When to sow tomato seeds
Sow your tomato seeds between February and April. If you’re using an outdoor heated greenhouse, sow your tomato seeds in February. If you’re using a sunny windowsill then sow your tomato seeds in late March to April when light levels are higher.
Large tomato varieties such as the beefsteak tomatoes ‘Marmande’ and ‘Noire de Crimee’ need a longer growing season to give their gigantic fruits time to ripen, so sow these seeds in February. Sow smaller, faster ripening cherry varieties like ‘Gardeners Delight’ in April.
How to grow tomatoes from seed
Grow tomatoes from seed using good quality organic tomato seeds. Use fine seed compost to fill your seed tray, small pots or repurposed yoghurt pots. Dampen the soil and gently press the seeds into the surface before lightly sprinkling more compost over to cover them. Spray the soil surface with water using a mister or water your pots from the bottom to minimise disturbance to the seeds and place in a warm sunny space to germinate.
Pot on your tomato seedlings when they have at least two true leaves. Use multi-purpose compost, planting one plantlet per pot. Pinch out any side shoots as they appear. Harden off your plants for two weeks before planting them outdoors in May. Skip this if you’re planting straight into greenhouse beds.
How to sow tomato seeds
Gently scatter your tomato seeds over a seed tray onto damp seed compost. Lightly cover the seeds with a sprinkling of vermiculite or compost and place the trays in a warm place at around 18°C with a clear plastic covering. Make sure you keep the trays damp but not waterlogged — a misting spray bottle is helpful here.
As soon as you see germination happening, move the tray into a bright sunny position. Turn your seedlings every few days to keep them from leaning towards the light. If you notice your seedlings getting leggy and pale, increase light levels during the day using a grow light or move them to a sunnier position in the house.
How long do tomato seeds take to germinate?
Tomato seeds typically take around two weeks to germinate. Warmer temperatures between 18°C and 15°C encourage quicker germination, whereas temperatures between 10°C and 18°C may slow germination down to around three weeks. Always buy good quality tomato seeds from a trusted supplier to see the best results from germination.