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1 October 2020

How to grow tomatoes

Try growing your own tomatoes for unbeatable flavour this summer
Tomato plant
Ceri Thomas

Sow tomato seed

  • Always choose a Best Buy variety for the tastiest tomatoes.
  • Sow the seed in March for plants to be grown in the greenhouse or April for plants to be grown outdoors.
  • However if you want the earliest crop of tomatoes, you can sow as early as the first week of February on a windowsill as long you can keep them indoors until night-time temperatures in your unheated greenhouse are over 10C. If you can't, sow in Mid-February, then you can move them into an unheated greenhouse as soon as they come up.
  • Start off the seed at a temperature of 20C, in a heated propagator or a well-lit windowsill. Use a Best Buy compost for sowing seeds.
  • Sow several seeds in a 7cm pot. Most seeds will germinate, so only grow as many as you need.
  • When the seedlings are large enough, tease them apart and pot them into individual 7cm pots.
  • Keep them somewhere reasonably warm (about 15C) and well-lit to avoid the seedlings growing tall and spindly.
  • If the roots start to fill the pots before you can plant them out, move them into bigger ones.

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Caring for your tomato plants

  • Greenhouse plants can be planted in growing bags or the greenhouse border in early May. Use a Best Buy growing bag.
  • Outdoor plants can go out in early June, either in the ground or in 10-litre pots or a hanging basket in a sunny, sheltered spot.
  • Water tomato plants regularly. Plants in containers should be given a thorough soak every morning and every evening, especially in dry spells.
  • Apply a liquid tomato food to feed the developing fruit.

Training tomato plants

  • The easiest option outdoors is to go for a 'bush' varieties as they don't need training. A dwarf bush variety is the best option for a container or hanging basket.
  • Most tomatoes are grown as cordons, which means they are limited to one stem. To train them, you need to remove the shoots that grow between the main stem and the leaves. The plant needs to be regularly tied to a cane or some other support as it will grow very tall.

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Tomato problems


can devastate tomatoes and is a more common problem on outdoor plants. Affected plants should be destroyed.

Flowers dropping without setting fruit or with undersized fruits can be due to dry air or dryness at the roots.

Greenback - yellow patches on the shoulder of the fruit - is caused by heat injury from direct sunlight, very high temperatures or insufficient potash. Older varieties are more susceptible.

Uneven ripening can also be due to insufficient potash, lack of moisture or excessive heat.

Blossom end rot - a sunken dark patch on the bottom of the fruit - is caused by inadequate or irregular watering early in the fruit's development. Later trusses should not be affected if you water more regularly.