Ultimate Guide to Growing Tomatoes in the UK

Tomatoes are one of the most rewarding crops to grow in the UK. Whether you have a large allotment, a greenhouse, raised beds, or just a sunny patio with containers, tomatoes can provide a long harvest season and flavours far superior to supermarket fruit.

This comprehensive guide covers everything you need to know about growing tomatoes in the UK, including choosing varieties, sowing seeds, feeding, watering, preventing disease, and harvesting bumper crops.

Why Grow Your Own Tomatoes?

Home-grown tomatoes offer several advantages over shop-bought fruit:

• Superior flavour and freshness
• A huge range of varieties unavailable in supermarkets
• High yields from relatively small spaces
• Suitable for gardens, allotments, greenhouses and containers
• Excellent for beginners and experienced gardeners alike

Tomatoes are also versatile in the kitchen. They can be eaten fresh in salads, cooked into sauces, dried, frozen, or preserved as chutneys and relishes.

Choosing Tomato Varieties

One of the biggest advantages of growing your own tomatoes is the enormous range of varieties available. Garden centres and supermarkets usually offer only a handful of types, but home gardeners can choose from hundreds of cultivars with different flavours, colours, sizes and growth habits.

Before selecting a variety, consider:

• Whether you are growing indoors or outdoors
• Available growing space
• Whether you want salad, cooking or preserving tomatoes
• Your local climate
• Disease resistance

Many gardeners find it worthwhile growing several varieties rather than relying on a single type. A combination of cherry, salad and beefsteak tomatoes can provide fruit throughout the season and offer a wider range of flavours and culinary uses.

Bush Tomatoes (Determinate)

Bush tomatoes grow to a predetermined size before stopping vertical growth. They form compact plants that are particularly suitable for containers, hanging baskets, grow bags and smaller gardens.

Most bush varieties require little pruning and only minimal support, making them an excellent choice for beginners.

Popular UK varieties include:

• Roma
• Red Alert
• Tumbling Tom
• Vilma

Because bush tomatoes produce much of their crop over a relatively short period, they are often favoured by gardeners who wish to make sauces, chutneys or preserve tomatoes in bulk.

Cordon Tomatoes (Indeterminate)

Cordon tomatoes continue growing and producing flowers throughout the season until stopped by frost or the gardener removing the growing tip.

These varieties require support from canes, strings or specialist support systems. Side shoots are usually removed regularly to concentrate the plant’s energy into fruit production.

Popular cordon varieties include:

• Gardener’s Delight
• Sungold
• Alicante
• Moneymaker
• Shirley

Although cordon tomatoes require more maintenance, they often provide a longer harvest season and can produce exceptionally heavy crops when grown well.

When to Sow Tomato Seeds

Timing is important for successful tomato growing in the UK.

Southern UK

• Sow indoors from January to March

Northern UK

• Sow indoors from February to April

Tomatoes need warmth to germinate, so seeds are usually started indoors on a windowsill, in a heated propagator, or in a greenhouse with additional heat.

How to Sow Tomato Seeds

• Fill small pots or seed trays
  • Use a quality seed compost with good drainage.
• Sow the seeds
  • Place seeds about 0.5 cm deep and cover lightly with compost.
• Water gently
  • Keep the compost moist but not waterlogged.
• Provide warmth
  • Maintain a temperature of around 18–24°C for best germination.
• Give plenty of light
  • Once seedlings emerge, move them to a bright position to prevent leggy growth.

Germination usually takes 7–14 days.

Potting On Seedlings

When seedlings develop their first true leaves, pot them on into larger containers.

• Handle seedlings carefully by the leaves
  • Avoid damaging the delicate stems.
• Plant slightly deeper
  • Tomatoes can root along buried stems, producing stronger plants.
• Use a larger pot and fresh compost
  • Provide enough space for roots to develop and maintain steady growth.

Repeat potting on if plants outgrow their containers before planting time.

Hardening Off

Before planting outdoors, tomato plants must be hardened off to acclimatise them to cooler temperatures and outdoor conditions.

Start about 7–10 days before planting:

• Place plants outside in a sheltered spot during the day.
• Bring them indoors at night initially.
• Gradually increase outdoor exposure each day.
• Protect from strong wind and cold temperatures.

Plant out only after the risk of frost has passed.

Growing Tomatoes in a Greenhouse

Greenhouses provide the warmth and protection tomatoes love. They allow:

• Earlier planting
• Longer harvests
• Better fruit ripening
• Reduced risk of outdoor blight

For greenhouse growing:

• Space plants about 45–60 cm apart.
• Use canes, strings or support systems.
• Ventilate regularly to reduce humidity and disease risk.
• Water consistently and feed regularly once flowering begins.

A greenhouse does not need to be heated during summer, but early sowings benefit from additional warmth in late winter.

Growing Tomatoes Outdoors

Outdoor tomatoes can grow very successfully in the UK during a good summer.

Choose:

• A warm, sunny location
• Sheltered conditions protected from strong winds
• Fertile, well-drained soil

Outdoor plants benefit from:

• Mulching to retain moisture
• Regular feeding
• Good spacing for airflow
• Support for taller varieties

In cooler regions, cherry tomatoes and early-maturing varieties are often the most reliable outdoors.

Growing Tomatoes in Containers

Tomatoes are excellent container plants and can thrive on patios, balconies and small gardens.

For best results:

• Use large containers of at least 30–40 cm diameter.
• Choose quality compost with good moisture retention.
• Ensure containers have drainage holes.
• Water frequently, especially during hot weather.
• Feed regularly once flowers appear.

Bush varieties are ideal for pots, but cordon tomatoes can also perform well in large containers with proper support.

If you are interested in container growing, you may also find these guides useful:

• Container Gardening: https://www.theallotmentgarden.co.uk/container-gardening/
• Container Vegetable Gardening: https://www.theallotmentgarden.co.uk/container-vegetable-gardening/

Feeding Tomatoes

Tomatoes are hungry plants and benefit from regular feeding throughout the growing season.

Early Growth

Use a balanced feed or one slightly higher in nitrogen to encourage leafy growth.

Flowering and Fruiting

Switch to a high-potash tomato feed once flowers appear. Potassium promotes flowering, fruit development and flavour.

Feed every 1–2 weeks during the main growing season.

Watering Tomatoes Correctly

Incorrect watering is responsible for many tomato problems, including split fruit, blossom end rot and inconsistent growth.

Tomatoes prefer consistently moist soil rather than cycles of drought and flooding.

Key Watering Tips

• Water deeply rather than little and often.
• Avoid wetting the leaves where possible.
• Water in the morning or evening.
• Keep moisture levels even.
• Mulch around plants to conserve water.

Container-grown tomatoes dry out quickly and may need watering daily in warm weather.

For gardeners using automated watering, see:

• Garden Irrigation Systems: https://www.theallotmentgarden.co.uk/garden-irrigation-systems/

Supporting Tomato Plants

Cordon tomatoes need support as they grow.

Common methods include:

• Canes: bamboo canes tied to the main stem.
• String systems: ideal for greenhouses.
• Tomato cages: useful for bush varieties and containers.

Tie stems loosely with soft twine or plant ties to avoid damage.

Removing Side Shoots

Cordon tomatoes produce side shoots in the angle between the main stem and leaves.

These should usually be removed regularly by pinching them out with your fingers. Removing side shoots helps the plant focus energy on fruit production and improves airflow.

Bush tomatoes generally do not need side shoots removed.

Pollination

Outdoor tomatoes are usually pollinated by wind and insects.

In greenhouses, pollination can sometimes be improved by:

• Gently shaking flower trusses.
• Tapping support canes.
• Encouraging airflow with ventilation.

Poor pollination can lead to flowers dropping without setting fruit.

Common Tomato Problems

Yellow Leaves

Often caused by:

• Overwatering
• Underfeeding
• Natural ageing of lower leaves
• Cold conditions

Remove affected lower leaves and correct watering or feeding if necessary.

Split Fruit

Usually caused by irregular watering after a dry period. Maintain even moisture levels to reduce splitting.

Blossom End Rot

Appears as a dark, sunken patch on the base of fruit. It is usually linked to inconsistent watering rather than a simple calcium deficiency.

Leaf Curl

Leaves may curl due to heat stress, irregular watering, or occasionally pests and disease. Mild curling is often not serious.

Tomato Diseases

Tomato Blight

Blight is one of the most serious tomato diseases in the UK, especially during warm, damp summers.

Symptoms include:

• Brown patches on leaves
• Dark streaks on stems
• Brown or black fruit rot

Remove affected foliage promptly and avoid watering leaves.

Fusarium Wilt

A soil-borne disease that causes yellowing, wilting and decline. Crop rotation and resistant varieties help reduce risk.

Leaf Mould

Common in humid greenhouses with poor ventilation. Improve airflow and avoid overcrowding plants.

Tomato Pests

Common tomato pests include:

• Whitefly: tiny white insects often found in greenhouses.
• Aphids: clusters of sap-sucking insects on young growth.
• Red spider mite: causes fine webbing and speckled leaves in hot, dry conditions.
• Slugs: can damage young plants and fruit.

Encouraging beneficial insects and using organic control methods can help keep pest numbers under control.

Useful related guides:

• Companion Planting for Pest Control: https://www.theallotmentgarden.co.uk/companion-planting-for-pest-control/
• Natural Pest, Weed and Herbicides: https://www.theallotmentgarden.co.uk/natural-pest-weed-herbicides/

Companion Planting for Tomatoes

Companion planting can improve tomato growth, attract pollinators and help deter pests.

Excellent companions include:

• Basil
• Marigolds
• Nasturtiums
• Garlic
• Chives
• Lettuce

Avoid planting tomatoes close to potatoes, as they can share diseases such as blight.

For a detailed guide, see:

• Companion Planting Tomatoes: https://www.theallotmentgarden.co.uk/companion-planting-tomatoes/

Harvesting Tomatoes

Tomatoes are ready to harvest when they are fully coloured and slightly soft to the touch.

• Pick fruit regularly to encourage continued production.
• Harvest in dry weather where possible.
• Use scissors or secateurs for large trusses to avoid damaging stems.

Towards the end of the season, remove the growing tip from cordon tomatoes so the plant focuses on ripening existing fruit.

Saving Tomato Seeds

Tomatoes are one of the easiest vegetables for seed saving, especially open-pollinated varieties.

How to Save Seeds

• Choose a ripe, healthy tomato
  • Select a fruit from a vigorous, disease-free plant.
• Scoop the seeds into a jar
  • Include the surrounding gel from the centre of the tomato.
• Allow the mixture to ferment for 2–3 days
  • Leave it at room temperature until mould forms on the surface.
• Rinse and dry the seeds
  • Wash away the gel, then spread seeds on paper to dry thoroughly.
• Store in a cool, dry place
  • Keep dried seeds in a labelled envelope or container.

Saved seeds can remain viable for several years when stored correctly.

Frequently Asked Questions

How many tomatoes will one plant produce?

A healthy cordon tomato can produce dozens of fruits over the season, while bush varieties usually produce a more concentrated crop.

Can tomatoes grow in shade?

Tomatoes need plenty of sunlight for good growth and fruiting. They perform best in at least 6–8 hours of direct sun daily.

Should I remove tomato leaves?

Lower leaves can be removed once fruit trusses begin ripening, especially if they touch the soil or reduce airflow. Avoid removing too much foliage at once.

Can tomatoes survive winter?

Tomatoes are tender plants and will not survive frost outdoors in the UK. Some gardeners overwinter cuttings indoors, but most plants are treated as annuals.

Why are my tomato flowers dropping?

Flower drop can be caused by:

• Temperatures that are too high or too low
• Poor pollination
• Irregular watering
• Excessive nitrogen feeding

Final Thoughts

Growing tomatoes in the UK is both enjoyable and productive. With the right variety, a sunny position, consistent watering and regular feeding, even beginner gardeners can achieve impressive harvests.

Whether you are growing a few plants on a balcony or rows of tomatoes on an allotment, the reward of picking ripe, flavour-packed fruit straight from the plant is hard to beat.