How to grow tomatoes — complete US + UK guide

How to grow tomatoes — complete US + UK guide

Tomatoes are the most-grown vegetable in US and UK home gardens — and the one most likely to disappoint a beginner. The two killers: planting too early (frost) and inconsistent watering (blossom end rot, cracking, leaf curl). This guide is the full year-one playbook: seed-starting timing, transplant, training, feeding, and the 5 problems that will probably hit your plants.

Track your tomato plants: Add your variety to Growli and the app sets reminders tied to your local last-frost date — when to start seeds, when to harden off, when to transplant, when to feed.

When to plant tomatoes (by region)

Tomatoes are frost-tender. Transplant outdoors only after your last expected frost date, and remember that the "indoor seed-start" column is six weeks earlier — see our starting seeds indoors guide for the full setup. Approximate dates:

These are averages. Check your USDA zone (or the UK RHS hardiness ratings if you garden in Britain) for precise local timing.

Choose varieties before you choose plants

Two big categories, then several sub-decisions:

Determinate vs indeterminate

• Determinate ("bush" tomatoes) — grow to a set size (~3-4 ft), produce all their fruit in a 2-3 week window, then decline. Good for canning batches and small spaces. Examples: Roma, Celebrity, Bush Early Girl.
• Indeterminate ("vining" tomatoes) — grow continuously, produce fruit from mid-summer until frost, can reach 8 ft. Need staking. Better for fresh-eating supply. Examples: Cherokee Purple, Sungold, Brandywine, San Marzano.

Beginner varieties (US + UK)

• Sungold (orange cherry) — sweetest cherry tomato, indeterminate, easy.
• Sun Sugar — similar to Sungold, slightly more crack-resistant.
• Celebrity — disease-resistant, determinate, reliable medium-sized red.
• Roma — classic paste tomato, determinate.
• Black Cherry — purple cherry, indeterminate, unusual color, easy.
• Gardener's Delight (UK favorite) — small red, prolific, dependable.

Avoid heirlooms in year one — they're often less disease-resistant and demand more from the gardener.

Soil prep

Tomatoes need:

• Full sun — 6+ hours direct, ideally 8+ in cooler climates.
• Well-draining soil with plenty of organic matter. Heavy clay needs amendment with compost.
• Slightly acidic pH — 6.0-6.8 ideal.
• Calcium — prevents blossom end rot. Mix a handful of crushed eggshells or 1 tablespoon agricultural lime into each planting hole.

Container growers: use bagged potting mix, not garden soil. Garden soil compacts in containers and suffocates roots.

Transplant — the right way

1. Harden off indoor-started seedlings over 7-10 days. Set them outside in shade for 1 hour the first day, gradually increasing time and sun exposure.
2. Plant deep. Bury the stem so only the top 2-3 sets of leaves are above soil. Tomato stems form roots wherever buried — deep planting = stronger root system.
3. Space 24-36 inches apart for determinate, 36-48 inches for indeterminate. Plan the rest of the bed alongside them — see our vegetable garden layout guide for spacing and companion planting.
4. Add support immediately — stake or cage at transplant. Adding support later damages roots.
5. Water deeply after planting. Then resume normal schedule.

Watering

The single most important variable in tomato production. The pattern:

• Deep watering 2-3 times per week — not light daily watering.
• At the base, not on leaves — wet leaves invite fungal disease.
• Consistent — inconsistent watering causes blossom end rot and cracking.
• More in heat — over 30°C/86°F, plants need water daily.

Mulch heavily (2-3 inches of straw, grass clippings, or wood chips) to retain soil moisture and stabilize root temperature.

Feeding

See the dedicated guides: when to fertilize tomatoes and what fertilizer for tomatoes.

Summary:

1. Light balanced 10-10-10 at transplant.
2. Switch to high-potassium feed at first flowering.
3. Continue high-K every 1-2 weeks through fruiting.
4. Stop 2 weeks before final harvest.

Pruning and training

Indeterminate varieties

Remove "suckers" — the small shoots that grow in the V between the main stem and side branches. Prune to a single leader for the cleanest growth, or two leaders for higher yields. Tie the main stem to the stake/cage weekly.

Determinate varieties

Don't prune the suckers — determinates set fruit on those side branches. Just stake or cage for support.

Removing lower leaves

Once the plant is 18 inches tall, remove the bottom 6-12 inches of leaves. This:

• Reduces fungal disease transmission from soil splash.
• Improves air circulation.
• Lets you mulch more cleanly.

When to harvest

Pick when the fruit is fully colored but still slightly firm. Fully ripe tomatoes are too soft for picking — they should be picked at "breaker" stage (color change beginning) for storage, or fully red-but-firm for immediate eating.

Indoor ripening: tomatoes ripen on the counter at 18-21°C. Don't refrigerate ripe tomatoes — cold destroys flavor compounds.

The 5 problems you'll probably have

1. Blossom end rot

Black sunken patch on the bottom of fruit. Cause: calcium uptake failure, almost always from inconsistent watering. Fix: mulch + deep regular watering. The eggshell/lime added at planting helps prevent it.

2. Cracking

Concentric cracks around the stem end. Cause: heavy watering after dry spell. Fix: consistent watering, mulch. Pick affected fruit early — they spoil fast.

3. Curling leaves

Lower leaves curl upward. Usually heat stress (resolves overnight) — see why are my plant leaves curling. If new growth comes out twisted, suspect virus or herbicide drift.

4. Yellowing lower leaves

Either overwatering or magnesium deficiency. See our dedicated yellow tomato leaves diagnostic for the Epsom salt fix and the wider yellow plant leaves hub.

5. No fruit set despite flowers

Caused by extreme heat (over 32°C/90°F suppresses pollination) or insufficient pollinators in greenhouses. Outdoors, attract bees with flowers nearby; in greenhouses, gently shake plants daily to release pollen.

How many plants per household

A rough guide:

• 2-3 plants — fresh eating for a couple, summer salads
• 4-6 plants — fresh eating for a family of 4
• 8-12 plants — fresh eating + some sauce-making
• 20+ plants — serious canning and preserving

Indeterminate varieties produce 2-3x the seasonal yield of determinate. Mix one or two of each — our guide to the types of tomatoes breaks down beefsteak, cherry, plum, paste and heirloom so you can pick the right cultivars for fresh eating versus sauce.

Related articles

• When to fertilize tomatoes — the timing schedule
• What fertilizer for tomatoes — product-by-product
• Why are my plant leaves curling? — tomato-specific section
• Why are my plant leaves turning yellow? — magnesium and overwatering
• How to start a vegetable garden — bigger-picture beginner guide
• Find your USDA hardiness zone — type your ZIP or UK postcode to get your zone and frost dates
• Planting calendar — month-by-month sowing and transplant windows for tomatoes and every other crop
• USDA zone & frost-date lookup — for timing transplants

Reviewed and updated by the Growli editorial team. For questions about anything here, open Growli and ask — or email hello@getgrowli.app.