When to Plant Tomatoes

In the UK, tomato seeds are typically sown indoors between late February and April. This early start gives plants enough time to develop before being moved outside after the last frost. Tomato plants are highly sensitive to cold and should only be planted out once night temperatures consistently stay above 10°C—usually from mid-May to early June, depending on your region. For greenhouse growing, tomatoes can be planted a few weeks earlier as long as the environment remains warm and frost-free.

How to grow tomatoes

Tomatoes thrive in full sun, fertile soil and consistent warmth. They can be grown in greenhouses, polytunnels, pots, grow bags or directly in garden beds. Start by sowing seeds in trays or small pots with seed compost, keeping them at around 18–21°C. Once the seedlings develop two sets of true leaves, they should be moved into individual pots to continue growing. Gradually acclimatise them to outdoor conditions before planting out. Tomato plants are hungry feeders and need regular watering, feeding and support.

How to grow tomatoes at home

Tomatoes are well suited to home growing, whether in gardens, on patios or balconies. Compact bush types do well in containers, while cordon varieties grow vertically and need support. Choose a warm, sheltered spot with plenty of sun, and make sure pots or grow bags have good drainage. Add organic compost and a controlled-release feed when planting. With the right setup and care, even a small space can yield an impressive crop of homegrown tomatoes.

Planting tomatoes

Tomatoes should be planted out once the risk of frost has passed and the plants are about 15–20cm tall. Prepare the planting area by enriching the soil with compost or well-rotted manure. Plant seedlings deeply, burying the stem up to the first set of leaves. This encourages stronger root growth and a more stable plant. Space plants around 40–50cm apart and water them in well. For container growing, use large pots with at least 30cm depth and width.

Caring for tomatoes

Tomatoes need regular attention to stay healthy and productive. Water consistently, aiming to keep the soil evenly moist but not waterlogged. Fluctuating moisture can cause problems like blossom end rot. Feed every 10–14 days with a high-potash fertiliser once flowering begins. Cordon (indeterminate) varieties need side shoots pinched out and should be tied to stakes or supports as they grow. Bush (determinate) types are lower maintenance but benefit from occasional pruning and deadheading.

Growing tomatoes

Success with tomatoes depends on light, warmth and feeding. In cooler areas, growing under glass or in a sunny, protected microclimate helps extend the season. Tomatoes are self-pollinating, but gently shaking the flowers or growing near pollinator plants can boost fruit set. Mulching around the base of plants helps retain moisture and reduce weed competition. As the season progresses, remove lower leaves to improve airflow and reduce the risk of disease.

Where to buy tomatoes

Tomato seeds and young plants are widely available online, in garden centres and from local nurseries. Seed companies offer a huge selection, from heritage favourites to blight-resistant hybrids. For beginners, buying young plug plants is an easy way to get started without having to raise from seed. Those looking for rare or flavour-packed varieties should explore specialist seed suppliers or community seed swaps.

Tomato varieties to grow

There’s a tomato for every garden and growing style. Cordon varieties such as ‘Gardener’s Delight’ and ‘Shirley’ are excellent for greenhouses or open ground, producing large trusses of fruit over a long season. Bush types like ‘Tumbling Tom’ and ‘Balconi Red’ are ideal for containers and hanging baskets. For flavour, try heritage varieties like ‘Brandywine’ or ‘Black Krim’. If blight is a concern, modern resistant strains like ‘Crimson Crush’ offer extra reassurance.

Best tomatoes for flavour

Flavour is where tomatoes really shine. Cherry tomatoes like ‘Sungold’ are renowned for their sweetness and are perfect for snacking. ‘Ailsa Craig’ has a traditional balance of sweet and sharp, ideal for sandwiches. Larger varieties like ‘Marmande’ or ‘Costoluto Fiorentino’ offer rich, meaty flesh perfect for cooking. Soil health, sunlight and consistent watering all play a role in maximising taste.

Best tomatoes for containers

Compact or bush varieties are best for growing in pots. ‘Tumbling Tom’ is a popular trailing type perfect for baskets, while ‘Balconi Yellow’ adds colour and sweetness in a small space. Choose a large container with drainage holes and use a quality peat-free compost. Keep pots regularly watered and feed with tomato fertiliser once fruit sets to keep the plants productive.

How to sow tomato seeds

Sow seeds indoors from late February to early April. Fill trays or small pots with seed compost and place seeds about half a centimetre deep. Cover lightly with compost and water gently. Keep them in a warm place—18 to 21°C is ideal. Once germinated, place seedlings in a bright spot, ideally under grow lights or on a sunny windowsill. Pot them on when they develop their second set of true leaves.

Planting out tomato seedlings

Once all risk of frost has passed, and plants are well established, it’s time to plant them out. Harden them off by gradually introducing them to outdoor conditions over 7–10 days. Plant deeply in rich, warm soil and stake tall varieties straight away. Space plants generously to allow airflow, which helps prevent blight and other fungal issues. Water in well and keep the soil consistently moist in the early days of establishment.

Timing depends on how you’re growing them

The key to knowing when to plant tomatoes isn’t just about the calendar—it’s about where and how you plan to grow them. If you're planting in a greenhouse, you can transplant seedlings from late April onwards, assuming nights are frost-free and the structure is properly ventilated. For outdoor planting, wait until mid-May to early June, or later if you're in a cooler northern region. Even one unexpected frost can wipe out young plants overnight, so it’s better to wait a week longer than rush them out.

Soil temperature is a better guide than air temperature

Tomatoes hate cold feet. Even if the weather feels warm during the day, cold soil can stunt their growth or cause transplant shock. Aim for a consistent soil temperature of 12–15°C or higher before planting out. You can warm the soil up faster by covering it with black plastic or a cloche a week or two ahead of time.

Don't forget hardening off

Tomato seedlings grown indoors or in a greenhouse need to be hardened off before being planted outdoors. This is a vital but often skipped step. Over the course of 7–10 days, gradually introduce the plants to outdoor conditions—start by placing them outside during the day and bringing them in at night. Without this step, the sudden shock of wind, cooler temps and intense sunlight can set them back.

Earlier isn’t always better

It’s tempting to sow tomatoes in early February, but unless you have grow lights and heated propagators, you’ll end up with weak, leggy seedlings desperate for light. For most home growers, late March to early April is the sweet spot for sowing—especially if you're relying on windowsill light. Later sowings catch up quickly as days get longer and warmer.

Late sowings can still produce

If you’ve missed the usual sowing window, don’t give up. Tomato seeds sown as late as early May can still produce a crop—especially fast-maturing cherry or bush varieties. You might not get quite as big a harvest, but it’s still worth doing, especially if you're growing in a warm, sunny spot or under cover.

Watch out for overgrown seedlings

If you sow early but can’t plant out due to lingering cold, seedlings can become pot-bound or leggy. To manage this, pot them on into larger containers as needed and keep them in the brightest, coolest area you have until they can go outside. Pinch off lower leaves if stems get too long—tomatoes can be planted deeper than most plants, encouraging them to grow more roots along the buried stem.

Keep an eye on the weather

A warm spell in April doesn’t mean it's safe to plant out yet. The UK spring is unpredictable. Always keep an eye on local frost forecasts, not just general advice. If needed, you can cover young plants with fleece, cloches or upturned plastic bottles overnight for extra protection.