Growing Tomatoes: A Beginner’s Guide to a Bumper Crop

To grow a bumper crop of tomatoes, plant in the warmest, sunniest, most sheltered spot you have, water steadily so the soil is never allowed to swing from bone-dry to sodden, and feed weekly with a high-potassium tomato food once the first fruits set. Choose bush varieties for pots and hanging baskets and leave them alone; choose cordon varieties for a greenhouse or a sunny wall, support them, and pinch out the side-shoots. Everything else is detail, and the detail is below.

This is the general grow-and-care guide: how to choose your plants, where to put them, and how to keep them cropping from July to the first frost. If you want to raise plants from a packet of seed on a windowsill in February, that is a job of its own, and we have a separate step-by-step guide to growing tomatoes from seed. Here we pick up the moment you have young plants in your hands, whether you grew them or bought them.

Choosing plants

Cordon or bush? The one decision that shapes the rest

Every tomato is either a cordon or a bush, and which you grow decides how much work the summer holds. Cordon tomatoes (the seed packet may say “indeterminate”) grow tall on a single stem, need a cane or string to climb, and want their side-shoots pinched out all season. Bush tomatoes (“determinate”) stay low and spreading, need little or no support, and are left to get on with it. The Royal Horticultural Society puts it plainly: bush types are the easiest to grow and need the least maintenance.

So the beginner’s rule is short. If you have a greenhouse, or a warm wall and the patience to tie in a stem and snap off a shoot once a week, grow a cordon and you will get more fruit from less floor space. If you want tomatoes in a pot or a hanging basket on the patio and would rather not fuss, grow a bush and ignore most of the advice about pinching out, because it does not apply to you.

Bush for pots and a quiet life; cordon for a greenhouse and a glut.

Varieties worth growing

For reliable crops, look for varieties carrying the RHS Award of Garden Merit (AGM), which marks plants that have performed well in trials. A few that earn their place:

Match the fruit to the plate before you buy. Cherry types such as ‘Sungold’ are for eating warm off the vine; plum and beefsteak varieties are the ones for sauces and slicing. There is little point growing a beefsteak if what you want is a bowl of something sweet to pick at.

Getting started

From seed or from young plants?

You can start tomatoes either way. Growing from seed is cheaper and opens up hundreds of varieties you will never see as plants, but it ties up a warm windowsill from late February and asks for pricking out and potting on along the way. Buying young plants in spring costs more per plant and limits your choice, but saves two months of nursing. Neither is wrong.

If you are sowing your own, the short version is: sow indoors from late February (for a greenhouse crop) to early April (for outdoors), keep them at around 18°C to germinate, prick out into individual pots once the first true leaves show, and grow them on somewhere bright until they are ready to plant out. For the full method, trays, compost and all, see our guide to growing tomatoes from seed. From here on, we assume you have sturdy young plants ready to go.

Where to grow

Greenhouse, outdoors, pots or grow bags?

Tomatoes will crop in a greenhouse, in open ground, in pots or in grow bags. A greenhouse gives the earliest and largest crop and largely dodges blight, which is the single biggest reason serious growers swear by one. But you do not need a greenhouse to grow good tomatoes, and anyone who tells you otherwise is selling greenhouses.

No greenhouse? Grow on the patio

This is where bush varieties earn their keep. A growing bag costs a pound or two and holds two plants; a 30cm pot of peat-free compost holds one. Stand them against a sunny, sheltered wall, water daily in hot weather, and a single ‘Tumbling Tom’ in a hanging basket will give you cherries all summer with no staking and no side-shoots to worry about. The honest caveat, straight from the RHS: outdoor crops ripen later than greenhouse ones and are more exposed to blight in a wet summer. You will still get tomatoes; you may just get them in August rather than July.

If you would rather not buy bottled tomato food at all, the thriftiest growers make their own from comfrey leaves steeped in water, a free high-potassium feed that does the same job. It smells frankly appalling, which is the price of not paying for a bottle.

In the greenhouse

Under glass, tomatoes grow much as they do outside, with one extra job: shading. In high summer a greenhouse can cook the plants, causing tough skins and patchy ripening, so fit blinds, use shade paint or hang shading fabric, and open the vents on warm days so pollinating insects can reach the flowers. Tapping the trusses when they are in full flower helps the pollen settle.

Planting out

How to plant tomatoes for a strong start

Wait until the danger of frost has passed before planting outdoors, which in most of the UK means late May or early June; under glass you can plant from late April once nights are reliably above about 16°C. Harden plants off first by standing them outside for longer each day over a week or two, so the move outdoors is not a shock.

Then plant deep. Tomatoes are unusual in that the buried section of stem grows new roots, so set each plant so the lowest leaves sit just above the soil; a deeper-rooted plant is a steadier, thirstier, more productive one. In open ground, space plants 45 to 60cm apart in your warmest, sunniest, most sheltered spot, enriched with plenty of garden compost, and put a cane in beside each cordon as you plant, not later when you risk spearing the roots. In pots, one plant per 30 to 45cm pot; in a grow bag, two plants. A mulch of garden compost around plants in the ground keeps the moisture even and saves watering, though leave a gap around the stem so it does not rot. Avoid planting tomatoes in the same patch of ground two years running, which lets soil-borne disease build up.

Watering & feeding

Watering: steady wins the crop

More tomato crops are spoiled by erratic watering than by anything else. The single rule is consistency: keep the soil or compost evenly moist and never let it swing from parched to flooded. Plants in pots and grow bags dry out fast and may need watering daily in hot weather, and twice on the hottest days. Curling leaves are usually a sign the plant is thirsty.

The reason this matters so much is physical. When a dry plant is suddenly soaked, the fruit takes up water faster than its skin can stretch, and it splits. The same swings cause blossom end rot, the sunken brown patch on the base of the fruit. An RHS trick worth borrowing: sink a 15cm pot into the ground next to each plant and water into that, so the water goes straight to the roots and does not sit around the neck of the stem, where it can cause rot.

Feeding for flavour and a heavy crop

Tomatoes are hungry plants, but they want the right food at the right time. Until the first fruits set, they need little extra; feed too early and you get a forest of leaf and few tomatoes. Once the first fruits start to swell, feed with a high-potassium liquid tomato food. The RHS suggests every 10 to 14 days for container plants; many growers, and Gardeners’ World, feed weekly once flowering is in full swing. Potassium is what drives flowering and fruiting, which is why ordinary plant feed, higher in nitrogen, is the wrong bottle for the job.

Training the plant

Pinching out side-shoots and supporting the plant

This section is for cordon growers; if you are growing a bush variety, you can skip it and let the plant sprawl. On a cordon, the plant naturally throws out side-shoots: small shoots that appear in the V where a leaf branch meets the main stem. Left alone they grow into a tangle of leafy stems that carry little fruit. Pinch or snap them out while they are small, every time you water, so the plant pours its energy into the trusses on the main stem instead of into spare greenery.

Tie the main stem loosely to its cane as it climbs, or wind it around a vertical string anchored under the rootball. Then comes the part beginners forget: stopping the plant. When a cordon has set four trusses outdoors, or seven under glass, pinch out the growing tip two leaves above the top truss. This is not optional in a British summer. The season is too short to ripen more than that, so an unstopped plant merely makes flowers that never become tomatoes, at the expense of the fruit already on the vine.

Common problems

Blight, blossom end rot and splitting

Three problems account for most tomato disappointments, and all three are easier to prevent than to cure.

Tomato blight

Blight is the big one. It is an airborne fungal disease, the same family that causes potato blight, and it strikes in warm, wet weather, turning leaves brown and rotting the fruit. It mostly affects outdoor plants; a greenhouse largely keeps it out because the foliage stays dry. There is no home cure once it takes hold: remove and bin affected plants (do not compost them) to stop the spread, and in a bad blight summer, pick any sound fruit to ripen indoors. Growing under glass, or choosing a blight-resistant variety such as ‘Crimson Crush’, is the only real defence.

Blossom end rot

Blossom end rot shows as a dark, sunken, leathery patch on the bottom of the fruit. It looks like a disease but it is a watering fault. The plant cannot move enough calcium to the developing fruit when its water supply keeps swinging, so the tissue at the far end collapses. It is most common in pots and grow bags, which dry out fastest. The fix is not to dose the soil with calcium but to water steadily and consistently; even moisture solves it.

Splitting

Split skins have the same root cause: a dry plant, suddenly watered, swells faster than its skin can stretch. Steady watering prevents it. Split fruit is still perfectly good to eat straight away, so pick and use it rather than leaving it to spoil on the vine.

Harvest

Harvesting and ripening the last of the crop

Tomatoes ripen from midsummer onwards, cherries first and beefsteaks last, greenhouse plants ahead of outdoor ones. Leave fruit on the plant to ripen fully if you can, because the flavour keeps improving to the end; pick each tomato with its stalk still attached, every few days, as soon as it is fully coloured. Keep ripe tomatoes at room temperature, not in the fridge, which turns the texture mealy.

When the first cold nights arrive and a tray of green tomatoes is still on the vine, do not waste them. Lift whole outdoor plants and lay them on straw under a cloche to finish, or pick the green fruit and bring it indoors. The old trick works: put green tomatoes in a drawer with a ripe banana, whose ethylene gas brings them on in a week or so. Anything that stubbornly stays green makes excellent green tomato chutney, which is the proper end to the tomato year.

Growing tomatoes: your questions answered

When should I plant tomatoes outside in the UK?

Plant tomatoes outdoors once all danger of frost has passed, which in most of the UK means late May or early June. Harden the plants off over a week or two first. Under glass you can plant from late April, once nights are reliably above about 16°C.

How often should I water tomato plants?

Water often enough to keep the soil or compost evenly moist and never let it dry out completely. Plants in pots and grow bags may need watering once a day in warm weather and twice on the hottest days; plants in open ground need a good soak two or three times a week. Consistency matters more than volume, because erratic watering causes splitting and blossom end rot.

When and how do I feed tomatoes?

Start feeding once the first fruits begin to set, not before. Use a high-potassium liquid tomato food, every 10 to 14 days for plants in containers, or weekly once flowering and fruiting are in full swing. High potassium drives fruiting; ordinary high-nitrogen feed gives you leaf at the expense of tomatoes.

What are side-shoots and do I pinch them out?

Side-shoots are the small shoots that grow in the V between the main stem and a leaf branch on cordon tomatoes. Pinch or snap them out while small so the plant puts its energy into fruit. Bush tomatoes do not need their side-shoots removed; leave them to sprawl.

Can I grow tomatoes without a greenhouse?

Yes. Tomatoes crop well outdoors in pots, grow bags or open ground in a warm, sunny, sheltered spot. Bush varieties in pots or hanging baskets are the easiest no-greenhouse option. The trade-off is that outdoor crops ripen a little later and are more at risk of blight in a wet summer.

Why are the bottoms of my tomatoes going black?

That is blossom end rot, a sunken dark patch caused by inconsistent watering rather than disease. The plant cannot move calcium to the fruit when the water supply keeps swinging. Water steadily and evenly, especially in pots and grow bags, and new fruit will form cleanly.

How many trusses should a tomato plant have?

Stop a cordon by pinching out the growing tip after four trusses outdoors or seven under glass, leaving two leaves above the top truss. In a UK summer there is not enough warmth and light to ripen more than that, so an unstopped plant wastes its energy on fruit that never ripens.

Related gardening guides

• Growing Tomatoes From Seed: A Step-by-Step UK Guide — the sowing and propagation detail.
• Raised Beds for Vegetables — the easy way to grow your own, tomatoes included.
• The Best Trailing Plants for Baskets and Window Boxes — where tumbling cherry tomatoes belong.
• Small Garden Ideas — making the most of a tiny plot.
• What to Plant in June and July — the month-by-month family gardening pillars.

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Written by Linda Garrould. Updated 15 June 2026. Horticultural detail checked against Royal Horticultural Society guidance.