How to Grow Tomatoes in the UK: From Planting Out to Harvest

There's nothing quite like the taste of a homegrown tomato. Whether you're growing in a greenhouse, on a sunny patio, or in raised beds, tomatoes are one of the most rewarding crops you can grow in the UK — as long as you know a few key tricks. This guide covers everything you need to know from planting out through to harvest.

Quick Reference: Key Dates at a Glance

Task	When	Notes
Sow seeds indoors	February – March	Warm windowsill or propagator
Harden off	April – May	1–2 weeks, days outside / nights inside
Plant out (greenhouse)	Late April	Once nights stay above 10°C
Plant out (outdoors)	Late May – early June	After last frost; Midlands typically late May
Start feeding	When first flowers appear	Weekly high-potassium tomato feed
Pinch out growing tip	Late August	Cordon varieties only
Harvest	July – October	Pick regularly to encourage more fruit

Choosing Your Tomato Variety

With hundreds of varieties available, it helps to know what you're looking for before you buy.

Cordon (Indeterminate) vs Bush (Determinate)

• Cordon varieties grow tall and need staking and regular pinching out of side shoots. They tend to produce fruit over a longer season. Great for greenhouses. Examples: Gardener's Delight, Moneymaker, Shirley F1.
• Bush varieties are more compact, need little or no staking, and don't require pinching out. Better suited to containers and outdoor growing. Examples: Tumbling Tom, Red Cherry.

Cherry, Salad or Beefsteak?

• Cherry tomatoes — small, sweet, prolific. Great for beginners and containers. Try Sungold F1 or Suncherry Smile F1 for outstanding flavour.
• Salad tomatoes — medium-sized, versatile. Roma VF is a classic choice.
• Beefsteak tomatoes — large and meaty, best for slicing. Try Supersteak F1 — best grown under glass in the UK.

Our tip for UK gardeners: Cherry varieties like Sungold F1 or Gardener's Delight are the most reliable outdoors. If you want bigger tomatoes, grow them under glass.

Greenhouse vs Outdoor Growing

Growing in a Greenhouse

A greenhouse gives you a longer season, more warmth, and protection from blight. You can plant out from late April and expect fruit from late June onwards. Use a dedicated tomato planter compost for best results in containers or grow bags.

Growing Outdoors

Outdoor tomatoes need a warm, sheltered, south-facing spot. With the right variety and a good summer, you can get an excellent crop. Plant out after the last frost — late May to early June in the Midlands.

When to Plant Tomatoes Outside in the UK

The golden rule: don't rush it. Tomatoes hate frost, so wait until late May to early June before moving plants outside. In the Midlands, that's typically late May. If you're growing in a greenhouse or polytunnel, you can plant out from late April onwards.

Hardening Off: The Step Most Gardeners Skip

Before planting out, spend 1–2 weeks hardening off your plants. Put them outside during the day and bring them back in at night. This acclimatises them to wind, cooler temperatures, and direct sun — skipping this step is one of the most common reasons tomato plants struggle after planting.

Soil, Compost and Container Preparation

In Beds and Borders

Tomatoes do best in rich, well-drained soil. Before planting, dig in plenty of well-rotted compost to improve structure and fertility. Growmoor Multi Purpose with John Innes is a great all-rounder for improving bed soil. Rotate crops each year to reduce disease risk.

In Containers

Use a large container — at least 30–40 litres per plant — filled with a quality compost. Our Growmoor Tomato Planter Compost 56L is specially formulated for tomatoes, or try the GroWorm Black Gold Peat Free Organic Tomato Planter for an organic option.

In Grow Bags

Grow bags are a convenient option, especially in a greenhouse. Our Growmoor 4 Plant Growbag 38L is ideal — it holds four plants and is designed for heavy-cropping vegetables like tomatoes.

Choosing the Right Spot

• Full sun — at least 6–8 hours a day
• Shelter from wind — a south-facing wall or fence is ideal
• Good drainage — waterlogged roots cause all sorts of problems

Step-by-Step Planting Out Guide

1. Check the forecast — make sure no frost is expected for at least two weeks.
2. Water your plants well the night before planting.
3. Dig a hole deeper than the root ball — tomatoes can form roots along their buried stem, which strengthens the plant.
4. Plant deeply — bury the stem up to the lowest set of leaves if the plant is leggy.
5. Firm in gently and water thoroughly.
6. Insert a stake or cane immediately for cordon varieties — tie loosely with soft jute twine.
7. Space plants 45–60cm apart for cordons, 60–90cm for bush varieties.
8. Water in with a diluted liquid feed to help roots establish.

Feeding: The Key to a Good Crop

Once the first flowers appear, start feeding weekly with a high-potassium tomato feed. We stock Neudorff Organic Tomato Feed, a concentrated organic option that won't overwhelm the plant. Before flowering, a balanced feed higher in nitrogen helps build strong leafy growth — then switch to high-potassium once flowers appear.

Watering

Water regularly and consistently — irregular watering is the main cause of blossom end rot and split fruit. Aim to keep the compost moist but not waterlogged. In hot spells, container-grown tomatoes may need watering twice a day. Always water at the base of the plant, not over the leaves — wet foliage encourages blight.

Pinching Out Side Shoots (Cordon Varieties)

Pinch out the side shoots that appear in the joints between the stem and leaves when they're small. At the end of August, pinch out the growing tip to focus the plant's energy on ripening existing fruit. Tie in stems regularly using soft jute twine — it's gentle on stems and biodegradable. Bush varieties don't need pinching out.

Pests and Diseases: What to Watch For

Blight (Phytophthora infestans)

The most serious threat to UK tomatoes. Look for brown patches on leaves and stems, and dark sunken patches on fruit. Water at the base, ensure good airflow, and remove and bin any affected material immediately. A copper-based fungicide can help protect plants if applied before infection takes hold.

Aphids (Greenfly)

Clusters of small green insects on new growth. Treat early or squash by hand. In a greenhouse, introduce biological controls like parasitic wasps.

Whitefly

Common in greenhouses. Yellow sticky traps help monitor numbers. Biological controls (Encarsia formosa) are very effective.

Red Spider Mite

Causes mottled, pale leaves and fine webbing. Thrives in hot, dry conditions — maintain humidity and use biological controls.

Blossom End Rot

A dark, sunken patch at the base of the fruit caused by irregular watering. Consistent watering is the fix.

Split Fruit

Caused by irregular watering after a dry spell. Keep moisture levels consistent and harvest promptly when ripe.

When to Harvest

Most UK tomatoes are ready from July through to October. Pick when fully coloured and slightly soft to the touch. Pick regularly to encourage more fruit. At the end of the season, green tomatoes can be ripened on a sunny windowsill or used to make green tomato chutney.

What to Do With a Glut

• Freeze them — blanch, skin, and freeze whole or as a passata.
• Make chutney — green or red, tomato chutney keeps for months.
• Slow-roast — halve, drizzle with olive oil and roast low and slow. Keeps in the fridge for a week.
• Sun-dried tomatoes — slice thinly and dry in a low oven or dehydrator. Store in olive oil.
• Give them away — neighbours, colleagues, food banks. Homegrown tomatoes are always welcome.

Frequently Asked Questions

Why are my tomato leaves curling?

Leaf curl is usually caused by heat stress, irregular watering, or over-feeding. Check your watering routine first — if the compost is dry, water thoroughly and consistently. If the plant is in direct sun in a greenhouse, improve ventilation. Viral infections can also cause leaf curl, in which case remove and dispose of the plant.

Can I grow tomatoes in shade?

Tomatoes need at least 6–8 hours of direct sun to crop well. In shade, plants will grow but produce little fruit and be more susceptible to disease. If your garden is shady, choose a cherry variety and place it in the sunniest spot available — even a south-facing windowsill can work for a small plant.

How many tomatoes will I get per plant?

It varies hugely by variety and conditions. A well-grown cordon tomato in a greenhouse can produce 4–6kg of fruit. Cherry varieties are prolific — Gardener's Delight can produce hundreds of small fruits per plant. Outdoor plants in a poor summer will produce less, but even a modest crop is deeply satisfying.

Do I need to pollinate my tomatoes?

Outdoors, wind and insects handle pollination naturally. In a greenhouse, give plants a gentle shake every few days when in flower, or use a soft paintbrush to transfer pollen between flowers. This significantly improves fruit set.

Why are my tomatoes not turning red?

Tomatoes need warmth to ripen — they actually stop producing lycopene (the red pigment) above 30°C and below 10°C. At the end of the season, bring green tomatoes indoors to ripen on a windowsill. Placing them next to a ripe banana speeds up the process.

Can I save tomato seeds for next year?

Yes, from open-pollinated (non-F1) varieties. Scoop seeds into water, ferment for 2–3 days, rinse, dry thoroughly, and store in a cool dry place. F1 hybrid seeds won't come true to type, so it's not worth saving those.

Everything You Need from Grasmere Garden Centre

• Tomato seeds: Sungold F1, Gardener's Delight, Tumbling Tom, Moneymaker and more
• Growmoor Tomato Planter Compost 56L
• GroWorm Black Gold Peat Free Organic Tomato Planter 56L
• Growmoor 4 Plant Growbag 38L
• Neudorff Organic Tomato Feed
• Ambassador Green Jute Twine for tying in