after 25 August for transplanting in late September and cropping the following April-May. Earlier sowings risk plants becoming too large before winter and bolting in spring; later sowings (after mid-September) struggle to establish. Reliable varieties: April, Pixie, Greyhound, Wheelers Imperial. This is one of Charles Dowding's most precise UK timing windows — within a week either side of 25 August.

Harvest lavender in August when about half the flowers on each spike are open — the oil content peaks just before full bloom. Cut whole stems with secateurs early in the morning after the dew has dried, bundle in elastic bands (string slackens as stems dry), and hang upside-down in a dry airy shed for 2-3 weeks. Trim the plant back lightly after harvest, but never cut into old woody growth — lavender does not regenerate from old wood.

August tasks: (1) pick tomatoes, beans, sweetcorn, plums and soft fruit daily, (2) sow autumn salads and oriental greens before mid-month, spring cabbage after 25 August, (3) take softwood cuttings of herbs and shrubs, (4) harvest and dry lavender, (5) lift onions, shallots and main-crop potatoes, (6) order autumn garlic and spring bulbs, (7) water consistently to prevent blossom-end rot, (8) watch for cabbage white caterpillars and blight.

Lift onions and shallots once the tops yellow and fall over naturally — typically late July to early August. Choose a dry sunny day, fork up gently, and lay the bulbs to cure on a wire rack or in an airy shed for 2-3 weeks before trimming and storing. Onions that go into store with green necks rot; properly cured onions with paper-dry necks keep through winter. Lift before late August even if tops are still standing — wet weather rots stored onions.

That is powdery mildew (Sphaerotheca fuliginea or Erysiphe cichoracearum) — almost universal on UK courgettes from mid-July onwards, especially on dry-stressed plants. Cultural defences: water at the base never on the leaves, water deeply twice a week, mulch heavily, remove worst-affected leaves and bin (do not compost). A milk-and-water spray (1:9) on remaining leaves slows spread. Full UK fix in our powdery mildew guide.

Yes — August is the last realistic planting window for strawberries to crop next year. Plant rooted runners pegged from your existing bed in June, or fresh certified runners from Marshalls, Suttons or D.T. Brown. Plant into well-prepared soil with compost added, water in thoroughly, and remove flowers for the first six weeks to let the plant establish. The bed will crop in June-July next year and continue for 3-4 years before needing renewal.

Add your postcode to Growli and the app fires the spring cabbage sowing reminder on or after 25 August, schedules the autumn salad sowing window around your local climate, reminds you to lift onions on the first dry day after the tops fall, alerts on BlightSpy confirmed cases, and pre-orders prompts for autumn garlic before national stock-out in early September. The app also tracks your lavender harvest window so you cut at peak oil.

August is the main fall-garden planting month. Cold zones 3-5 direct-sow lettuce, spinach, arugula, fall radishes, salad turnips, fall carrots (60-day varieties) and transplant broccoli, cauliflower, cabbage, Brussels sprouts and kale early in the month. Mid zones 6-7 add a wider fall window with peas, beets, kohlrabi, Swiss chard, fall carrots and Asian greens. Warm zones 8-10 start fall tomatoes and peppers from transplant, with late-August salad and bean sowings.

Order garlic from July through August. The best cultivars sell out by September from specialty suppliers (Filaree Garlic Farm, Hood River Garlic, GroEat). Plant softneck (Silverskin, Inchelium Red, California Early) in zones 7+ and hardneck (Music, German White, Chesnok Red, German Extra Hardy) in zones 3-7. Plant cloves 4-6 weeks before your first hard freeze: zone 3 in late September, zone 5 in mid-October, zone 7 in late October, zone 8+ in November.

Only in warm zones 8-10 for a fall crop. Set heat-set transplant varieties (Heatmaster, Phoenix, Solar Fire, Florida 91, Tropic) in shade for the first 3-4 days, water daily for 10 days, and protect from the worst afternoon sun with shade cloth. Cold and mid zones cannot start tomatoes in August — the fruit will not ripen before frost. In zones 3-7, focus on cool-season fall crops instead.

Aerate and overseed cool-season lawns (Kentucky bluegrass, tall fescue, perennial ryegrass) in zones 5-7 from mid-August through mid-September. Soil is still warm enough for fast germination but air temperatures have dropped enough to reduce disease pressure. Core-aerate first, drop seed at the bag rate, top-dress lightly with compost, and water daily for 14 days. Warm-season lawns (Bermuda, zoysia, St. Augustine) are renovated in late spring, not fall.

Take 4-6 in semi-ripe cuttings from non-flowering shoots. Strip the lower leaves, dip the cut end in rooting hormone, and insert into a 50/50 mix of perlite and peat or coir. Cover with a humidity dome or clear bag, set in bright indirect light, and keep moist but not soggy. Most perennials root in 2-6 weeks. Fuchsia, pelargonium, salvia, lavender, rosemary, sage, hydrangea, fuchsia and coleus all root readily from August cuttings.

Most likely cabbage white butterflies and cabbage loopers. Adult butterflies lay yellow rocket-shaped eggs on the undersides of brassica leaves; the green caterpillars defoliate plants in days. Cover transplants with insect mesh (Reemay, Agribon AG-15 or similar) from transplant day until harvest, or check undersides weekly and rub off eggs with a thumb. Bt (Bacillus thuringiensis) sprays are a targeted backup.

Three signs together: (1) the tendril nearest the fruit dries up and turns brown, (2) the ground spot turns from white to creamy yellow, and (3) the rind dulls and a thump produces a deep hollow sound rather than a metallic ping. Cantaloupe slips from the vine when ripe — no cutting needed. Honeydew turns creamy white with no green tint. Always check three signs at once; one signal alone can mislead.

Add your ZIP to Growli and the app counts back from your average first fall frost so every August reminder fires on the exact right day for your zone — fall brassica transplant day, the cutoff for warm-season sowing, garlic ordering, cool-season lawn aeration window and the start of fall garlic order shipping. The app also tracks daily watering needs for fall transplants and flags late blight and squash bug egg-crush windows.

When soil temperature in the top inch reaches about 13°C / 55°F and is rising, sustained for 3 to 5 consecutive days — Penn State Extension advises applying roughly 10 to 14 days before expected germination. By US region that is typically late February to March in the Deep South, March to early April in the mid-South, early April to early May in the mid-latitudes, and late April to early June in the north. The classic cue: apply before forsythia finishes blooming. Local soil temperature always overrides the calendar.

The three common home-lawn actives are dithiopyr (Dimension), pendimethalin (Scotts Halts), and prodiamine (Barricade). Dithiopyr has the widest effective window because it also has early post-emergent activity on just-germinated crabgrass. Prodiamine has the longest soil residual. Pendimethalin is the most widely stocked at big-box stores. All are granular, applied with a spreader, and must be watered in within a couple of days. Always follow the product label and confirm it is approved for lawn use in your country.

Partially. Corn gluten meal is the main organic preemergent — a maize-milling by-product that inhibits germinating-seed roots and adds about 9 to 10% nitrogen. Independent trials typically show it around 60% effective, and only with consistent yearly use over several seasons as the soil seed bank declines. It needs the same preemergent timing and, like synthetic preemergents, also suppresses desirable grass seed, so it cannot be combined with spring overseeding.

Use a selective post-emergent that spares cool-season turf. Quinclorac is the standard choice — it kills crabgrass without harming established ryegrass, fescue, or Kentucky bluegrass at labelled rates, and works best on young plants. Mature multi-tiller crabgrass needs higher rates or repeat treatment. Hand-pulling works for small infestations if you remove the whole plant before it sets seed. Follow all herbicide-label safety and country-approval rules.

No — not with a conventional preemergent. Preemergent herbicides form a soil barrier that blocks all germinating seed, including the grass seed you sow. If you overseed in spring, skip the preemergent on those areas that season. This conflict is a major reason cool-season lawns are best overseeded in autumn, when no preemergent is in play. Siduron is an unusual exception: a preemergent labelled as safe to use at seeding time.

Each crabgrass plant sets thousands of seeds before frost kills it, building a soil seed bank that germinates the next spring. Killing this year's plants without stopping next year's germination changes nothing. The durable fix is density: mow high to shade the soil, overseed in autumn and feed correctly to close bare gaps, water deeply and infrequently, and reseed the thin edges and worn strips where crabgrass establishes first.

Rarely. True crabgrass (Digitaria) is uncommon in the UK because British summers are generally too cool for it, so dedicated preemergents are not a standard UK product. UK lawns instead deal with annual meadow-grass (Poa annua) and Yorkshire fog as the functional equivalents. The UK approach is cultural — scarify out weak coarse grass, overseed and feed for density, mow correctly — since selective grassy-weed herbicides are largely unavailable to UK home gardeners.

Add your zip code to Growli and the app tracks local soil temperature and sends an alert when the crabgrass preemergent window opens — the single most timing-sensitive task in the lawn year — plus a reminder to water the product in. It also flags the spring preemergent versus overseeding conflict. Photograph a suspect weed and Growli helps confirm whether it is crabgrass, annual meadow-grass, or another species before you treat.

Cut a small wedge of turf and measure the spongy brown layer between green growth and soil. Under 1.25 cm / 0.5 inch is beneficial — leave it. 1.25 to 2 cm needs only a light rake. Over 2 cm / 0.75 inch clearly justifies dethatching. The RHS field test: if you cannot see soil when you part the grass blades, the lawn would benefit from scarifying. A lawn that feels spongy underfoot and sheds water rather than absorbing it is also a sign.

Cool-season lawns (all UK lawns, US zones 3 to 7): deep dethatch in early autumn (September across most of the cool-season belt, late August in the Upper Midwest), with an optional light spring rake. Warm-season lawns (US zones 8+): late spring to early summer after the lawn has fully greened up. The lawn needs about 45 days of good growth afterwards to recover, which is what sets the timing.

Yes, if done at the wrong time or too aggressively. Dethatching a dormant or just-greening lawn, scalping with an over-deep machine setting, or dethatching when there is under 0.5 inch of beneficial thatch all damage healthy turf. The most common serious mistake is dethatching and core-aerating in the same session — that combined stress can set a lawn back an entire season. Always start shallow and make a second pass only if needed.

Do not do both in the same session — the combined stress is too much. If a lawn needs both, do them in separate years, or space them by at least several days within the same recovery season. As a rule of thumb: aerate when the main problem is compaction (water pools, soil is hard); dethatch when the problem is a thick spongy organic mat. Both pair well with autumn overseeding for cool-season lawns.

They are essentially the same operation under different regional names — dethatching is the US term, scarifying the UK term. Both mechanically rake the dead organic layer out of the lawn. UK scarifying often also targets moss, which is common in cooler, damper conditions. Treat moss with lawn sand or ferrous sulphate before scarifying so you do not just spread its spores.

Over-fertilising with heavy nitrogen, shallow frequent watering, compacted or low-microbe soil, and naturally thatch-prone grasses (Kentucky bluegrass, Bermuda, zoysia thatch faster than ryegrass or tall fescue). Mulched grass clippings do not cause thatch — they are mostly water and decompose within days. Correcting watering and fertiliser habits slows thatch buildup so you dethatch less often.

Usually yes. Aggressive dethatching lifts living runners along with the dead layer and exposes bare soil. Overseeding the thin and bare areas immediately after — while the soil is open and the recovery season is ahead — gives the fastest, densest recovery and crowds out weeds. This is exactly why cool-season dethatching, overseeding, and autumn feeding are best done together in early autumn.

Add your zip code or postcode to Growli and the app sets your dethatching window by grass type and local climate, reminds you to treat moss before scarifying (UK), warns against combining it with aeration in the same week, and prompts the overseed-and-feed follow-up. Photograph a turf wedge and Growli helps judge whether the thatch layer is in the beneficial range or genuinely needs removing.

For cool-season lawns (all UK lawns and US zones 3 to 7), late August to early October is by far the best window — warm soil for fast germination, autumn rain, low weed pressure, and two growth seasons before the next summer stress. Early spring (once soil hits 13°C / 55°F) is a workable backup but second-best. For warm-season lawns (US zones 8 and warmer), overseed seeded grasses like common Bermuda in late spring to early summer after full green-up.

For overseeding (thickening an existing lawn, not bare renovation): tall fescue and perennial ryegrass 4 to 6 lb per 1,000 sq ft, Kentucky bluegrass 1 to 2 lb, fine fescue shade mixes 3 to 4 lb. UK ryegrass/fescue lawn mixes: 25 to 35 g per m². Roughly double these rates for bare-soil renovation. The seed bag label always carries the authoritative rate — coated seeds differ from raw seed.

It helps significantly on compacted or clay soils — core aeration pulls plugs that give seed ideal soil contact and moisture. It is optional on loose, healthy soil. Critically, do not core-aerate and dethatch in the same session: the combination is severely stressful to the lawn. Space them a few days apart, or do one this year and the other next year.

Until germination (roughly days 1 to 14), water lightly 1 to 3 times per day to keep the top few millimetres of soil constantly damp but not waterlogged — newly sown seed has no roots and dies if the surface dries out. After germination, reduce to once daily and water a little longer. From about week 5, taper toward the normal deep-and-infrequent schedule for established turf.

Yes for cool-season lawns, but it is the second-best window. Spring seedlings have only a short period before summer heat, and any spring crabgrass preemergent you apply will also block grass seed from germinating. If you overseed in spring, skip the preemergent on those areas that season. Autumn overseeding establishes far more reliably for cool-season grass.

In good autumn conditions with warm soil and steady moisture, cool-season grass germinates in 5 to 10 days; ryegrass is fastest, Kentucky bluegrass slowest (up to 2 to 3 weeks). The new grass usually reaches first-mow height in 3 to 5 weeks. Keep off the area until it has been mown at least twice, and use a sharp blade on dry grass for that first cut.

Yes — a starter fertiliser high in phosphorus (around 24-25-4 NPK in the US) supports root development on the new seedlings. Avoid combined weed-and-feed products on overseeded areas: the crabgrass preemergent they contain blocks grass-seed germination just as effectively as it blocks weed seed. See the lawn fertilizer schedule for the full feeding calendar.

Add your zip code or postcode to Growli and the app pins your overseeding window from local soil temperature and grass type, sends a soil-temp alert when the window opens, and runs a daily watering reminder schedule through the two-to-four-week establishment period. Photograph thin or bare patches and Growli helps diagnose whether the cause is shade, compaction, disease, or wear before you reseed.

Sow spring cabbage (April, Pixie, Greyhound), autumn lettuce, salad rocket, mizuna, mustards, pak choi, tatsoi, Chinese cabbage, Florence fennel, endive, chicory, spring onions, beetroot, maincrop carrots, Swiss chard, perpetual spinach, turnips, kohlrabi and parsley. Bush French beans for September picking in the south. Plant out leeks, winter brassicas (Brussels sprouts, sprouting broccoli, winter cabbage, kale) from May sowings if not already done.

July tasks: (1) pick beans, peas, courgettes and soft fruit every 2-3 days, (2) pinch tomato side shoots weekly and stop the plants at 5-7 trusses set, (3) water deeply 1-2 times a week not lightly every day, (4) sow autumn salads and spring cabbage, (5) lift garlic, onions and shallots, (6) check BlightSpy for tomato blight risk, (7) take softwood cuttings of herbs and shrubs, (8) deadhead roses and bedding weekly.

Pinch out the growing tip of cordon tomatoes in mid- to late July once the plant has set 5-7 trusses outdoors or 7-8 in a greenhouse. The UK summer is too short for fruit set above the seventh truss to ripen — stopping the plant redirects energy from leaf and bud growth into ripening the existing crop. Bush (determinate) varieties — Tumbling Tom, Roma, Crimson Crush — do not get stopped; let them sprawl and crop naturally.

Tomato blight (Phytophthora infestans) needs warm wet weather. Cultural defences: grow resistant varieties outdoors (Crimson Crush, Mountain Magic, Fantasio), strip lower leaves below the lowest truss to improve airflow, water at the base never the leaves, ventilate greenhouses aggressively, and check BlightSpy (the RHS-supported Fight Against Blight forecast) for confirmed cases in your region. If blight appears, pick all unaffected fruit immediately to ripen indoors.

Outdoor tomatoes need 3-4 litres per established plant twice a week in dry July weather — deep, consistent watering beats daily light sprinkles. Greenhouse pots typically need daily watering once roots fill the pot and temperatures top 22°C. The RHS specifically warns that irregular watering causes blossom-end rot and split fruit. Mulch with grass clippings, compost or straw to even out soil moisture and reduce watering frequency.

Late June to mid-July across most of the UK, mid- to late July in Scotland and Northern Ireland. The signal: the bottom 3-4 leaves have yellowed and dried while the top 5-6 leaves stay green. Each green leaf equals one wrapper layer on the bulb. Dig with a fork rather than pulling, then cure in a dry airy spot for 2-3 weeks before trimming and storing. Full schedule in our when to plant garlic UK guide.

Sow in July for autumn cropping: spring cabbage, autumn lettuce (Winter Density, Marvel of Four Seasons), salad rocket, mizuna, mustards, pak choi, tatsoi, Chinese cabbage, Florence fennel, endive, chicory, spring onions, beetroot, maincrop carrots, Swiss chard, perpetual spinach, turnips, kohlrabi and parsley. The RHS notes that every fortnight of July delay shortens the autumn cropping window by 3-4 weeks because day length drops fast from September.

Add your postcode to Growli and the app times harvest reminders by crop and variety (peas at peak sugar, courgettes before they bolt), schedules watering around the Met Office five-day rain forecast, fires a blight alert if BlightSpy reports confirmed cases in your region, and reminds you to lift garlic when the bottom-leaf yellowing signal is likely. The app also pre-orders prompts for spring bulbs and autumn garlic before national stock-out.

July is fall-garden start month for most of the lower 48. Cold zones 3-5 direct-sow beans, beets, carrots, kohlrabi, fall radishes and start brassicas indoors. Mid zones 6-7 direct-sow beans, beets, carrots, kale, collards, fall radishes and start broccoli/cabbage indoors for August transplant. Warm zones 8-10 start tomato, pepper and eggplant transplants indoors for September fall planting, and direct-sow okra, southern peas and Malabar spinach.

Water deeply (1.5-2 gallons per established plant twice weekly), mulch 2-3 in deep with straw or shredded leaves, and water at soil level only. Expect heat-set failure (fewer new fruit) once daytime highs cross 90 F with nights above 75 F — this is normal and the plant recovers in September. Shade cloth (30-40% shade) over rows in zones 8-10 during peak heat extends production. Pick fruit at first blush of color and ripen indoors to prevent splitting and sunscald.

Most vegetables need 1-2 in of water per week, soaking the top 6-8 in. In zones 8-9 during heat waves, raised beds need watering every 2-3 days and containers daily. Water in the morning so foliage dries before nightfall — evening watering on humid nights drives fungal disease. Use a rain gauge in the bed; a single thunderstorm can drop 1 in in 20 minutes and let you skip the next watering.

Harvest garlic when the bottom 4 leaves have yellowed and dried but the top 4-5 are still green. That typically lands late June in zones 8-9, mid-July in zones 6-7, and late July in zones 4-5. Dig with a fork (do not pull), brush off soil without washing, and cure in a shaded airy spot for 2-3 weeks. Cured bulbs with intact wrappers store 6-9 months for softneck, 4-6 for hardneck.

Most likely squash vine borer. Look for a small hole at the base of the stem with sawdust-like frass nearby. Slit the stem lengthwise with a sharp knife, remove the inch-long white larva, then bury the slit section under soil to encourage adventitious rooting. Prevention next year: wrap stem bases with aluminum foil from June, row-cover plants until female flowers open, and grow resistant Cucurbita moschata species (butternut, tromboncino) instead of pepo squash.

Powdery mildew explodes in warm humid July weather. Cultural prevention is more effective than spray. Water at soil level only (drip or soaker hose), space plants for airflow, prune lower leaves once vines start running, and choose resistant varieties (Marketmore 76, Diva, Tasty Jade cucumbers; Success PM zucchini). Once mildew shows, milk-and-water sprays (1:9 ratio) or potassium bicarbonate slow spread. Remove badly affected leaves and bag for trash.

Count back 6-8 weeks from your average first fall frost plus the days-to-maturity for your variety. For most zones 5-7, that means starting broccoli, cauliflower, cabbage and Brussels sprouts indoors early to mid-July for August transplant. Zone 8-10 gardeners start fall brassicas indoors in August-September because of summer heat. Your state cooperative extension publishes county-specific fall planting calendars.

Add your ZIP to Growli and the app times every July reminder around your specific microclimate — watering escalation during heat waves, harvest windows for tomatoes and corn tied to local degree-days, hornworm and Japanese beetle peak alerts, and fall sowing reminders that count back from your average first frost. The app also reminds you when garlic is ready to lift (4 lower leaves yellow) and when to stop fertilizing trees before fall hardening.

Direct-sow French beans (dwarf and climbing), runner beans, courgettes, marrows, squash, sweetcorn, beetroot, maincrop carrots, salad leaves, lettuce (bolt-resistant), peas (early varieties), Florence fennel, Swiss chard, perpetual spinach, spring onions and radishes. Plant out leeks, winter brassicas (cabbage, sprouting broccoli, kale, Brussels sprouts), celery and celeriac from May indoor sowings. Plant out summer bedding and dahlias if not done in late May.

June tasks split into six jobs: (1) finish planting out tender crops, (2) sow main succession of beans, courgettes and salads, (3) pinch tomato side shoots weekly and feed once flowering, (4) net strawberries before the first berry ripens, (5) water deeply twice a week not lightly every day, and (6) watch for blackfly, slugs, whitefly and cabbage whites. Plus the standing weekly jobs: mow, tie in climbers, deadhead roses, pull broad beans and salad.

Stop cutting asparagus on 21 June, the longest day. The RHS rule is the eight-week rule — cut for eight weeks from the first spear emerging in mid-April, then let the fern grow for the rest of the season. The fern photosynthesises and feeds the crown to build next year's spears. Cut later than 21 June and you weaken the crown; next year's crop will be thinner and the bed life shorter.

Outdoor tomatoes need 2-3 litres per established plant twice a week in dry June weather. Greenhouse tomatoes typically need daily watering once temperatures top 22°C and pots have filled with roots. The RHS specifically warns that irregular watering causes blossom-end rot and split fruit — consistent deep waterings beat light daily sprinkles. Mulch around the base with grass clippings or compost to even out moisture.

Yes — for cordon (indeterminate) varieties only. Pinch out the small shoots that emerge in the V between the main stem and a leaf, when they are 3-5 cm long. Do this weekly; a missed shoot in week one is a second main stem by week three. Bush (determinate) varieties — Tumbling Tom, Roma, Crimson Crush — do not need pinching; let them sprawl. Tie the main stem to its cane every 30 cm of growth.

Black bean aphid (Aphis fabae) colonies build up on tender broad bean tips from late May. The RHS-recommended response is to pinch the growing tip out the moment the first pods set — this redirects energy to the crop and removes the aphids' food source. Squash the few remaining colonies and wait. Ladybird and hoverfly larvae usually clear the rest by mid-June. Avoid spraying — it kills the predators that solve the problem long-term.

Most UK strawberry varieties fruit from late May (south coast and Cornwall) through to early July, with the peak window in mid- to late June. Everbearing varieties (Albion, Mara des Bois) crop in pulses from June to October. Net beds the moment the first berry colours — blackbirds and thrushes strip rows fast. Pick every 2-3 days, lift fruit off the soil with straw or strawberry mats, and remove runners from cropping plants.

Add your postcode to Growli and the app schedules every June reminder around your specific climate — weekly tomato pinch-out and feed, strawberry harvest windows tied to local degree-days, watering reminders that increase during forecast dry spells, and pest watches that align with the BlightSpy forecast for tomato blight in your region. The app also reminds you to net strawberries before the first berry ripens and to stop cutting asparagus on 21 June.

It depends on your zone. Cold zones 3-5 finish tender-crop planting (tomatoes, peppers, beans, squash) and start fall brassicas indoors late June. Mid zones 6-7 succession-sow beans, corn, cucumbers, squash, salads and herbs; sow fall brassicas indoors. Warm zones 8-10 stop cool-season sowing — switch to okra, southern peas, sweet potato, Malabar spinach, peanuts and heat-tolerant melons. Order garlic now for fall planting and start fall transplants under cover.

Yes — for indeterminate (cordon) varieties only. Pinch the small shoots that emerge in the V between main stem and a leaf, when they are 3-5 in long. Do this weekly; a missed shoot in week one becomes a second main stem by week three. Determinate (bush) varieties — Roma, Celebrity, Bush Early Girl, Marglobe — do not need pinching. Let them sprawl naturally and stake the main stem only.

Established in-ground tomatoes need 1.5-2 gallons per plant twice a week in dry June weather. Container tomatoes need daily watering once temps top 80 F and pots have filled with roots. Irregular watering causes blossom-end rot and split fruit — consistent deep waterings beat light daily sprinkles. Mulch the base with straw, shredded leaves or grass clippings to even out soil moisture between waterings.

Japanese beetle adults emerge east of the Mississippi from mid-June through July, tracking soil temperature. Zone 7 (Mid-Atlantic, mid-South) sees first adults mid-June; zone 6 (Ohio Valley, lower Midwest) late June; zone 5 (Chicago, Boston) early July. Hand-pick at dawn into soapy water while they are sluggish. Avoid pheromone traps near the garden — they attract more beetles than they catch. Milky spore and beneficial nematodes target the soil-dwelling grub stage.

Squash vine borer moths fly across the eastern US from late June through July, laying eggs at the base of squash and zucchini stems. The larva tunnels inside the stem and the plant wilts overnight. Prevention beats cure — wrap stems in aluminum foil at the soil line, or cover plants with floating row cover until female flowers open. Choose resistant species (butternut, tromboncino, Cucurbita moschata varieties) over Cucurbita pepo. Once you see frass at the stem, slit the stem lengthwise and remove the larva.

June-bearing varieties fruit for 2-3 weeks in late spring — late April to early June in zones 8-9, mid- to late June in zones 5-7, late June to early July in zones 3-4. Day-neutral and everbearing varieties (Albion, Seascape, Tribute, Tristar) crop in pulses from June through October. Net beds before the first berry colors, tuck straw or mats under fruit, and pick every 2-3 days.

Count back the days-to-maturity from your average first fall frost plus two weeks of harvest window. For most of the lower 48, fall brassica starts begin indoors late June for July transplant, fall carrots and beets direct-sow in July, and fall salads sow August-September. Warm zones 8-10 follow a different calendar — fall planting starts in August-September because of summer heat. Your state cooperative extension publishes a county-specific fall planting calendar.

Add your ZIP to Growli and the app schedules every June reminder around your specific climate — weekly tomato pinch-out and feed reminders, strawberry harvest windows tied to local degree-days, watering reminders that escalate during forecast dry spells, and pest watches that align with your region's Japanese beetle, squash vine borer and hornworm emergence windows. The app also pings you to order garlic before September stock runs out.

Autumn — specifically an early-September feed (the year's key application: recovery, density, and root reserves) and a late-October-to-early-November winteriser feed applied while the grass is still actively growing and before soil drops below about 10°C / 50°F. Plus one light spring feed in late April or May. Autumn feeding builds the lawn because the grass directs energy into roots and reserves rather than soft top growth.

Cool-season lawns (UK and US zones 3 to 7): no. Feeding during summer heat stress causes disease, burn, and soft growth that collapses — skip June through August entirely. Warm-season lawns (US zones 8+): yes, the opposite — feed monthly through summer because that is their peak growing season. The schedule must mirror the grass's active season.

They are the percentage by weight of nitrogen, phosphorus, and potassium. Nitrogen (first number) drives green colour and leaf growth and is the dominant lawn nutrient. Phosphorus (middle) is for roots and establishment — often zero on maintenance products because many US states restrict it by law. Potassium (last) builds stress, drought, and cold tolerance, which is why autumn/winteriser products are higher in potassium.

Yes, in almost all cases. Slow-release nitrogen (slow-release or coated urea, methylene urea, or organic sources) releases over weeks, avoiding the surge-and-crash growth and burn risk of fast soluble nitrogen. Most quality lawn products are at least partly slow-release. Organic options like Milorganite and Espoma are inherently slow-release and very low burn risk, suiting monthly warm-season feeding and gentle cool-season use.

No. Combined weed-and-feed products contain a crabgrass preemergent that blocks all germinating seed, including the grass seed you sow. If you are overseeding, use a straight fertiliser (a starter formula for new seed) and handle weeds separately. This conflict is one reason cool-season lawns are best overseeded in autumn, away from any spring preemergent.

Late nitrogen on warm-season grass (Bermuda, zoysia, St. Augustine) forces tender new growth that has no time to harden before the first frost, causing winter injury. Stop nitrogen feeding by about early September (the exact cut-off shifts with latitude). The cool-season concept of a high-N autumn winteriser does the opposite of what is intended on warm-season turf — never apply one.

UK lawns are cool-season, so feed in spring (April–May, modest) and autumn (September, more important). Popular products include Westland SafeLawn (organic, pet-friendly, with seed), Aftercut, and Miracle-Gro/EverGreen lawn feeds. The RHS recommends a lower-nitrogen, higher-phosphate or potassium feed in autumn on thin or poor soils to strengthen roots for winter. Avoid 4-in-1 weed-and-feed types if you plan to overseed, and confirm current product approvals.

Add your zip code or postcode to Growli and the app builds a fertiliser calendar from your grass type and local climate — the light spring feed, the all-important early-September feed, the autumn winteriser (cool-season), or the late-spring-through-summer monthly schedule (warm-season) — plus a do-not-feed warning during heat stress and a reminder to water granular feed in. Photograph a discoloured patch and Growli helps tell fertiliser burn from disease or deficiency.

About 1 to 1.5 inches (2.5 to 4 cm) per week during active growth, including rainfall, delivered in one or two deep soakings rather than daily light sprinkling. This wets the root zone to roughly 4 to 6 inches deep, then lets the top inch dry before the next watering — the cycle that trains deep, drought-resilient roots. Measure your sprinkler's output with straight-sided tins rather than guessing a timer setting.

Early morning, roughly 5 to 9 AM. Calm air means less evaporation, and blades dry quickly once the sun rises, denying fungal disease the long damp window it needs. Evening and night watering is the worst option — blades stay wet for hours and that is the biggest avoidable cause of lawn fungal disease. Midday is not harmful to the grass but wastes water to evaporation.

Deeply and infrequently — not daily. On clay soil, one deep watering a week is usually enough (apply slowly or cycle-and-soak to avoid runoff). On sandy soil, split the weekly amount into two waterings because it drains too fast to hold a single large dose. Daily light watering is the most common mistake: it keeps roots shallow and the lawn fragile in heat.

For an established cool-season lawn over a year old: usually no. It goes dormant brown but the crown stays alive and greens up within about two weeks of rain or irrigation returning. Repeatedly part-watering a dormant lawn is more stressful than leaving it fully dormant — commit to either irrigating to target or full dormancy. New, recently sown, or overseeded lawns are the exception and must be kept moist within any water restrictions.

Usually not — for cool-season lawns it is almost always drought dormancy, a survival mechanism. Pull a tuft: firm white roots mean it is dormant and will recover; if it pulls out dry and rootless it is dead. Distinguish dormancy (uniform browning across the lawn) from fungal disease (distinct round patches) and dog-urine burn (small spots ringed by lush green) before doing anything.

Among cool-season grasses, tall fescue has the deepest roots and best drought tolerance, with buffalograss also very drought-hardy. Warm-season grasses are genuinely drought-tolerant as a group — Bermuda, zoysia, and St. Augustine established lawns survive most droughts with little or no irrigation. Choosing a drought-tolerant grass for your zone is itself the most effective long-term way to cut lawn watering.

Rarely for established lawns — the UK's temperate, generally wet climate usually meets demand from rainfall alone. Supplement only during prolonged hot dry spells, and only where legal: during a hosepipe ban, watering an established lawn with a hose is prohibited, and the correct response is to let the lawn go dormant (it recovers fully when rain returns). New and overseeded lawns are the exception.

Add your zip code or postcode to Growli and the app builds a deep-and-infrequent watering schedule from your grass type, soil type, and local weather — splitting it correctly for sandy versus clay soil, telling you when rain has covered the week, and signalling when an established cool-season lawn should simply be allowed to go dormant rather than rescue-watered. Photograph a browning area and Growli helps tell drought dormancy from disease.

In May you can plant out tomatoes, courgettes, marrows, squash, French beans, runner beans, sweetcorn, peppers (under cover), aubergines and basil after the last frost. Direct-sow lettuce, radishes, beetroot, carrots, peas, spring onions, parsnips, chard, spinach and turnips. Plant out dahlia tubers, bedding plants, sweet peas and cannas. Sow winter brassicas (cabbage, kale, sprouting broccoli) for summer transplanting.

Mid-May in southern England and Wales, late May in the Midlands and northern England, early June in Scotland and Northern Ireland. The RHS rule is to wait until night-time temperatures have stopped dipping below around 7°C. Always check the Met Office 10-day forecast before committing tender plants — a single clear May night below 2°C will kill seedlings. In Cornwall and the Channel Islands you can plant from early May.

Yes — most of the cool-season vegetables sow directly into warm May soil. Carrots, beetroot, lettuce, radishes, peas, parsnips, chard, spinach, turnips and spring onions all germinate well from May sowings. From mid- to late May (once soil is 12°C+) you can also direct-sow French beans, runner beans, courgettes and sweetcorn. Soil temperature at 10 cm depth is more reliable than air temperature — buy an inexpensive soil thermometer.

May tasks split into five jobs: (1) plant out tender crops raised indoors after frost risk passes, (2) direct-sow cool-season vegetables into warm soil, (3) harden off everything before transplanting, (4) watch for slugs, aphids and late frost, and (5) feed and stake fast-growing perennials. Mow the lawn weekly, pinch broad bean tops once pods set, and net strawberries against birds. Order brassica plug plants and strawberry runners for June.

South coast and Cornwall: mid-April average; southern England and Wales: late April; Midlands and northern England: early to mid-May; Scotland and Northern Ireland: mid- to late May. The Met Office notes that late cold snaps from Scandinavian or Russian air masses remain a threat through May across most of the UK. Cornwall, south Devon and the Channel Islands are typically frost-free by mid-April; the Scottish highlands can see frost into early June.

Yes — plant dahlia tubers outdoors after your last frost, which means late May for the south and early June for the Midlands and north. Stake at planting (driving a cane in afterwards risks spearing the tuber). A single late frost will blacken the foliage and set the plant back a fortnight, so cover with fleece on cold clear nights. In Cornwall and the Channel Islands you can plant from late April.

Slugs are at peak pressure in May — overwintered adults find tender new growth. Use the RHS evidence-based hierarchy: cultural methods first (clear hiding places, water in the morning not evening), physical barriers (copper rings, sharp grit), beer traps refreshed twice a week, then biological control (Nemaslug, a nematode drench applied in March, April and May). Avoid metaldehyde slug pellets — they were banned in the UK in 2022. Ferric phosphate pellets are the legal chemical option.

Add your postcode to Growli and the app ties every May planting reminder to your specific last-frost date from Met Office historical data plus the live 10-day forecast. The reminder only fires when night temperatures are reliably above 7°C and the 10-day outlook shows no frost. A cold May pushes your tomato and dahlia planting reminder a fortnight later than the chart says — so you do not lose seedlings to a Bank Holiday cold snap.

It depends on your USDA zone. Cold zones 3-5 finish cool-season crops (peas, lettuce, spinach, brassicas) and plant tender crops (tomatoes, peppers, beans, squash) only after Mother's Day or Memorial Day. Mid zones 6-7 plant tomatoes, peppers, eggplant, basil, beans, cucumbers and squash after May 15. Warm zones 8-10 are already in summer production — focus on heat-tolerant crops (okra, southern peas, sweet potato, peanuts) and stop sowing cool-season crops until the August fall window.

The reliable rule is two weeks after your average last frost date, once nighttime temperatures stay above 50 F. That's typically May 1-10 in zone 7, May 15-20 in zone 6, late May to Memorial Day in zone 5, and early June in zones 3-4. Warm zones 8-10 should have planted in April; mid-May is too late for full-season yields there. Always check the 10-day forecast — a 30 F night will kill seedlings even after the chart date.

The 'plant after Mother's Day' rule is reliable for zones 5-6 in the Upper Midwest and New England, where the second Sunday in May typically lands a week after average last frost. It is too early for zones 3-4 (wait for Memorial Day or early June) and too late for zones 7-9 (those gardeners planted in April). Use your specific zone and ZIP-code frost date, not a national rule, and confirm with the 10-day forecast before committing tender plants.

Once soil at 4 in depth holds steady at 60 F overnight, you can direct-sow bush beans, pole beans, sweet corn, cucumbers, summer squash, zucchini, melons, okra (warm zones), sunflowers, dill and basil. In cold zones early May is still the right window for cool-season crops — peas, spinach, lettuce, radishes, carrots, beets, chard, scallions and turnips. A soil thermometer pushed into the bed first thing in the morning is the most reliable check.

Average last frost dates by zone: zone 3 late May to early June, zone 4 mid- to late May, zone 5 mid-April to mid-May, zone 6 early to mid-April, zone 7 mid-March to mid-April, zone 8 late February to mid-March, zone 9 early February, zone 10 frost-free. Mountain and Great Lakes microclimates can run 2-3 weeks later than the zone average. NOAA and your state cooperative extension publish ZIP-code specific dates — these are more accurate than zone-wide averages.

Slug pressure peaks in May in moist regions (Pacific Northwest, Great Lakes, New England, Mid-Atlantic). Use iron-phosphate baits (Sluggo, Garden Safe) — these are pet- and wildlife-safe per OMRI listing. Beer traps refreshed every 2-3 days work for small infestations. Copper barriers around raised beds repel slugs by mild electrical shock. Water in the morning so beds dry before nightfall, and clear hiding places (boards, pots) within 6 ft of seedlings.

Add your ZIP to Growli and the app ties every May reminder to your specific NOAA-derived average last frost date plus the live 10-day forecast. The tomato reminder only fires when night temperatures are reliably above 50 F and the 10-day outlook shows no frost. A cold May pushes your tomato and dahlia planting date a week later than the chart says — so you do not lose seedlings to a Memorial Day cold snap in the Upper Midwest or a late frost in the Rockies.

October is the UK's main garlic-planting month — softneck Solent Wight in the milder south, hardneck Lautrec Wight in the colder north. Also sow overwintering broad beans (Aquadulce Claudia) in mild regions, plant spring bulbs including tulips from late October, and start the bare-root season for fruit trees, roses and hedging from late October. Container-grown perennials, trees and shrubs can still go in early in the month while the soil is warm.

Lift dahlia tubers after the first hard frost has blackened the foliage — typically late October to early November in the Midlands and north, earlier in Scotland. Cut stems to 15 cm, fork up the tubers carefully, wash off soil, dry them upside-down for a week, then store in barely-damp compost or vermiculite somewhere frost-free. In mild south-west England, Cornwall and the Channel Islands you can instead mulch the crowns in place with a thick dry mulch.

It depends on your region. In the Midlands, northern England, Scotland and Northern Ireland — and anywhere in a cold year — lift and store them, because the soil freezes hard enough to rot the tubers. In mild south-west England, Cornwall, the Channel Islands and sheltered southern gardens, you can leave them in well-drained soil and cover the crowns with a 10-15 cm dry mulch of compost or leaf mould. Lifting is the safer choice on heavy wet clay anywhere.

Collect fallen leaves through October and November — shredding them with the lawnmower speeds rotting. Pack them into a wire-mesh bin or into moistened, loosely-tied black bin bags with a few holes punched in, kept separate from the compost heap because leaves rot by slow fungal action. Leaf mould is a usable rough mulch in about a year and a fine, crumbly soil conditioner and seed-compost ingredient after two years.

October tasks: (1) plant garlic and overwintering broad beans, (2) lift dahlia, canna and gladioli tubers before the first hard frost (or mulch in situ in mild regions), (3) collect fallen leaves for leaf mould, (4) mulch bare beds with compost or leaf mould, (5) cut back collapsed perennials but leave seedheads for birds, (6) give the lawn its last raised-blade cut, (7) net ponds against leaves, (8) order seed catalogues and bare-root trees.

No. Daffodils, crocus, hyacinths and alliums are best in by September but can still go in during early October. Tulips are actually best planted from late October into November — the cold soil suppresses tulip fire (Botrytis tulipae), so October is the ideal start for tulips even though it is the tail end for daffodils. Plant all bulbs in well-drained soil at two to three times their own depth.

Give the lawn its final cut in October on a dry day, with the mower blades raised — never scalp grass going into winter. Longer grass is more resilient to cold, frost and winter wear. If the autumn stays mild and growth continues, a very light high-blade trim into early November is fine, but stop once growth slows and the ground is wet, as mowing soggy turf compacts and damages it.

Add your postcode to Growli and the app ties the dahlia-lift alert to your specific first-hard-frost forecast from Met Office data — so mild-region growers get a mulch-in-place prompt while colder regions get a lift-and-store alert in time. It also fires your regional garlic-planting window, schedules leaf collection and the last lawn cut, reminds you to grease-band fruit trees, and prompts the seed-catalogue order before popular varieties sell out.

Plant garlic 4-6 weeks before your first hard freeze. Zones 3-4 garlic goes in late September to early October (already late by October); zone 5 plants early to mid-October; zone 6 mid- to late October; zone 7 late October to early November; zone 8 November; zones 9-10 plant November-December with refrigerated cloves. Set cloves 2 in deep, 6 in apart, pointed end up. Mulch 4-6 in deep with straw or shredded leaves once soil drops below 50 F.

Shred leaves with a mower to speed decomposition (un-shredded takes 2 years, shredded 12-18 months). Stack in a wire bin or pallet enclosure in shade, wet thoroughly when filling, and leave alone — leaf mould is fungal decomposition, not bacterial like compost, so no turning is needed. Use half-decomposed leaves as bed mulch within months; wait 12-18 months for crumbly black finished leaf mould. Avoid black walnut leaves (juglone toxicity) and herbicide-treated lawn leaves.

Mulch perennials after the first hard frost but before the ground freezes — typically late October in zones 3-5, mid-November in zones 6-7. Mulching too early keeps soil warm and tells plants to keep growing; mulching too late lets frost penetrate the root zone. Use 3-4 in of straw, shredded leaves or wood chips, pulled 2 in back from plant crowns to prevent rot. Strawberry beds get mulched only after the first hard freeze.

Drop the mowing height to 2.5-3 in for the final 2-3 mowings of the season — typically through mid- to late October in zones 5-7, into November in zone 7. Short fall grass reduces snow mold and vole tunneling. The last mow should leave the lawn at about 2.5 in heading into winter. Apply a fall winterizer fertilizer (high potassium, lower nitrogen) by mid-October — this is the most important feed of the year for cool-season grass.

October is mostly a planting-finish month. Cold zones 3-5 sow cover crops (winter rye early October) only. Mid zones 6-7 plant garlic, spring bulbs, overwintering spinach, mache, claytonia under row cover, plus cover crops. Warm zones 8-10 enter peak fall garden window — sow lettuce, spinach, arugula, mustard, kale, collards, fall radishes, salad turnips, peas, beets and carrots, and plant strawberries and bare-root fruit trees.

Before the first hard freeze, typically mid- to late October in zones 3-5, late October to mid-November in zones 6-7, and November in zones 8-9. Shut the indoor valve to outdoor faucets first, then open the outdoor spigot to drain the line. Disconnect, drain and store hoses indoors — water trapped inside expands when frozen and splits the line. Blow out drip-irrigation systems with compressed air.

Both — but for different reasons. Rake leaves off lawns to prevent suffocation and crown rot of cool-season grass; thick leaf layers kill turf. Leave leaves in flower beds and under trees as natural mulch — they shelter overwintering pollinators (bumblebees, swallowtail chrysalides, fireflies) and break down into soil. Mow over leaves stuck on lawn to shred them; the small fragments either feed the soil or can be raked to a leaf mould pile.

Add your ZIP to Growli and the app times your garlic planting reminder to 4-6 weeks before your first hard freeze — not a generic calendar date. Spring bulb planting fires when soil drops below 60 F at 4 in. The lawn winterizer reminder fires mid-October for cool-season lawns and the perennial mulch reminder fires after first hard frost. The app also alerts you to drain hoses before the first freeze and to lift dahlias and cannas once frost blackens the foliage.

Plant spring bulbs now — daffodils, crocus, hyacinths, alliums, scillas and muscari (tulips wait until November). Plant autumn onion sets (Senshyu, Radar, Electric), transplant spring cabbage, and put in spring biennials such as wallflowers and winter pansies. September's warm moist soil is also the best autumn window for planting new perennials, trees and shrubs. In northern England and Scotland the earliest garlic cloves can go in from late September.

Plant daffodil and narcissi bulbs in September while the soil is still warm — they root early and resent late planting more than most spring bulbs. Plant at two to three times the bulb's own depth (roughly 10-15 cm) in well-drained soil or pots, pointed end up, and water in if the soil is dry. Daffodils planted in September establish strong roots before winter and flower reliably the following March.

Lift maincrop potatoes (Maris Piper, King Edward, Desiree, Cara) in September once the haulm has died back, on a dry day, before slug damage worsens and before the first frost. Dry the tubers for a few hours, discard any damaged or green ones, and store the rest in hessian or paper sacks in a cool, dark, frost-free, well-ventilated place. Lifting promptly is the single biggest factor in reducing slug holes in stored potatoes.

September tasks: (1) plant spring bulbs (daffodils, crocus, hyacinths — not tulips), (2) sow overwintering broad beans, winter lettuce under cover and green manures, (3) take pelargonium and tender perennial cuttings before frost, (4) lift maincrop potatoes and harvest apples, pears and squash, (5) scarify, aerate and autumn-feed the lawn, (6) net the pond before leaf fall, (7) order seed garlic and bare-root trees, (8) watch for slugs and codling moth.

Yes, in mild and southern regions. Sow the hardy variety Aquadulce Claudia (RHS Award of Garden Merit) direct from late September to early November for an early-June crop, well ahead of a spring sowing. Cloche the row over winter in colder spots. In the cold north and on heavy waterlogged clay, autumn-sown beans often rot or get frost-killed — wait for a February to March spring sowing there instead.

September is the last reliable window before frost. Pelargoniums (bedding geraniums) are tender and the parent plants are usually lost to the first hard frost, so cuttings taken now and overwintered on a frost-free windowsill are cheap insurance for next year's display. Take 8-10 cm non-flowering shoots, trim below a leaf node, remove the lower leaves, and pot into gritty, free-draining cuttings compost — they root readily without hormone.

Use an autumn lawn feed — a high-potassium, low-nitrogen formula. Autumn feeds strengthen roots and harden the grass for winter without forcing the soft leafy growth a spring/summer high-nitrogen feed produces. Apply after scarifying and aerating, ideally before forecast rain. Never use a spring or summer feed in September: the lush growth it triggers will not harden before frost and invites disease through winter.

Add your postcode to Growli and the app fires the daffodil and spring-bulb planting window for your local soil warmth, alerts you to lift maincrop potatoes on the first dry day before your area's first frost, schedules the pelargonium-cuttings reminder ahead of your forecast first frost from Met Office data, and prompts the seed-garlic order before national stock-out. It also tracks your overwintering broad bean and green-manure sowing windows by region.

Plant garlic 4-6 weeks before your first hard freeze, when soil temperature drops below 50 F at 4 in depth. That typically lands in late September for zones 3-4, early October for zone 5, mid-October for zones 6-7, late October for zone 8, and November for zones 9-10. Hardneck varieties (Music, German White, Chesnok Red) suit zones 3-7; softneck (Silverskin, Inchelium Red, California Early) suits zones 7+ where winters are mild. Set cloves 2 in deep, 6 in apart, pointed end up; mulch 4-6 in deep with straw.

Plant spring bulbs once soil temperature at 4 in drops below 60 F — typically mid-September in cold zones 3-4, late September to October in zones 5-7, and refrigerator-chilled bulbs in late December to January for warm zones 8-10. Tulips need at least 12-16 weeks of cold below 45 F to bloom; daffodils tolerate slightly warmer chilling. In zones 9-10 most gardeners refrigerate bulbs in paper bags from September until December.

Lift summer tubers and corms after the first hard frost blackens the top growth — typically late September to mid-October in zones 3-5, mid-October to mid-November in zones 6-7. In zones 8-10 dahlias often overwinter in the ground with thick mulch. Cut stems to 6 in, fork tubers gently from the soil, knock off loose soil, and cure in a frost-free shed for 1-2 weeks. Store in barely-moist peat, vermiculite or sawdust at 40-50 F with 80% humidity.

In cold zones 3-5 yes — soil drops below 60 F by mid- to late September and tulips need 12-16 weeks of cold to bloom. In mid zones 6-7 wait until October or early November once soil is reliably below 60 F. In warm zones 8-10 do not plant directly — refrigerate the bulbs in a paper bag (away from ripening fruit, which gives off ethylene) for 12-16 weeks, then plant in late December to January for spring bloom.

Cool-season lawns (Kentucky bluegrass, tall fescue, perennial ryegrass) in zones 5-7 overseed from mid-August through mid-September. Soil is still warm enough for fast germination but air temperatures have dropped. Core-aerate first, drop seed at the bag rate (typically 6-8 lbs per 1000 sq ft for fescue), top-dress with 1/4 in compost, water daily for 14 days, then taper. Warm-season lawns (Bermuda, zoysia, St. Augustine) overseed with ryegrass in October for winter color.

Cold zones 3-5 sow spinach, mache, claytonia, winter radishes and cold-tolerant lettuce under row cover early September only. Mid zones 6-7 sow spinach, lettuce, arugula, mustard, mizuna, fall radishes, salad turnips, kohlrabi, Swiss chard, fall carrots (early September only) and beets. Warm zones 8-9 finally open the cool-season window — fall salad, brassicas, peas, beets, carrots, kale, collards, mustard, kohlrabi and radishes.

Some yes, some no. Cut back early-summer perennials that have browned (daylilies, geraniums, hosta foliage after frost). Leave seed heads on coneflower, rudbeckia, sedum, asters and ornamental grasses for winter interest and bird food. Leave hellebores, ferns and evergreen perennials uncut. Wait until late winter to cut grasses — the standing foliage protects the crown and feeds birds through winter.

Add your ZIP to Growli and the app times your garlic planting reminder to 4-6 weeks before your first hard freeze, your spring bulb reminder to when soil drops below 60 F at 4 in, and your lawn overseeding window to mid-August through mid-September. The app also tracks dahlia and canna lift dates after first hard frost and reminds you to clean up disease-prone debris before winter.

Not in the USDA sense — the UK uses per-plant RHS hardiness ratings rather than a regional zone map. What you do need to know is your typical winter minimum temperature (most of mainland UK is between minus 5 and minus 15°C in a cold winter) and your local microclimate (coastal vs. inland, urban vs. rural, sheltered vs. exposed). Knowing those lets you read RHS ratings against your actual conditions.

Most of England and Wales is reliably hardy down to roughly minus 10°C, so plants rated H5 or hardier are safe choices. Plant H4 with a sheltered spot. In Scotland's Central Belt, prefer H6. In the Highlands, H7. In Cornwall and the Isles of Scilly, you can grow H3 plants outdoors year-round.

Roughly, yes — most of mainland UK behaves like USDA zone 7b or 8a in winter terms, with average annual minimums between minus 12 and minus 7°C. But the comparison is imperfect because UK winters are milder and wetter than equivalent USDA zones in North America, and UK summers are cooler. Plants rated for USDA zone 8 dryland conditions do not necessarily thrive in UK zone 8 wet conditions.

H3 plants survive minus 5 to plus 1°C — mild winters only, suited to Cornwall and sheltered coastal microclimates. H4 plants survive minus 10 to minus 5°C — typical of southern and central UK in an average winter. The 5°C step looks small but determines whether a plant survives a typical Birmingham or Manchester winter without protection.

H7 plants tolerate temperatures below minus 20°C. Examples include silver birch (Betula pendula), Scots pine, many alpine perennials, hardy heathers, dwarf willows, mountain ash (rowan), and most native UK wildflowers from upland regions. H7 is the hardiest RHS band and is rarely needed outside Scottish Highlands or very exposed inland sites.

Rosemary is rated H4 by the RHS — hardy to minus 10°C in well-drained soil. Most of southern and central England grows rosemary reliably in the ground. Wet winters are a bigger killer than cold — plant in free-draining soil or raised beds. In northern England and Scotland, treat rosemary as borderline and grow in a pot you can move into a cold greenhouse for winter.

English lavender (Lavandula angustifolia) is rated H5, surviving down to minus 15°C, and is reliably hardy across mainland UK in well-drained soil. French and Spanish lavenders (Lavandula stoechas, Lavandula dentata) are H4 and may struggle in a hard winter outside southern England. As with rosemary, drainage matters more than absolute cold — wet feet kill more lavender than frost.

Add your UK postcode in Growli and the app maps it to the typical winter minimum for your area (using Met Office climate data) plus elevation and coastal effects from your specific location. The plant recommendations then match RHS hardiness ratings to that local profile rather than to a regional average. You get suggestions for plants that suit your actual garden, not just your nearest big city.

Enter your 5-digit ZIP code at planthardiness.ars.usda.gov or use Growli's free zone finder for an instant answer. The tool returns your zone (e.g. 6b), the temperature range it represents, and a list of plants that thrive in your climate. ZIP-based lookups are accurate to within half a zone for most US addresses.

The USDA's Agricultural Research Service revises the map roughly every 10-15 years using new weather data. The current 2023 edition averages annual extreme minimum temperatures from 1991 to 2020 across 13,412 weather stations, with PRISM-based spatial interpolation. The previous 2012 map used 1976-2005 data from 7,983 stations.

Possibly. About half of the United States shifted half a zone warmer in the November 2023 update, mostly in the upper Midwest, Northern Plains, and Northeast. Check your current zone at planthardiness.ars.usda.gov or via Growli's zone finder rather than relying on pre-2023 advice.

Each USDA number is split into half-zones of 5°F. Zone 6a covers an average extreme minimum of -10 to -5°F (-23 to -21°C); zone 6b covers -5 to 0°F (-21 to -18°C). The 5°F gap matters for borderline plants — zone 6b will overwinter many plants that struggle in 6a.

Zone 13b is the warmest, with average extreme minimums of 65 to 70°F (18 to 21°C). It only appears in the U.S. Virgin Islands. Within the continental US, zone 11a in the Florida Keys is the warmest, with average minimums of 40 to 45°F (4 to 7°C).

Zone 1a is the coldest, with average extreme minimums of -60 to -55°F (-51 to -48°C). It only appears in northern Alaska. The coldest zone in the continental US is zone 3a, covering parts of northern Minnesota, Wisconsin, and Maine, with average minimums of -40 to -35°F (-40 to -37°C).

Not directly. Zones describe winter cold, but vegetables like tomatoes, peppers, and squash are annuals killed by the first frost regardless of zone. For vegetable timing, use your last-frost and first-frost dates. See our guide on when to plant tomatoes for a zone-by-zone schedule that uses frost dates rather than zone numbers alone.

No — the UK uses the RHS hardiness rating system (H1a to H7), which rates each plant rather than mapping regions. Most of England and Wales is roughly equivalent to USDA zones 7-8, Scottish highlands to zone 6, and Cornwall to zone 9. See our UK hardiness zones guide for the full conversion.