Is it too late to plant tomatoes? In the UK, the honest answer for early August is: too late to start them from seed for this year, but not necessarily too late to buy and plant an established plant if you have a greenhouse or a warm, sheltered spot. Tomatoes need a long, warm season to crop, and sowing seed now leaves nowhere near enough time for plants to grow, flower, and ripen fruit before the cold arrives. But a garden-centre plant already in flower, given warmth and shelter, can still give you a modest late crop of small or cherry tomatoes. So the real answer depends on whether you mean from seed or from a plant, and on what growing space you have. Let me walk you through exactly what is realistic now, and what to do instead if you have genuinely missed the window.

I have grown tomatoes for over twenty years on my Oxfordshire plot, and I have made this exact mistake, hopefully sowing seed far too late one hopeful July and getting nothing but leggy plants and green fruit that never ripened. So I understand the worry behind the question. Let me give you a straight, realistic answer rather than false hope, because knowing when to cut your losses and plan for next year is part of being a good gardener too.

From Seed: Yes, It Is Too Late

Let us be honest about sowing tomato seed. By August, it is too late to sow tomatoes from seed in the UK and expect a crop this year. Tomatoes need roughly five to six months from sowing to harvest, so seed sown now would not produce ripe fruit until well into the autumn or winter, long after the warmth and light have gone. You would end up nursing small, struggling plants indoors with little or nothing to show for it.

The sensible sowing window for tomatoes in the UK is late winter to early spring, typically February to April, so they are ready to plant out after the last frost. If you are reading this in August and thinking about seed, the honest advice is to wait and sow at the right time next year, which is covered fully in when to plant tomatoes. Sowing now is one of those hopeful moves that almost always disappoints.

From a Plant: Maybe, With Shelter

Buying an established plant is a different matter, and here there is a bit more hope. If you can still find a healthy tomato plant already in flower or carrying small fruit at a garden centre, and you have a greenhouse, conservatory, or a very warm, sheltered, sunny spot, it is worth a try. The plant has already done the slow early growing, so it only needs to ripen the fruit it sets, which a warm late summer can just about manage, especially with quick-ripening cherry varieties.

Be realistic about the crop, though. You are looking at a modest handful of fruit rather than a glut, and outdoors without shelter your chances drop sharply as the nights cool. Under glass, or on a warm windowsill, the odds are much better. Give the plant the same care as any tomato, steady watering and a high-potash feed, as in caring for tomato plants, and you may be pleasantly surprised by a late picking.

Why Tomatoes Need So Long

It helps to understand why the window matters so much, because it is not arbitrary. Tomatoes are warm-season plants that originated in a much hotter climate than ours, and they need a long stretch of warmth and light to grow, flower, set fruit, and then ripen it. In the UK our warm season is genuinely short, which is why timing is tighter here than in warmer countries. The RHS guide to growing tomatoes sets out the full timeline. Miss the early start and there simply are not enough warm, bright weeks left in the year to see fruit through to ripe.

This is also why so many UK tomato problems, from poor fruit set to fruit that will not ripen, come down to not enough warmth and time. Understanding your season, and your local frost dates, is the key to getting tomatoes right, and it is why the early sowing window is worth respecting rather than pushing your luck with a late one.

If You Have Green Tomatoes Now

A related worry at this time of year is not late planting but late ripening: you have plants covered in green fruit and you are wondering if they will ever turn red before the cold. The good news is that even if the season runs out, green tomatoes are not wasted. You can ripen them indoors on a windowsill or in a drawer with a banana, whose ethylene gas speeds ripening, or turn a glut of stubborn green ones into chutney.

So if your existing plants are racing the cold, do not panic. There is a full method in how to ripen green tomatoes, and it means a late or slow year still gives you a usable crop. This is a very different situation from planting late, and a much more hopeful one, since the fruit already exists and just needs coaxing to ripen.

What You Can Plant Instead

If it really is too late for tomatoes this year, the cheering news is that August is far from the end of the growing season, and plenty of other crops can still go in now for an autumn or even winter harvest. Quick salad leaves, lettuce, radishes, spring onions, and oriental greens all have time to crop before winter, and hardy crops like spinach and chard sown now will give you pickings into the colder months. It is a good moment to fill the gap the tomatoes cannot.

There is a full rundown of what still works this late in is it too late to plant vegetables and the specifics in what to sow in August. Turning your attention to these crops is far more rewarding than nursing a doomed late tomato, and keeps your garden productive right through to the end of the year. The quick, easy ones are covered in easy vegetables to grow.

Getting Ahead for Next Year

If the honest answer of too late for tomatoes has landed with a thud, the best cure is to channel that keenness into next year, when you can grow them properly from the start. Make a note now to sow your tomato seed in February or March, so your plants are strong and ready to go out after the last frost. Getting the timing right from the beginning is the single biggest factor in a good tomato year, far more than any clever trick later on, something the wider planting calendar helps you plan.

It is also worth spending the autumn and winter improving the soil where your tomatoes will go, since rich, healthy soil makes for stronger plants, as covered in improving your garden soil. Then come spring you will be ready to grow tomatoes the right way, following how to grow tomatoes from sowing to harvest. A little patience now sets up a far better crop than any rushed late planting ever could.

Growing Tomatoes in Containers Next Time

One thing worth planning for, if space or a short season is your worry, is growing tomatoes in pots next year, since containers let you start plants in a sheltered spot and move them to catch every scrap of warmth and sun. Pot-grown tomatoes can be brought under cover on cold nights and out into the sun by day, which extends their season at both ends and is a real advantage in our climate. It is one of the best ways to get a reliable crop in a tricky British summer.

There is guidance on this in growing vegetables in pots, and it applies well to tomatoes. Combined with an early start and a warm spot, container growing gives you the best possible chance of a good crop, and sidesteps the whole is it too late worry by getting you off to a strong, early, movable start. It is planning rather than panic, which is where good tomato growing always begins.

The Honest Answer

So, is it too late to plant tomatoes? From seed in August, yes, and it is kinder to tell you that plainly than to send you off on a doomed sowing. From an established plant with warmth and shelter, you have a slim but real chance of a small late crop, especially with cherry varieties under glass. And if you already have green fruit, you are not too late at all, just ripen them indoors. Match your effort to what is genuinely possible and you will not waste a season on false hope.

Above all, do not be disheartened. Every gardener has looked at the calendar in dismay at some point, and the answer is nearly always to plant something else now and get the timing right next year. Turn to the crops that still have time, plan your tomatoes properly for spring, and you will be a better and happier gardener for it. There is always something you can grow, whatever the month, as the wider tomato growing guides show.

Is It Too Late to Plant Tomatoes: Frequently Asked Questions

A Sensible Place to Start

If you are wondering whether it is too late to plant tomatoes, the honest answer is: too late from seed this year, but worth a try from an established plant if you have a greenhouse or a warm, sheltered spot and are happy with a small crop. And if you already have green fruit on the plant, you are not too late at all, simply ripen them indoors.

If it really has passed for tomatoes, do not waste the season sulking. Sow quick salad leaves and hardy greens now for an autumn crop, improve your soil over winter, and plan to sow your tomatoes in February or March next year. Get the timing right from the start and you will grow a far better crop than any rushed late planting could ever give you.

Growing tomatoes in the UK is more forgiving than most people think, and they are not the divas their reputation suggests. In more than twenty years of growing them in Oxfordshire I have come to believe that most tomato failures are not bad luck at all. They come down to timing, warmth, steady watering, and paying attention at a few key moments. Get those roughly right and a couple of plants will keep a kitchen in tomatoes from July well into autumn. Get the timing wrong and they will sulk all season, however much you fuss over them. This page ties the whole thing together.

The reason tomatoes get a name for being tricky is that people mostly see them when they are struggling. Seedlings stretch and flop on a windowsill in March, young plants stall for a fortnight after going outside, leaves yellow, flowers drop off without setting, and then the first decent truss splits open after a wet weekend. None of that is the plant being difficult for the sake of it. It is a warm-season crop being asked to cope with a British spring, and British springs are not kind to anything that wants steady heat.

That is really the whole secret. A tomato does not want a clever trick or an expensive gadget. It wants the right thing at the right stage, in the right order, and it will tell you very clearly when it is not getting it. Once you learn to read that, growing them stops feeling like a gamble. If you want the wider edible-growing basics alongside this, they sit in How to Grow Vegetables in the UK, and the RHS tomato guide is worth a look too. Consider this page the map of the whole tomato cluster on the site, with the detailed guides linked at each stage.

Why Tomatoes Behave Differently in the UK

Tomatoes get lumped in with lettuce, peas and beetroot as a standard beginner crop, and I think that is where a lot of the disappointment starts. They are nothing like those. Lettuce forgives a cold snap. A tomato remembers it.

They are warmth-loving plants that need a long enough run to build up before they can crop heavily, and in this country that run is shorter and bumpier than they would choose. The classic mistake, the one I made for years, is trusting the look of a nice week in May. The sun is out, the days feel warm, so out go the plants. Then the nights are still dropping to five or six degrees, the soil is colder than it looks, and a young plant that moved outside too soon just stops. It rarely dies. It simply loses a fortnight of momentum that it never quite gets back, and it fruits later and less because of it.

So I have come to treat tomatoes as a crop of stages rather than a crop you plant and wait on. A strong start, a patient planting-out, steady watering once they settle, and a bit more hands-on attention through summer than most vegetables ask for. That is not a reason to leave them to the experts. It just means they pay you back for understanding them rather than rushing them.

The Main Stages of Growing Tomatoes

The easiest way to keep tomatoes on track is to think in stages, because almost every problem you meet later can be traced back to something that slipped earlier on. It runs roughly like this: start your seeds or buy young plants at the right time, grow those young plants on in real warmth and good light so they stay stocky, plant them out only when conditions are genuinely ready for them, then support and care for them steadily through the summer while heading off the common problems before they cost you fruit. Disease sits at the far end of that chain, and the earlier you learn to spot it, the calmer the whole thing feels.

None of those stages is hard on its own. The skill is not letting one slide into the next while it is still wrong. A weak seedling planted out on time is still a weak plant, and a lovely stocky plant set out three weeks too early will check anyway. Get the sequence right and the plant more or less grows itself.

Getting the Timing Right

If I could fix one thing for most beginners it would be timing, because it decides more than any other single choice. I know the pull to sow early. Those first tomato seeds going into compost in late winter feel like the season starting, and I have sown far too soon plenty of times out of pure impatience.

The trouble is that a tomato sown too early has nowhere sensible to go. It germinates, it grows, and then it sits on a windowsill for weeks waiting for the weather to catch up, just as sowing too late leaves no time to crop, which raises the question of whether it is too late to plant tomatoes, stretching towards weak spring light and getting leggier and floppier by the day. By the time it is safe to plant out you have a tired, over-long plant instead of a fresh, eager one. Sow too late, on the other hand, and you simply run out of summer at the far end. What you are aiming for is a plant that hits its stride exactly when the weather does, not weeks before. The full schedule lives in When to Plant Tomatoes in the UK, and if your seedlings have already gone long and pale, Why Tomato Seedlings Go Leggy in the UK explains how to rescue them.

Where Tomatoes Grow Best

Tomatoes want as much light and warmth as you can honestly give them, and a spot out of the wind. In practice, in a UK garden, that usually means a greenhouse, a sunny patio against the house, the shelter of a warm wall, or the hottest bed you have. Light does most of the heavy lifting, but shelter matters more than people expect. A bright but windy corner will still hold a plant back, because wind steals warmth and knocks it about just when it is trying to settle.

I see this every year in my own garden. Two plants of the same variety, sown the same day, potted on together, can end up looking like different crops purely because of where they landed. The one tucked into a warm, still corner by the back wall romps away. The one only a few steps out into the open catches the wind, loses heat overnight, and never really looks comfortable. Same plant, same care, wildly different result, and the only variable is the spot. Containers can be brilliant for exactly this reason, because they let you put a tomato in the best square metre you own, though they do dry out faster and want closer watching.

Tomatoes in Pots, Beds, and Greenhouses

One of the nicest things about tomatoes is how adaptable they are. I have grown them in a greenhouse, in big pots and grow bags on the patio, in raised beds, and in open ground against a south-facing fence, and every one of those can give you a proper crop if the light and warmth are there.

Each has its own character, though. A greenhouse gives the most reliable warmth and the best protection from our wetter spells, which usually means an earlier and steadier crop, and it keeps blight off the plants far more often than not. Pots and grow bags win on flexibility and are the answer when your only sunny spot is paving, but they are thirsty and unforgiving if you let them dry out. Beds and borders can be excellent, but only where the site is genuinely sunny and the soil drains rather than sits wet. If you are leaning towards containers, it is worth reading Can You Grow Vegetables in Pots in the UK? and Best Vegetables to Grow in Pots in the UK before you commit.

Why Tomato Plants Need Ongoing Care

Here is where I want to head off a common worry, because a lot of people assume tomatoes need constant fiddling and put themselves off. They do not need panic. What they need is consistency: enough warmth, enough light, sensible feeding, decent support, and watering that does not swing from bone dry to flooded. When those basics are right, care becomes genuinely light work.

What they are not, though, is a plant-it-and-forget-it crop. Once a cordon tomato gets going it grows fast, and it needs tying in, the odd side shoot pinched out, a steady drink, feeding once the fruit starts, and a proper look-over every few days. That last one is the bit people skip and then regret. Half the tomato disasters I have seen, my own included, were quietly building for a week before anyone noticed, and would have been nothing much if caught early. If you want the practical, step-by-step side of all that summer maintenance, it lives in How to Care for Tomato Plants in the UK.

What Usually Goes Wrong With Tomatoes

Tomato problems love to look dramatic. A leaf yellows, a truss of flowers drops overnight, a ripe fruit splits from top to bottom, and it feels like disaster. In truth almost all of it traces back to a short list of causes, and once you know the list, the drama drains out of it.

The usual suspects are poor early light giving you weak seedlings, a cold start or planting out too soon, watering that lurches between extremes, feeding that is either absent or overdone, a spot that is too exposed or too shady, and stress during flowering and fruit set. Notice that most of those are conditions, not diseases. That is the useful part. Instead of treating every yellow leaf as a fresh catastrophe, you start asking what the plant has been put through over the last couple of weeks, and the answer is usually sitting right there. For the wider troubleshooting side, Common Tomato Problems in the UK walks through the symptoms one by one.

Why Watering Matters So Much With Tomatoes

If one thing causes more tomato grief than anything else, it is watering, and specifically inconsistent watering. Tomatoes do not want a daily splash whenever the surface looks dry, and they very much do not want to swing between parched and drowned. They crop best when the moisture stays reasonably even, so the plant never gets a shock in either direction.

The year that taught me this properly, I went away for a long weekend in a dry spell, came back to plants that had been bone dry for days, gave them a good soaking to make up for it, and then it rained hard for two days on top. Within a week half the ripening fruit had split, and the ones that did not split went down with blossom end rot, that sunken dark patch on the base that comes from calcium not reaching the fruit when watering is erratic. It was not a pest and it was not a disease. It was me, or rather the swing from dry to flooded that I had caused. Split skins, poor flavour, dropped flowers, blossom end rot and weak, uneven growth all trace back to that same instability, and it hits containers hardest, because a pot dries out and heats up far faster than open ground.

Feeding Tomatoes Without Overdoing It

Tomatoes are hungry compared with most leafy crops, but feeding still wants a bit of judgement rather than a heavy hand. The assumption that more feed means more tomatoes is the most stubborn myth in the whole business, and it simply is not true. Feeding works when the plant is already growing in decent conditions. If the roots are cold, the watering is all over the place, or the plant is stressed for some other reason, another dose of feed will not fix any of it, and it can make things worse.

Overfeed with the wrong thing, especially something too high in nitrogen, and you push out masses of lush leaf at the expense of actual fruit. What you generally want once the first truss has set is a high-potash liquid feed, the sort sold as tomato food, given at the strength on the bottle rather than a splash more for luck. I keep a bottle of high-potash tomato feed on the go from midsummer and stop guessing. Think of feeding as support for a plant that is already doing well, not a rescue for one that is not.

Flowers, Fruit Set, and Why Tomatoes Sometimes Disappoint

One of the sneakier ways tomatoes let you down is looking perfectly healthy while barely cropping. The plant is green, tall and covered in flowers, so you assume a glut is coming, and then the fruit set is thin or the harvest is far lighter than the plant seemed to promise. This one catches a lot of people out precisely because nothing looks wrong.

It usually comes down to temperature stress, irregular watering, poor ventilation in a stuffy greenhouse where the pollen goes tacky and will not shift, a plant that was checked earlier in the season and never fully recovered, or feeding that pushed leaf over fruit. The lesson I hold on to is that flowers are a promise, not a crop. A tomato only carries that promise through to a full harvest when the conditions behind it are right, so if a plant is flowering freely but setting poorly, the fix is almost always in the growing conditions rather than the flowers themselves.

Common Tomato Problems in the UK

Tomatoes wear their troubles on the outside, which is genuinely helpful once you learn to read the signs rather than panic at them. The problems that come up most often in UK gardens are:

• yellowing leaves
• leggy seedlings
• flowers dropping and poor fruit set
• fruit splitting
• blossom end rot
• slow ripening
• plants staying weak after planting out

Hardly any of these are random. Each one is the plant flagging that something in its recent conditions has been off, and reading them that way turns troubleshooting from guesswork into detective work. When your plants are misbehaving and you want to work out why, Common Tomato Problems in the UK takes each symptom in turn.

Tomato Diseases in the UK

Disease is part of growing tomatoes here, and there is no point pretending otherwise in a climate that manages to be warm and damp at the same time. The one that breaks hearts is blight, the same disease that flattens potatoes, and it tends to arrive on the wind during a warm, wet spell in late summer. I lost a whole outdoor row of Gardener’s Delight to it in one soaking August, the leaves going from healthy to brown mush in the space of a few days, and there is not much you can do once it takes hold outside.

Two things have changed how I handle it. The first is that a greenhouse keeps blight off far more reliably than open ground, simply by keeping the leaves dry. The second is blight-resistant varieties. Something like Crimson Crush is not fully immune, and it can still show a little on the leaves in a bad year, but it usually grows straight through and crops anyway where an ordinary variety would be finished. On an exposed outdoor plot that has changed outdoor tomatoes from a gamble into something worth doing again. Not every mark on a leaf means blight, mind, and grey mould and various rots turn up too, so it pays to know what the common ones actually look like before you reach for the worst conclusion. The BBC Gardeners’ World guide has clear photos of blight symptoms, and the full rundown for the site is in Tomato Diseases in the UK, with a dedicated page on tomato blight if that is what you are facing.

Why Tomatoes Are Still Worth Growing

After all that talk of stress, timing and blight, you would be forgiven for wondering why anyone bothers. I bother because when a tomato is good, nothing from a shop comes close. The variety I would never be without is Sungold, a small orange cherry that is so sweet picked warm off the vine that half of mine never make it as far as the kitchen. That flavour is the whole point, and it is a thing supermarket tomatoes, bred to survive a lorry rather than to taste of anything, simply cannot give you.

There is a quieter reason too. Tomatoes teach you more than almost any other crop in one season. Timing, warmth, support, watering, feeding, and the habit of actually looking at a plant and reading it all come together in this one hungry, dramatic, generous thing. Learn to grow tomatoes well and you find you have quietly become a better gardener across the board.

How Tomatoes Fit Into a UK Vegetable Garden

Tomatoes belong firmly to the warm-season half of the gardening year, in with the crops that hate a cold start and want settled conditions before they will do anything useful. That puts them alongside courgettes, cucumbers, peppers and chillies and beans in the summer garden, rather than among the early spring sowings like broad beans or the first peas.

Holding that bigger picture in your head heads off the commonest tomato mistake there is, which is expecting them to be powering along while the season has barely woken up. They are late risers by nature, so plan the garden around that and they slot in neatly instead of frustrating you every April.

What a Sensible Tomato Plan Looks Like

A good tomato plan is honestly quite dull, and that is exactly why it works. Start them at the right time, grow on sturdy young plants in strong light, and plant out only when conditions are genuinely ready rather than when you are impatient. From there, keep the watering steady, feed sensibly once the fruit sets, support the plants properly, and look them over often enough to catch small problems while they are still small. That is more or less the entire job.

Tomatoes do not reward fuss, and they punish neglect. What they respond to is a simple, steady routine run by someone who is paying attention. Do that and they are one of the most generous things you can grow in a small British garden.

Where to Go Next in the Tomato Cluster

This is the hub page, so the best thing to read next depends on where you are. If you are still planning and want the sowing and planting dates, start with When to Plant Tomatoes in the UK. If you already have plants and want the full step-by-step, go to How to Grow Tomatoes in the UK. If they are growing and you want help with watering, feeding, support and upkeep, How to Care for Tomato Plants in the UK is the one you want. And if something looks wrong and you are not sure why, work through Common Tomato Problems in the UK or, if you suspect disease, Tomato Diseases in the UK.

Tomato FAQs

A Sensible Place to Start

If you want better tomatoes in the UK, stop thinking in quick fixes and start thinking in stages. Get the timing right, give the young plants enough light, and wait until conditions are truly ready before planting out. After that it is just a matter of keeping the season steady, with proper support, sensible feeding, and watering that does not lurch from one extreme to the other.

Tomatoes are not delicate. They are honest. They respond clearly and quickly whenever something important is out of balance, which feels like a curse when you are new to them and turns into a gift once you learn to listen. Once you do, they stop being a worry and become one of the most satisfying things in the garden to grow and, when something does go wrong, to put right.

When to plant tomatoes in the UK splits into two jobs that people often muddle together. Sow the seed indoors between late February and early April, then plant out from mid May in a greenhouse and from late May into early June outdoors, once the frosts have finished. Sow too early and you spend April nursing pale, stretched seedlings that never recover. Plant out too early and one cold night undoes months of work. The dates below are the ones I use in Oxfordshire, with adjustments for wherever you garden.

Why Tomatoes Punish an Early Start

The urge to sow tomatoes in January is almost irresistible. The seed packets are sitting there, the catalogues have been arriving since Boxing Day, and sowing something feels like the season finally starting. I have given in to it more than once and it has never once paid off.

The problem is not germination. Tomato seed will come up happily in February on a warm windowsill. The problem is what happens next. A seedling needs strong light to build a stocky plant, and in February and early March there simply is not enough of it in a British house. The plant stretches towards the window, the stem goes thin and pale, and by the time it is warm enough to go outside in late May you are holding a leggy, exhausted thing that has been living in a pot for four months. A plant sown in late March, into brightening days, will overtake it within a fortnight of planting out and crop earlier. That is not a theory, it is the same lesson I have relearned in three separate years.

Then there is the frost. Tomatoes are killed outright by it, not merely checked, and even a cold night at three or four degrees with no frost at all will stall a young plant for a fortnight. Every date on this page exists to keep your plants away from those two problems.

Sowing Tomato Seeds Indoors

Late February to early April is the window, and where you land inside it depends on where the plants are going. If you have a heated greenhouse, sow from late February. For an unheated greenhouse, mid to late March. For outdoor tomatoes, late March into early April is plenty, and I would rather sow in the first week of April than the first week of March.

Tomato seed germinates best between about 18C and 24C, which is warmer than most rooms. A seed tray with a propagator lid holds that warmth and humidity steadily, and it is the difference between patchy germination and a full tray. An airing cupboard works too, as long as you check daily and move them to the light the moment the first shoot appears. Leave them in the dark a day too long and they stretch beyond saving.

Variety matters more than most beginners expect. Cherry types are far more forgiving of a British summer than big beefsteaks, which often run out of season before they ripen. Sweet Million tomato seeds are a good starting point, heavy cropping and reliable, and a plant or two will keep a household in cherry tomatoes from July. If you want the fuller picture on varieties and growing method, that sits in my guide to growing tomatoes in the UK, and the RHS tomato guide is a good second opinion on sowing depth.

Potting On and Keeping Plants Stocky

Once seedlings have their first pair of true leaves, move them into individual pots. Tomatoes are unusual here and it is worth knowing: you can bury the stem right up to the lowest leaves and the buried section will grow roots. That is the single best trick for rescuing a seedling that has already gone a bit leggy, and it is why tomatoes forgive that mistake when most crops do not.

After that the job is light and cool rather than warm and dim. A slightly cooler, very bright spot produces a short, thick-stemmed plant. A warm dark corner produces a tall weak one. If your only window faces north, a sheet of kitchen foil propped behind the tray bounces a surprising amount of light back and stops the plants leaning so hard. Turn the pots every couple of days as well. If yours have already gone tall and floppy, why tomato seedlings go leggy covers how to bring them back.

Greenhouse or Outdoors Changes Everything

A greenhouse buys you roughly two to three weeks at each end of the season, and in a British summer that is the difference between a decent crop and a glut. Greenhouse plants can go into their final position from mid May in most years, or early May with fleece to hand. They also stay dry, which matters enormously because blight arrives on warm wet weather and wet leaves are how it takes hold.

Outdoor tomatoes wait for the frosts to finish properly, which for most of the country means the last week of May into the first week of June. If you have left it later than that, it is worth checking whether it is too late to plant tomatoes. They want the warmest, most sheltered spot you have, ideally against a south-facing wall that holds heat overnight. Grow a blight-resistant variety outdoors if you can, because in a wet August an ordinary outdoor tomato is at the mercy of the weather. If you are unsure when your own frosts finish, the last frost date checker will give you a date for your postcode rather than a national average.

Soil Temperature, the Thing Nobody Checks

Air temperature is what everyone watches, and soil temperature is what actually decides whether a newly planted tomato gets going. You want soil at about 12C or above before planting out. Cold soil in May is why plants sit there doing nothing for three weeks after an apparently perfect planting day.

Warming the bed is easy and worth the effort. A sheet of black plastic or a couple of cloches over the planting area for a fortnight beforehand lifts the soil temperature noticeably. Wet soil is the other half of the problem, since waterlogged ground stays cold and rots roots, so if your ground sits wet it is worth improving the drainage or planting into raised beds and pots instead. Working plenty of compost into the soil the autumn before does both jobs at once.

Month by Month

February

Only sow now if you have a heated greenhouse to move plants into. Otherwise use the month to order seed and clean pots, and leave the sowing alone.

March

The main sowing month for greenhouse tomatoes, and a good time to start outdoor ones in the north where the season runs late. Sow indoors in warmth, then get the seedlings into strong light immediately.

April

The last sensible sowing window for outdoor plants, and the month for potting on. Towards the end of April, greenhouse plants can start moving into their final positions if the weather is kind. Do not be tempted to put anything outside yet.

May

The month everything happens, and the month that catches people out. Greenhouse tomatoes go in from mid May. Outdoor plants get hardened off across the last two weeks and planted out at the very end of the month at the earliest. Watch the forecast rather than the calendar, because a warm week in early May means nothing about the nights that follow it. There is more on the wider May jobs in what to plant in May.

June

The safe month for outdoor planting everywhere in the UK, and not late at all. Plants going out in the first half of June will crop perfectly well. Early June is also when you start tying in and pinching out side shoots, which is covered in June gardening jobs.

Where You Live Changes the Dates

Everything above is written for the middle of England. In the South West and along the south coast, mild winters and early springs mean you can usually plant out a week or two earlier, and outdoor tomatoes are genuinely reliable. London and the South East run similarly early, with the added help of the heat that cities hold overnight.

Across the Midlands the standard dates apply as written. In northern England, push planting out into early June and lean towards a greenhouse or a very sheltered wall. In Scotland, outdoor tomatoes are hard work outside the mildest coastal spots, so a greenhouse or polytunnel is close to essential, and planting out before the middle of June is asking for trouble. Altitude and local shelter matter as much as latitude, and a neighbour who has gardened the same street for twenty years is a better guide than any map.

Hardening Off Properly

This is the step people skip when they are impatient, and it is the one that costs them. A tomato raised indoors has soft growth and no defences against wind or direct sun, and moving it straight outside scorches the leaves and shocks the plant badly.

Give it a fortnight. Start with an hour or two outside in a sheltered spot, build up over the days, and bring the plants in every night for the first week. In the second week they can stay out overnight if there is no frost forecast. I lost most of a batch years ago by doing this over a single sunny weekend, and the plants that survived cropped weeks behind the ones I did properly the following year. The full hardening off method applies to every tender crop, not just tomatoes.

Planting Out: Depth, Spacing and Support

Choose a mild overcast day rather than a hot bright one, and water the plants an hour beforehand. Plant deep, burying the stem up to the first leaves as you did when potting on, because those buried roots make a sturdier and more drought-resistant plant.

Give them room. Cordon tomatoes want about 45cm between plants, bush types more like 60cm, and greenhouse rows want 45 to 60cm with space to walk. Crowding is a false economy: airflow drops, humidity rises, and you invite exactly the fungal problems described in tomato diseases in the UK. Put the support in on planting day rather than later, since driving a cane in beside an established plant tears through the roots. Tomato canes or plant stakes do the job for cordons, and a truss of fruit is heavier than people expect.

The Mistakes That Cost a Crop

Four things account for most tomato disappointment, and all of them are about timing rather than skill. Sowing in February and keeping plants indoors for four months. Planting out during a warm spell in early May, then losing them to a cold night ten days later. Rushing the hardening off. And planting into cold, wet soil that has not warmed through, which stalls a plant for weeks and can rot it outright.

Notice that none of those is about feeding, pruning or watering. Those matter later, but they cannot rescue a plant that started badly. If your plants are already in and misbehaving, work through common tomato problems, and if they are flowering without setting fruit, tomato plants not producing fruit covers that specifically.

Tomatoes in Pots and Raised Beds

Containers give you a genuine timing advantage because compost warms faster than open ground, and pots can be moved into shelter or dragged against a wall when a cold night threatens. On a patio you can often plant a week or so earlier than in a bed.

Go large. One plant per 30cm pot at the very least, and bigger is better. The small pots people use are the reason so many container tomatoes wilt daily and suffer blossom end rot, since erratic watering stops the plant taking up calcium. Raised beds sit neatly in between, warming earlier than open ground while holding moisture better than a pot. Whichever you choose, consistency of watering matters more than the container itself.

When Your Tomatoes Will Be Ready

Count roughly 16 to 20 weeks from sowing to the first ripe fruit. In practice, a March sowing planted out in late May gives greenhouse tomatoes from mid July and outdoor ones from late July or early August, running on until the first frosts.

Planting date shifts that whole window. Greenhouse plants in by mid May can be picking in early July. Standard late May planting brings the main crop through August and September. A late June planting still crops, but everything arrives in September when the light is going, and you will finish the season with more green fruit than red. That is not a disaster, since green tomatoes make excellent chutney, but it is worth knowing before you decide to delay.

Helping Them Ripen Before the Season Ends

By late August, stop the plants. Pinch out the growing tip two leaves above the top truss so the plant stops making new growth and puts everything into the fruit it already carries. Remove the lower leaves to let light and air at the trusses, and cut back on watering slightly, which concentrates flavour.

If frost is forecast and there is still green fruit outside, pick everything and bring it in. A banana in the bowl or the bag speeds it along, and any that refuse to turn go in the chutney pan. BBC Gardeners’ World has more on end-of-season care if you want another view.

Quick Reference

• Sow indoors: late February (heated greenhouse) to early April (outdoor plants)
• Pot on: when the first true leaves appear, burying the stem deep
• Harden off: two weeks before planting out
• Plant in a greenhouse: mid May onwards
• Plant outdoors: late May to early June, after the last frost
• Soil temperature: about 12C or warmer before planting out
• First ripe fruit: roughly 16 to 20 weeks from sowing

If you are planning the rest of the plot around these dates, the full vegetable planting calendar puts tomatoes alongside everything else going in through spring.

When to Plant Tomatoes in the UK: Frequently Asked Questions

A Sensible Place to Start

If all of this feels like a lot to hold in your head, reduce it to two decisions. Sow in late March. Plant out at the end of May. Those two dates will serve you well almost anywhere in the UK, and everything else on this page is refinement around them.

Then be later than feels right. Every gardener I know, myself very much included, has lost plants to impatience and none of us has ever lost one to waiting an extra fortnight. The plants catch up faster than you think, and a tomato that goes into warm soil and settled weather will overtake one that was rushed and checked. Grow two or three plants properly rather than eight badly, and you will get more tomatoes with less worry.