Sow indoors
February – April
Sow direct
—
Plant out
May – June
Harvest
July – October
Days to maturity
60–90 days
Position
Full sun
Frost sensitive
Yes
Min soil temp
15°C
Sowing and planting calendar
| Method | From | To | Notes |
|---|---|---|---|
| Indoors (heated propagator) | February | April | Minimum 18°C. South-facing windowsill or heated propagator. |
| Indoors (unheated) | March | April | Wait until March without heat — germination unreliable below 15°C. |
| Plant out (south England) | Late May | June | After last frost. Nights consistently above 10°C. |
| Plant out (north / Scotland) | Early June | Late June | Later last frost dates — don't rush. |
Regional variation: In Scotland and northern England, last frost dates can fall as late as early June. In Cornwall and south Wales, you may plant out from mid-May. Always check your local forecast.
Growing tips
Start indoors — they need warmth to germinate
Tomato seeds need a minimum of 15°C to germinate, ideally 20–25°C. Sow into small pots, cover with cling film or a propagator lid, and keep somewhere warm.
Harden off before planting out
Harden off over 10–14 days by gradually increasing outdoor exposure. Only plant out permanently when overnight temperatures stay above 10°C.
Pinch out side shoots on cordon varieties
Cordon tomatoes produce side shoots in the leaf axils — pinch these out weekly. Bush varieties don't need this. Check your seed packet.
Feed once fruits start to set
Switch to a high-potassium tomato fertiliser weekly once the first fruits have set. Over-feeding with nitrogen earlier produces leafy plants with poor fruit set.
Water consistently — avoid boom and bust
Irregular watering causes blossom end rot and fruit splitting. Keep compost consistently moist — never waterlogged, never allowed to dry out completely.
Common problems
Late blight
ACT NOWDark water-soaked patches on leaves, spreading rapidly. Can kill a plant within days in warm, wet summers.
Fix: Remove and destroy affected plants immediately. Choose blight-resistant varieties like Crimson Crush or Ferline next year.
Early blight (Alternaria)
Brown spots with yellow halos on lower leaves, spreading upwards in warm, wet conditions.
Fix: Remove affected leaves. Improve airflow. Copper fungicide if severe.
Yellow leaves
Can indicate nitrogen deficiency, magnesium deficiency, overwatering, or natural senescence on mature plants.
Fix: Lower leaf yellowing on a fruiting plant is often normal. For nutrients: feed with balanced fertiliser or Epsom salts for magnesium.
Whitefly and aphids
Whitefly cluster under leaves; aphids on stems and new growth. Both weaken plants.
Fix: Yellow sticky traps. Biological controls work well in greenhouses. Outdoors, encourage natural predators.
Blossom end rot
Black, sunken patch at the base of the fruit — caused by calcium deficiency from irregular watering.
Fix: Water more consistently. The root cause is almost always irregular moisture, not lack of calcium in the soil.
Frequently asked questions
When should I sow tomatoes in the UK?
Sow indoors from February (with heat) to April. February sowings need a heated propagator above 18°C. March is the most reliable month for most growers.
When can I plant tomatoes outside?
After your last frost, when nights are consistently above 10°C. In south England typically late May; north and Scotland, early to mid June.
Do I need to pinch out side shoots?
Only for cordon (indeterminate) varieties. Bush varieties are left to grow naturally — check your seed packet.
Why aren't my tomatoes ripening?
Usually low light and dropping temperatures in late summer. Remove shading leaves, bring containers indoors in September.
Related guides
Keep track of your tomatoes in Vercro
Add your tomatoes to a bed and each morning Today shows the jobs that matter for them, from how far along they are and your local forecast, including a blight look-out when conditions suit it.
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