edible gardening
How to grow garlic — plant to cure, full guide
Grow garlic from clove to cured bulb: hardneck vs softneck, vernalisation, planting depth, scape harvest, the brown-leaf harvest signal, US + UK varieties.
How to grow garlic — plant to cure, hardneck vs softneck
Garlic is the upside-down crop: planted in autumn, asleep through winter, harvested the following summer. This guide is the full grow-out — variety choice, the vernalisation requirement that makes or breaks the bulb, planting depth and spacing, the spring feeding window, the scape harvest, and the curing process that decides whether your garlic lasts a month or most of a year.
If you only need the planting calendar — exact weeks by US zone and UK region — that lives in our dedicated when to plant garlic guide. This article picks up where that one leaves off: what to do for the nine months after the cloves go in.
Garlic reminders that fit your garden: Add your zip code or postcode to Growli and the app times the whole sequence to your local frost date — clove sourcing, planting week, mulch, spring feed, scape snap, and the harvest signal.
Hardneck vs softneck — choose first
The subspecies you grow changes your climate fit, whether you get scapes, and how long the bulbs store.
Hardneck garlic (Allium sativum var. ophioscorodon)
- Best in US zones 3-7 and most of the UK — needs a real cold winter
- Produces an edible scape (curling flower stalk) in early summer — a bonus crop
- Larger, easier-to-peel cloves (typically 4-8 per bulb), stronger flavour
- Stores 4-6 months
- Examples: Music, German Extra Hardy, Chesnok Red, Spanish Roja
Softneck garlic (Allium sativum var. sativum)
- Best in US zones 7-11 and mild southern UK; tolerates milder winters
- No scapes; more cloves per bulb (10-20), milder flavour
- Stores 8-12 months — this is supermarket and braiding garlic
- Examples: Inchelium Red, California Early; in the UK, Solent Wight and Lautrec Wight (both bred and trialled by The Garlic Farm on the Isle of Wight)
In the overlap (US zones 5-7, UK Midlands and south), plant both: hardneck for flavour and scapes, softneck for storage life and braids.
Vernalisation — the science that sets bulb size
Garlic must experience a sustained cold period to differentiate a single clove into a segmented bulb. The requirement is roughly 6-8 weeks below 40°F (4°C) — hardneck needs the full cold period, softneck is less demanding.
Skip the cold (plant too late in spring with no chilling) and the plant grows leaves but never divides — you harvest a single "round" instead of a head of cloves. The appearance of a hardneck scape in early summer is in fact the visible confirmation that vernalisation was met.
This is why fall planting is standard: cloves get the natural winter cold and a head start on roots. In warm zones (9-11) where winters are too mild, growers pre-chill cloves in the refrigerator at about 40°F for 6-8 weeks before a late-winter planting to simulate the missing cold.
Soil and site
- Full sun — 6+ hours direct.
- Loose, free-draining soil with organic matter worked into the top 8 inches. Garlic rots in waterlogged soil; heavy clay needs grit, compost, or a raised bed.
- Near-neutral pH — 6.0-7.0. Check yours with the soil pH guide and lime acidic beds the season before.
- Rotation: don't plant garlic where any allium (onion, leek, shallot, chive) grew in the last 3 years — see companion planting for what does pair well (it deters aphids near roses and carrots).
Planting — step by step
- Source certified seed garlic from a nursery or specialist grower — not supermarket bulbs (often sprout-inhibited and bred for storage, not your climate).
- Split bulbs into cloves on planting day, keeping the papery wrapper on each. Splitting earlier dries them out.
- Plant only the largest cloves — clove size predicts bulb size. Cook the small inner ones.
- Plant pointed end up, flat (root) end down, 2 inches deep in mild zones, 4 inches deep in cold zones (3-5).
- Space 6 inches apart in rows 10-12 inches apart.
- Mulch with 3-4 inches of straw or shredded leaves after the first hard frost. The mulch buffers freeze-thaw heave and suppresses weeds — critical, because garlic competes poorly with weeds.
Spring and summer care
- Spring feed: as growth resumes, garlic is hungry for nitrogen for its leaf phase. Apply a nitrogen-rich feed (blood meal, or a balanced fertiliser) in early spring through to about a month before bulbing. Stop nitrogen once bulbs start to size up.
- Weeding: keep the bed scrupulously weed-free. Garlic's shallow roots lose to weed competition fast.
- Watering: keep soil evenly moist through spring leaf growth and early bulbing — about 1 inch per week if rain is short. Then the key rule: stop watering 2 weeks before harvest so the wrappers cure firm and the bulbs store well. Watering right up to harvest causes stained, split, rot-prone wrappers.
Scapes — the hardneck bonus crop
Hardneck garlic sends up a curling flower stalk (the scape) about 3-4 weeks before bulb harvest, usually early June. Snap or cut scapes off once they curl one full loop (goose-neck shape). Doing so redirects energy into the bulb — research shows removing scapes can lift bulb size by up to about 25%. The scapes themselves are delicious sautéed, in pesto, or grilled. Softneck garlic does not produce scapes.
Harvest
The signal: harvest when the lower 3-4 leaves have yellowed and dried but the upper 5-6 leaves are still green. Each green leaf corresponds to a wrapper layer on the bulb — wait until all leaves brown and the wrappers split and the bulb won't store; harvest too early and the cloves haven't filled.
Loosen the soil with a fork and lift gently — never yank by the stem (it bruises and the neck tears). Don't wash the bulbs; brush off loose soil only.
By region this is roughly late June to mid-July in most US zones 5-7 and across the UK; mid-June in zones 8-9; mid- to late July in Scotland and northern England — the full regional table is in when to plant garlic.
Curing and storage
- Cure for 3-4 weeks somewhere dark, dry, and well-ventilated (a shed, garage, or covered porch out of direct sun). Hang in bunches or lay on racks with airflow all round.
- Garlic is cured when the neck is dry and tight and the outer wrappers are papery.
- Trim roots to about 1/4 inch and cut stems to 1 inch — or leave softneck stems on to braid (the strings of garlic at farmers' markets are braided softneck; hardneck necks are too stiff to braid).
- Store cured bulbs somewhere cool, dark, dry, and airy (50-60°F / 10-15°C). Don't refrigerate seed or eating garlic — cold triggers sprouting. Save your biggest bulbs as next year's seed stock.
Safety: garlic is toxic to dogs and cats
This is a hard flag. All alliums — garlic, onion, leek, chive — are toxic to dogs and cats, listed as toxic by the ASPCA. Garlic is roughly 3-5 times more toxic than onion by weight, and cats are the most susceptible species. The thiosulfate and N-propyl disulfide compounds damage red blood cells and cause Heinz-body hemolytic anaemia. Concentrated forms (powder, dehydrated flakes) are the most dangerous, but raw cloves, scapes, and foliage all count.
Signs may take several days to appear: weakness, pale gums, lethargy, jaundice, dark urine, collapse. Keep cloves, scapes, trimmings, and curing bulbs out of pets' reach, and never use "a little garlic" as a folk remedy for pets. Call ASPCA Poison Control at (888) 426-4435 if ingestion is suspected.
Related articles
- When to plant garlic — the zone-by-zone fall planting calendar
- How to grow onions — its allium cousin, planted in spring
- How to grow chives — the perennial allium for the kitchen bed
- Companion planting — where garlic fits in the rotation and what it protects
- Soil pH guide — keep the garlic bed near neutral
- Frost date calculator — set your fall planting and summer harvest windows
- How to start a vegetable garden — beginner overview with garlic in the rotation
Reviewed and updated by the Growli editorial team. For questions about anything here, open Growli and ask — or email hello@getgrowli.app.
Frequently asked questions
How do you grow garlic step by step?
Buy certified seed garlic, split it into cloves on planting day, and plant the largest cloves pointed end up — 2 inches deep in mild zones, 4 inches in cold zones, 6 inches apart — in fall in full sun and free-draining soil. Mulch after the first hard frost. Feed with nitrogen in early spring, keep the bed weed-free, snap scapes off hardneck types in early summer, stop watering 2 weeks before harvest, then lift when the lower leaves brown and cure for 3-4 weeks.
What is the difference between hardneck and softneck garlic?
Hardneck garlic needs a cold winter, produces an edible scape, has larger easy-peel cloves and stronger flavour, and stores 4-6 months — best for US zones 3-7 and most of the UK. Softneck garlic tolerates milder winters, has no scape, more and smaller cloves, milder flavour, stores 8-12 months, and can be braided — best for US zones 7-11 and southern UK. In the overlap, grow both.
Why does garlic need a cold period (vernalisation)?
Garlic needs roughly 6-8 weeks below 40°F (4°C) to trigger a single clove to differentiate into a segmented bulb. Without that cold, the plant grows leaves but never divides and you harvest a single round instead of a head of cloves. This is why garlic is planted in fall for natural winter cold; in warm zones, cloves are pre-chilled in the fridge for 6-8 weeks before a late-winter planting.
Should I cut garlic scapes off?
Yes, on hardneck garlic. Snap or cut the scape off once it has curled one full loop, about 3-4 weeks before bulb harvest. Removing it redirects energy into the bulb and can increase bulb size by up to about 25%. The scapes are edible and delicious sautéed or made into pesto. Softneck garlic does not produce scapes.
When do you harvest garlic and how do you know it is ready?
Harvest when the lower 3-4 leaves have browned and dried but the upper 5-6 leaves are still green — each green leaf is a wrapper layer protecting the bulb. That is typically late June to mid-July in US zones 5-7 and across the UK. Stop watering 2 weeks before harvest, then lift gently with a fork rather than pulling by the stem.
How do you cure and store garlic?
Cure harvested garlic for 3-4 weeks somewhere dark, dry, and airy, hung in bunches or laid on racks. It is ready when the neck is tight and the wrappers are papery. Trim roots and stems (or braid softneck), then store at 50-60°F somewhere cool, dark, and dry. Don't refrigerate it — cold makes garlic sprout. Hardneck keeps 4-6 months, softneck 8-12 months.
Is garlic toxic to dogs and cats?
Yes — strongly. The ASPCA lists all alliums including garlic as toxic to dogs and cats. Garlic is about 3-5 times more toxic than onion, and the thiosulfate compounds cause Heinz-body hemolytic anaemia by destroying red blood cells. Cats are most susceptible. Signs (weakness, pale gums, dark urine, collapse) can take days to appear. Keep cloves, scapes, and trimmings away from pets and call ASPCA Poison Control at (888) 426-4435 if ingested.
Can I grow garlic from supermarket bulbs?
It is not recommended. Supermarket garlic is often treated with sprout inhibitors, may carry disease, and is usually a variety bred for storage in a different climate than yours. Buy certified seed garlic from a nursery or specialist grower — it is disease-screened and climate-matched, and you can save your biggest home-grown bulbs as next year's seed.
How does Growli help with growing garlic?
Add your zip code or postcode to Growli and it times the full nine-month sequence to your local frost date — when to source seed garlic, your exact planting week, when to mulch, the spring nitrogen feed window, the early-summer scape snap, the stop-watering date, and the brown-leaf harvest signal. Photograph leaf problems and Growli flags allium issues like rust or rot.