Tomatoes are a relatively easy plant to grow, and can produce up to 3 kg (6 1/2 lb) of fruit per plant. As they are sub-tropical, they need to be grown in a warm, sunny and sheltered position, achieving their optimum growth at 21-24°C (70-75°F). However, they do not grow well at temperatures above 27°C (81°F) or below 16°C (61°F).

Tomatoes cannot tolerate any degree of frost, and must be sown when the soil temperature is (and will remain) above 10°C (50°F) - any lower and the seeds will not germinate. For the majority of UK gardens, this requirement means that tomato seeds must be sown under cover, and transplanted to the open soil well after the risk of late frosts have passed.

Sowing

Sow tomato seeds 7 weeks before you intend to plant them out in the open garden; this should be 3 weeks after the last frost date. For example, if the last frosts in your area are at the very end of April, you will be able to transplant the young seedlings towards the end of May, having sown them under cover at the beginning of April.

Sow seeds in a good potting compost, ensuring that the soil is moist, but not waterlogged. Keep them in a heated propagator or other warm (up to 27°C or 80°F) draught free place until the seedlings emerge 7-10 days later.

At this point, move them to a light position, such as a windowsill or greenhouse. Thin and prick out as necessary, then harden them off over 2 weeks before planting out.

Planting Out

Transplant young tomato seedlings grown under cover or bought at the garden centre into their final positions when they are about 15 cm (6 in) high. This should be done at least 3 weeks after the last frosts - usually about the end of May. Just before transplanting, drive a stake into the ground 5 cm (2 in) from the planting position; this should be at least 30 cm (12 in) deep in the ground and 120 cm (48 in) above ground level.

Although plants may transplanted directly into soil enriched with a generous helping of well-rotted manure or garden compost, you could also use large pots filled with multipurpose compost or growing bags. A 10 or 15 litre pot will take 1 seedling, whilst a standard grow bag will take 2 or 3 plants.

Plant the seedlings 45 cm (18 in) apart and loosely tie the plant's stem to the support stake using soft garden twine. As the main stem grows, pinch out any side-shoots that form, taking care not to damage the tiny clusters of yellow flowers.

Maintenance

The plants will need frequent watering to keep the soil moist; this may mean twice a day in growing bags or pots. The plants should also be fed with a liquid tomato fertiliser once the first fruits start to form. This should be carried out once a week for plants in grow-bags or containers, or every two or three weeks for those in the open soil.

In early September, pinch out the growing tip of the main shoot to prevent further trusses of fruit developing and allow the trusses already formed to ripen. Keep pinching out any side-shoots. Feed with a general fertilizer (high in nitrogen) to encourage the development of healthy foliage.

Harvesting

Pick the fruits as soon as they are ripe, removing any dead or yellowing leaves or mouldy fruit from the bottom of the plant. This will encourage the production of more fruit. As soon as frost is predicted, harvest the remainder of the fruit, and allow them to ripen on a warm windowsill.