Fruiting vegetable
How to grow tomatoes
Solanum lycopersicum
Sow tomatoes indoors from late February to early April at 18 to 21 °C, pot on, and plant out when the first truss shows flowers: May in a greenhouse, after the last frost outdoors. Give them full sun and shelter, tie in cordons and pinch out their side shoots, and water evenly so the fruit does not split or develop blossom end rot. Start a high-potash feed once the first truss has set.
- Hardiness
- Tender, frost kills it
- Position
- Full sun, sheltered
- Soil
- Rich, moisture-retentive, free-draining
- Ideal pH
- 6.0 to 6.8
- Water
- High, steady and even; never let pots dry out
- Feeding
- Heavy feeder
Sowing and planting tomatoes
WhenSow Feb to Apr indoors; plant out late May to Jun (earlier under glass); harvest Jul to Oct
Starting off
Sow indoors 0.5 cm deep in modules or a seed tray at 18 to 21 °C; seedlings show in 6 to 10 days. Sow late Feb to Mar for a heated greenhouse, late Mar to early Apr for outdoors. Prick out at the two-leaf stage into 9 cm pots and grow on at 15 to 18 °C, planting out when the first truss shows flowers.
Spacing and planting
Cordons 45 to 60 cm apart in rows 75 to 90 cm apart, or 45 cm apart in a greenhouse border; bush types 60 to 90 cm each way. Plant deep, burying the stem to the first true leaves. Cordons crop well in a 30 cm pot or a three-plant growbag; bush and tumbling types suit 25 cm pots and baskets.
Varieties worth growing
- Gardener's Delight
- Red cherry, cordon, crops outdoors or under glass and rarely fails. The one to learn on.
- Sungold F1
- Orange cherry and the sweetest tomato most people will taste. Cordon, greenhouse or a warm wall; skins split if watering lapses.
- Shirley F1
- Medium red, early and heavy under glass, with built-in resistance to leaf mould and the common viruses.
- Crimson Crush F1
- Large round tomato with strong blight resistance, so it is the outdoor choice in a wet summer.
- Tumbling Tom Red
- Trailing bush for a basket or 25 cm pot; no side-shooting, no staking.
Tomatoes month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Order seed. Nothing to sow yet unless you have a heated greenhouse.
- February
Sow late in the month for a heated greenhouse, 18 to 21 °C.
- March
Sow for a cold greenhouse. Late March for outdoor plants.
- April
Prick out into 9 cm pots at the two-leaf stage. Pot on as roots fill the pot.
- May
Plant into the greenhouse early in the month. Harden off outdoor plants over 7 to 10 days.
- June
Plant outdoors after the last frost. Stake cordons, start side-shooting weekly, feed from the first truss.
- July
Top-dress pots every 2 to 4 weeks and water it in. Water every day in pots. Remove leaves below the lowest truss.
- August
Stop cordons two leaves above the fourth truss outdoors (sixth or seventh under glass). Watch for blight.
- September
Harvest. Pick everything green before the first frost warning.
- October
Ripen green fruit indoors. Clear plants; compost only if blight-free.
- November
Wash down the greenhouse glass and staging.
- December
Rest. Plan next year's varieties.
Feeding tomatoes
A heavy feeder. Tomato Fertiliser at planting, the same dry feed as a top-dress from the first truss, nothing once the last fruit is colouring.
Balanced feed while growing on, then switch to a high-potassium feed once the first truss sets to drive flowering, fruiting and flavour. Excess nitrogen gives leaf at the expense of fruit.
Feeding plan
At planting, pots
5 g per litre of fresh compost: about 60 g in a 12 litre pot, 175 g in a 35 litre three-plant growbag.
First truss setting, beds
50 g/m² scattered round the plants and watered in. With the 100 g/m² at planting, that is the whole of the label's bed feeding.
First truss to last fruit colouring, pots and growbags, every 2 to 4 weeks
1 to 3 g per litre of pot volume, scattered on the compost and watered in: 12 to 36 g for a 12 litre pot, 35 to 105 g for a 35 litre growbag. Use the low end every 2 weeks or the high end every 4, not both.
Every 2 to 3 weeks from first truss
1 to 2 g per litre of water as a drench; the magnesium stops the high-potash feed yellowing the older leaves.
Any time the plant looks stressed
1 g per litre as a foliar spray, weekly for 2 to 3 weeks.
Signs to watch
Dark sunken patch on the fruit base
Blossom-end rot from erratic watering, not a calcium shortage
Water evenly and mulch
Older leaves yellow between green veins
Magnesium locked out by heavy potash feeding
Epsom salts as a foliar spray
Huge dark leaves and few flowers
Excess nitrogen
Stop balanced feeding and switch to high-potash
Pests, diseases and problems
Brown patches spreading on leaves and stems, then fruit rots from July
Late blight, worst outdoors in warm wet weather
Grow a resistant variety outdoors, water at the base, keep leaves dry, strip and bin (not compost) infected growth as soon as it shows. Greenhouse plants with good ventilation usually escape it.
Clouds of tiny white insects under the leaves in the greenhouse
Glasshouse whitefly
Yellow sticky traps from May, a potassium soft soap spray on the undersides, and the parasitic wasp Encarsia once nights are above 10 °C.
Fuzzy grey mould on stems, leaves or the fruit calyx
Botrytis in a humid, crowded greenhouse
Ventilate daily, remove lower leaves below the first truss, cut out affected tissue, and never wet the foliage.
Fruit splitting as it ripens
A dry spell followed by heavy watering
Water little and often rather than flooding, mulch pots and beds, and pick ripe fruit before rain.
Hard green or yellow shoulders on ripe fruit
Greenback: strong sun and heat with potassium running short
Shade the glass, keep up the high-potash feed, leave a few leaves over each truss.
Holes bored into green fruit
Tomato moth caterpillar
Pick caterpillars off by hand in the evening; remove damaged fruit.
Harvest and rotation
Harvest and storage
Pick when fully coloured and slightly soft, snapping the stalk at the knuckle so the calyx stays on. First fruit 12 to 16 weeks from sowing; a cordon yields 3 to 4 kg over the season, a bush 2 to 3 kg. Keep at room temperature, never in the fridge; ripen green end-of-season fruit indoors in a drawer with a banana, or make chutney and passata.
Rotation and companions
Rotation: potato family (Solanaceae), 3 to 4 year gap, never after potatoes.
Good to knowPinch out side shoots on cordon (indeterminate) types and water consistently, erratic watering causes blossom end rot and splitting.
Growing tomatoes in pots
A cordon needs at least 12 litres (a 30 cm pot); more compost means fewer dry-outs. Bush and tumbling types manage 25 cm pots and baskets. Use a peat-free multipurpose with a third loam-based compost mixed in to hold water, and stand the pot in a saucer from July. In the height of summer a cordon in a 12 litre pot drinks 2 to 3 litres a day, so set a reminder or fit a drip line. Growbags are shallow: cut the bag in half, stand each half on its end and you double the root depth for the same money.
Tomatoes: common questions
When should I stop feeding tomatoes?
When the last truss you intend to keep has set and its fruit is starting to colour, usually early September outdoors and late September under glass. Feeding after that puts goodness into leaf you are about to throw away.
Why are my tomato leaves curling?
Lower leaves that roll upwards along their length in hot weather are normal and harmless; the plant is reducing its leaf area. Curling with mottling or distortion on new growth is a virus or herbicide damage, and those plants come out.
How many trusses should I let a cordon carry?
Four outdoors and six to seven in a greenhouse, then pinch the growing tip two leaves above the top truss. More trusses than that in a UK season just means more green fruit in October.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.