The other thing that makes May useful is variety. You can sow fast crops like salad leaves and radishes that will be ready in weeks. You can sow slower crops like carrots and beetroot that will fill the veg patch through summer and autumn. You can start leeks and brassicas that won’t be harvested until winter. And you can get flowers in the ground that will be blooming by July. All in the same month, in the same beds, without a greenhouse in sight.

This guide covers what to sow in May in the UK in detail, crop by crop, so you know exactly what goes in the ground now, what to start indoors, and what to avoid rushing before conditions are ready. For a broader look at everything you can do in the garden this month beyond just sowing, May Gardening Jobs in the UK covers the full picture.

Getting the Soil Ready Before You Sow

Before anything goes in the ground it’s worth spending ten minutes on the soil. You don’t need to dig everything over or add bags of compost before every sowing, but a bit of basic preparation makes a real difference to how well seeds germinate.

The main thing you want for direct sowing is a fine, crumbly surface that seeds can make good contact with. If your soil is lumpy, compacted, or has a crust from recent rain, break it up with a rake and work it into a reasonable tilth before sowing. Seeds that sit in air pockets or can’t contact moist soil consistently will germinate patchily or not at all.

If a bed has had nothing added to it for a while, working in some compost before sowing is worthwhile. It doesn’t need to be a deep dig, just mixing some into the top layer where the seeds will sit. How to Improve Garden Soil in the UK covers the practical side of this, and Best Compost for Vegetables in the UK covers what’s actually worth buying.

One more thing: check moisture levels before sowing. The soil should be damp but not wet. If it’s dry, water it a day before sowing rather than after, so the moisture is evenly distributed through the surface layer when the seeds go in.

Vegetables to Sow Directly Outside in May

Direct sowing means putting seeds straight into the ground outdoors rather than starting them in pots or trays. May is the best month of the year for this because soil temperatures are high enough for seeds to germinate quickly without rotting, and the weather is generally warm enough to keep growth moving.

Carrots

Carrots are one of the most rewarding things to sow in May. Germination is far more reliable now than in March or April when the soil is still cold and wet, and you get much less of the patchy, uneven emergence that frustrates early season sowing.

Sow thinly into drills about 1cm deep and 30cm apart. Carrots don’t like transplanting so they need to go straight into their final position. Thin to about 5-8cm apart once they’re established, or you’ll get lots of small, twisted roots fighting for space.

One of the best things you can do with carrots is sow in succession, a short row every two to three weeks through May and into June, rather than sowing a large amount all at once. You end up with harvests spread over months rather than everything coming ready at the same time. When to Plant Carrots in the UK covers the timing in full.

Beetroot

Beetroot is probably the most beginner-friendly crop you can sow in May. It germinates quickly in warm soil, grows without drama, tolerates a certain amount of neglect, and produces harvests you can actually use in the kitchen. If you’re not sure where to start in May, beetroot is always a safe choice.

Sow about 2cm deep in rows 30cm apart. Each beetroot “seed” is actually a cluster of seeds, so you’ll almost always get more than one seedling per planting position. Thin down to one plant per position once they’re a few centimetres tall. Like carrots, succession sowing every two to three weeks gives you a much more manageable harvest. When to Plant Beetroot in the UK has the full timing guide.

Peas

Early May is still within the pea sowing window, but it is the tail end of it. Peas prefer cooler growing conditions and once summer heat arrives they struggle, so anything sown after mid-May is a bit of a gamble depending on your location. Get them in during the first two weeks of May for the best results.

Sow about 5cm deep in double rows, with seeds roughly 8cm apart within the row. Peas need support as they grow, so put canes or pea sticks in at sowing time rather than waiting until they’re already flopping over. When to Plant Peas in the UK explains the window clearly and what to expect from later sowings.

French Beans

French beans are a warm-soil crop and mid-May is the earliest you should sow them outdoors. Any earlier and the seeds tend to sit in the ground without germinating, or they rot before they get the chance. The difference between sowing French beans in late April and mid-May is often the difference between success and a failed sowing.

Sow about 5cm deep in rows 45cm apart, with seeds roughly 15cm apart in the row. They grow quickly once conditions are right and you can expect to be harvesting within 10-12 weeks of sowing. Climbing varieties need support; dwarf varieties are more compact and don’t need staking. When to Plant French Beans in the UK covers the timing in detail.

Runner Beans

Runner beans follow the same logic as French beans, mid to late May for outdoor sowing, once the soil is warm and overnight temperatures have settled above 10°C. They’re one of the most productive crops in a UK vegetable garden, and a couple of plants will produce more beans than most families can keep up with through summer.

Sow 5cm deep, about 15-20cm apart along a row of canes or a wigwam structure. Put the supports in before or at the same time as sowing, not after, so you’re not disturbing roots later. Water well after sowing and keep an eye on soil moisture in the first few weeks. When to Plant Runner Beans in the UK has the full timing guide.

Salad Leaves and Lettuce

Salad leaves, cut-and-come-again mixes, spinach, and lettuce are among the fastest and most satisfying crops to sow in May. Germination is quick, harvests can start within four to six weeks of sowing, and you can cut the leaves repeatedly rather than pulling the whole plant.

Scatter seeds thinly over a prepared bed or sow in shallow drills about 1cm deep. Thin once seedlings are a few centimetres tall. Like carrots and beetroot, succession sowing a small amount every couple of weeks makes much more sense than sowing a large amount at once and ending up with more salad than you can eat before it bolts.

Spinach is worth growing separately from salad mixes as it has slightly different needs, it prefers not to dry out and can bolt quickly in hot, dry conditions. When to Plant Spinach in the UK covers the timing and how to manage it through summer. For lettuce specifically, When to Plant Lettuce in the UK explains the best varieties for May sowings.

Spring Onions and Radishes

Both of these are worth sowing if you want something genuinely quick. Radishes can be ready in as little as four weeks from sowing in May, making them one of the fastest crops in the kitchen garden. Spring onions take a little longer, around eight weeks, but they’re dependable and can be used fresh from the ground.

Sow radishes thinly in shallow drills and thin to about 3cm apart once germinated. Don’t leave them in the ground too long once they’re ready, they turn woody and unpleasant within days of reaching harvest size. Sow a small amount every ten days for a continuous supply rather than a single large sowing.

Courgettes

Courgettes can be sown directly outside from late May in sheltered, mild gardens. Most people start them indoors in April for planting out in May, but if you haven’t done that, a direct outdoor sowing in the last week of May is perfectly viable in most UK gardens. They germinate fast once soil temperatures are consistently above 15°C.

Sow two seeds per position, about 2cm deep, and remove the weaker of the two seedlings once they’re established. Give each plant plenty of room, they spread considerably. How to Grow Courgettes in the UK covers the full process from sowing to harvest.

Sweetcorn

Late May is the right time to sow sweetcorn directly outside in warmer parts of the UK. In the north or on exposed sites it’s safer to start indoors in late April or early May and plant out in June. Sweetcorn is wind-pollinated and needs to be grown in a block, not a single row, so each plant pollinates its neighbours.

Sow 2.5cm deep in a grid pattern with about 45cm between plants. They need a warm, sheltered spot and consistent moisture to crop well. Don’t bother growing sweetcorn in a cold or shaded garden, it just doesn’t produce enough in poor conditions to be worthwhile. How to Grow Sweetcorn in the UK covers the full process from seed to harvest.

Potatoes

Maincrop potatoes can still go in during early May in most UK gardens, particularly in northern areas where later planting is normal. If you’re in the south and haven’t planted yet, early May is getting late for maincrops but still worth doing. First and second earlies planted now will produce a later harvest than usual but will still crop. When to Plant Potatoes in the UK covers the full timeline by variety and region.

Flower Seeds to Sow in May in the UK

May is an excellent month for sowing flowers directly outside. Hardy annuals in particular do well when sown now, they establish quickly in warm soil and most will be flowering by July or August. For the full guide including bedding plants and summer bulbs, What Flowers to Plant in May in the UK goes much deeper into flowers specifically.

Nasturtiums

Nasturtiums are almost impossible to fail with in May. Sow them where you want them to flower, cover lightly with soil, and water in. They germinate within a week in warm conditions and produce flowers from June onwards. They work well in vegetable gardens too, attracting aphids away from other crops and bringing in beneficial insects.

Cornflowers

Cornflowers sown directly in May will flower from July and keep going until the first frosts. Sow thinly in drills, thin to about 15cm apart, and deadhead regularly to keep them producing. They’re fully hardy and ask for very little once established.

Calendula

Calendula (pot marigold) is another May sowing that gives a lot back for very little effort. Sow directly outside, thin to 30cm apart, and deadhead regularly. Like nasturtiums, they work well alongside vegetables and are edible, the petals can be used in salads.

Sunflowers

Sunflowers can be sown directly outside in May once frost risk has passed. Sow 2.5cm deep in their final position as they don’t transplant well. Give them full sun and shelter from wind if possible. They’re one of the most satisfying plants to grow from seed and children in particular love watching them develop.

Borage, Phacelia, and Annual Poppies

All three of these can be scattered directly where you want them to flower in May. They germinate readily in warm soil and are excellent for attracting pollinators. Borage in particular is worth growing near vegetable beds as it draws bumblebees and other beneficial insects.

What to Sow Indoors or Under Cover in May

Not everything sown in May goes outside immediately. A few crops benefit from being started indoors or under cover in May for planting out later in the season.

Leeks

Leeks are a long-season crop that need starting in May to give them enough time to develop before autumn. Sow thinly in a seed tray or small pot indoors and they’ll be ready to plant out into their final positions in June or July. They’re one of the most dependable winter vegetables and well worth the growing time. When to Plant Leeks in the UK covers the full sowing and planting schedule.

Kale and Purple Sprouting Broccoli

Kale and purple sprouting broccoli both need to be started in May if you want harvests through winter and early spring. Sow in individual pots or a seed tray under cover and plant out in June once they’ve developed a few true leaves. These are tough, reliable crops that occupy space in the garden for a long time, so it’s worth getting the timing and spacing right before committing. When to Plant Brassicas in the UK covers the full schedule for all brassica types.

Brussels Sprouts

If you want Brussels sprouts for Christmas, May is genuinely your last chance to sow them. They need a very long growing season, around six months from sowing to harvest, so seeds going in now will produce sprouts from November onwards. Start indoors or under cover and plant out into a firm seedbed in June.

Basil

Basil needs warmth to germinate well and is best sown indoors in May rather than outside. Full timing guidance is in When to Plant Basil in the UK, and How to Grow Basil from Seed in the UK covers the full process from sowing through to harvest. It’s one of the most temperature-sensitive herbs and even a mild cold snap outdoors can check its growth badly. For the wider picture across all UK herbs, see growing herbs at home. Sow in small pots on a warm windowsill, keep it there until June, and only move it outside once you’re sure overnight temperatures have settled.

Succession Sowing in May

One of the most useful habits to get into with May sowing is thinking in terms of succession rather than single large sowings. The idea is simple: instead of sowing a whole row of carrots or a large patch of salad in one go, you sow a small amount and then sow another small amount two to three weeks later, and so on through the growing season.

The result is that you get a steady supply of crops coming ready at different times rather than everything being ready at once. This is particularly useful for fast-growing crops like radishes, salad leaves, spring onions, and lettuce, where a single large sowing can produce more than you can use before it goes past its best.

For slower crops like carrots and beetroot, succession sowing spreads the harvest across a longer period and also means that if one sowing is hit by pests or bad weather, you haven’t lost everything.

Common Sowing Mistakes in May

A few mistakes come up repeatedly in May that are worth knowing about before you start.

Sowing too deep. Most vegetable seeds are smaller than you think and don’t need to go in very deep. The general rule is to sow at a depth of roughly twice the diameter of the seed. Sowing too deep means seeds have to push through too much soil before they reach light, and many don’t make it. If in doubt, sow shallower rather than deeper.

Sowing too thickly. It’s tempting to sow generously to make sure you get enough plants, but overcrowded seedlings are harder to thin, compete badly with each other from the start, and are more vulnerable to fungal problems caused by poor air circulation. Sow thinly and thin properly once they’re established.

Not watering after sowing. Seeds need consistent moisture to germinate. A dry spell right after sowing can stop germination altogether, or worse, start it and then kill the seedlings before they reach the surface. Water the bed gently after sowing and keep the soil evenly moist until germination is underway. How Often to Water Plants in the UK covers the detail on watering through the growing season.

Forgetting to thin. Thinning is the job most beginners skip or put off, and it shows in the final harvest. Crowded seedlings produce small, misshapen crops and are more prone to disease. Thin properly to the recommended spacing and resist the urge to leave them all in hoping they’ll find their own space. They won’t. When to Thin Vegetable Seedlings in the UK explains how to do it without second-guessing yourself.

Sowing warm-season crops too early in May. French beans, runner beans, and courgettes all need warm soil to germinate properly. Sowing them in early May when soil hasn’t fully warmed often results in failed germination or rotting seeds. Wait until mid to late May for these crops and the success rate improves significantly.

Protecting May Sowings from Pests

Two pests are worth thinking about whenever you sow in May.

Slugs are at their worst in warm, damp conditions and young seedlings emerging in May are exactly what they’re looking for. A row of carrot seedlings can disappear overnight if slugs are active in your garden. Check after dark to get a sense of numbers and deal with them before they establish. How to Get Rid of Slugs in the Garden covers the methods that actually make a difference.

Birds can also be a problem with freshly sown beds, particularly for peas and beans where they’ll pull seeds straight out of the ground. A simple covering of netting or a few twiggy sticks pushed into the soil around the sowing area is usually enough to deter them while seeds germinate and establish.

FAQs

A Sensible Place to Start

May gives you more sowing options than any other month in the UK gardening year. Hardy crops like carrots, beetroot, and salad leaves can go straight in the ground right now. Slightly more demanding crops like French beans and runner beans can follow from mid to late May once the soil has properly warmed. Flowers like nasturtiums and cornflowers can go in whenever you’re ready. And slower crops like leeks and brassicas are worth getting started indoors this month for harvests later in the year.

The thing to avoid is trying to do everything at once in the first week of May. Stagger your sowings, do a little at a time, and build in succession sowings for the faster crops. It takes about the same amount of effort as doing it all in one go, and the results over the next four to five months are considerably better.

If you’re not sure where to begin, start with three crops: beetroot, salad leaves, and nasturtiums. All three are low risk, quick to germinate, and immediately rewarding. Once those are in the ground and growing the rest of the season tends to take shape naturally. For everything else worth doing in the garden beyond sowing this month, May Gardening Jobs in the UK covers the full picture. And for the full year of sowing and harvest dates on one page, bookmark the our month-by-month sowing guide.

If you haven’t planned out your garden yet, our free UK Vegetable Garden Planner is a quick way to work out exactly what to plant and where based on your space and location.

This is a practical rundown of the gardening jobs for May in the UK not an overwhelming masterclass, just the things that genuinely make a difference this month. Work through them at your own pace and the rest of the season tends to look after itself.

Get Your Tender Plants Outside

If you’ve been nursing tomatoes, courgettes, cucumbers, or squash on a windowsill since March, May is when they finally get to go outside. The key is not to rush it. Early May still carries a frost risk in many parts of the UK, and plants that go from a warm house straight into an exposed bed often just sit there sulking for weeks.

The process you want is hardening off taking plants outside during the day and bringing them back in at night over a week or two before leaving them out permanently. It sounds fiddly but it makes a real difference. Plants that are properly hardened off establish quickly. Plants that skip that step often don’t.

From late May, once overnight temperatures are reliably above 10°C, most tender crops can go out and stay out. If you’re not sure what can go out when, What to Plant in May in the UK has the full breakdown.

Sow Directly Outside

May is one of the best months of the year for sowing directly into the ground. The soil is warm, days are long, and seeds that struggled to germinate in the cold of March will shoot up quickly now.

The crops worth getting in now are carrots, beetroot, peas (early May only the window starts to close as it warms up), French beans, runner beans, salad leaves, spinach, and spring onions. If you’re doing maincrop potatoes in the north, early May is still within the planting window too.

It’s also a great month to get flowers in the ground. Hardy annuals like nasturtiums, cornflowers, and calendula can go straight into prepared soil right now. What Flowers to Plant in May in the UK covers what to sow, what to plant out, and which flowers work best alongside vegetables.

For the full sowing guide with depths, spacing, and succession sowing advice, What to Sow in May in the UK covers everything in detail, and what to sow in July in the UK covers the later summer sowings for autumn and winter crops.

One thing worth doing with carrots and salad leaves is sowing a short row every two to three weeks rather than one big sowing all at once. It staggers the harvest and means you’re not pulling everything at the same time and wondering what to do with it all. When to Plant Carrots in the UK covers the succession sowing timing clearly.

Start Leeks and Brassicas Indoors

Not everything is about getting things outside. May is the right time to start leeks indoors or in a seedbed for planting out later in summer they’re a slow crop and if you leave it too late the timeline doesn’t work. Same goes for brassicas like kale, purple sprouting broccoli, and Brussels sprouts, which all benefit from being started now under cover and planted out in June.

These crops will be in the ground for months, so it’s worth getting the timing right from the start. When to Plant Leeks in the UK and When to Plant Brassicas in the UK cover the sowing and planting schedules in full.

Thin Your Seedlings

If you sowed carrots, beetroot, lettuce, or other direct-sown crops in April, they’re probably coming up nicely now. And they’re probably too crowded. Thinning feels brutal you’re pulling out perfectly healthy seedlings but leaving them too close together almost always means worse results for everyone. They compete for water, light, and nutrients, and none of them win.

The general rule is to thin to the spacing recommended on the packet. Do it in stages if it helps thin once when they’re small, then again a week or two later when you can see clearly which ones are strongest. When to Thin Vegetable Seedlings in the UK explains how to do it without second-guessing yourself.

Start Feeding Hungry Plants

Once plants are in active growth which by May most of them are feeding starts to matter. Tomatoes, courgettes, cucumbers, and other hungry crops benefit from a regular liquid feed once they’re established and growing. Don’t bother feeding seedlings that have just gone in the ground; give them a week or two to settle first.

The thing most people get wrong with feeding is doing too much too soon, which pushes lots of leafy growth at the expense of fruit and roots. A balanced feed at the right stage works far better than lots of feed at the wrong one. getting feeding right is worth a read before you start reaching for the bottle every week.

Deal With Slugs Before They Get Out of Hand

Slugs are at their worst in May. Mild evenings, damp soil, and rows of tender young seedlings it’s basically a slug paradise. If you’ve ever wondered why your seedlings disappeared overnight between sowing them and expecting to see them come up, this is almost certainly why.

The good news is that a bit of action early in the season is worth far more than trying to deal with the problem once it’s out of hand. Check plants after dark if you want to see what you’re dealing with. Copper tape, wool pellets, and nematodes all work without harming anything else in the garden. How to Get Rid of Slugs in the Garden covers the methods that actually make a difference.

Keep an Eye on Frost

May is a brilliant month, but it has a sting in its tail. A cold, clear night in the first two weeks of the month can still bring a ground frost, and tender plants that went outside too early are the ones that suffer. A layer of fleece over vulnerable plants is all you need it doesn’t look glamorous but it works.

If you’re not sure when your last frost date typically falls in your area, UK Last Frost Dates by Postcode is genuinely useful. And if frost is forecast when you’ve already planted out, How to Protect Vegetables from Frost in the UK covers what to do quickly.

Sort Out Your Soil Before It’s Too Late

If there are still beds that haven’t had anything done to them, May is your last real chance to improve them before the growing season is properly underway. Adding compost and working it into the top layer of soil makes a real difference to how well crops establish especially in heavy clay or light sandy ground.

You don’t need to dig everything over. In fact, minimal digging is often better. The goal is just to give the top layer some structure and organic matter before plants go in. How to Improve Garden Soil in the UK is the practical guide for this, and Best Compost for Vegetables in the UK covers what’s actually worth buying.

Water Consistently But Not Obsessively

May can be surprisingly dry in the UK, and newly sown seeds and recently planted crops both need consistent moisture to establish properly. The most common watering mistake is doing it little and often a quick splash every day that only wets the surface rather than a thorough soak less frequently that actually reaches the roots.

Water in the morning if you can, keep it off the leaves where possible, and let the soil dry out slightly between waterings rather than keeping it permanently soggy. Overwatering causes just as many problems as underwatering. How Often to Water Plants in the UK has the detail on getting this right.

FAQs

A Sensible Place to Start

May can feel overwhelming because there’s so much going on. But most of it doesn’t need to happen on day one. Work through the list steadily get tender crops hardened off and outside, keep up with sowing, deal with slugs early, and make sure things are getting enough water. That covers the essentials.

The rest feeding, soil improvement, thinning can follow as you go. Gardening in May is supposed to be enjoyable, not a race. The garden doesn’t need everything done at once. It just needs you to show up regularly and pay attention. The same monthly approach continues in June gardening jobs and August gardening jobs in the UK.

If you’re looking for a broader picture of what the whole growing season looks like, What to Do in the Garden Each Month covers the full year in the same practical style. And if you have plants ready to go outside this month, How to Harden Off Plants in the UK is one of the most important reads of May.

There’s a lot you can plant in May — both sowing seeds directly outside and getting tender crops that have been growing indoors moved out into the garden. The catch is that May has two halves. Early May still carries a frost risk in many parts of the UK, particularly in the north, on higher ground, and in known frost pockets. Late May is a different story, and the window opens up considerably once that risk has passed.

This guide covers the vegetables, seeds, and flowers worth planting in May in the UK, along with what’s still better kept indoors for now. For the full year overview, When to Plant Vegetables in the UK and for everything else worth doing in the garden in May beyond planting May Gardening Jobs in the UK. If sweetcorn is on your list this season, When to Plant Sweetcorn in the UK covers exactly when to sow and when it can safely go outside, and How to Grow Sweetcorn in the UK covers the full growing process.

Vegetables to Sow Directly Outside in May

May is one of the best months of the year for direct sowing — putting seeds straight into prepared beds outdoors. The soil is warm enough for reliable germination, and anything you sow now has months of growing weather ahead of it.

Carrots are one of the best veg to sow in May. Germination is far more consistent now than in the cold, wet soil of early spring, and you’re much less likely to get patchy rows. A lot of gardeners sow a short row every couple of weeks through May and into June rather than doing it all at once — it spreads the harvest and avoids a glut. When to Plant Carrots in the UK has the full regional timing.

Beetroot is one of the most dependable May sowings there is. It germinates quickly in warm soil, grows without much fuss, and is genuinely forgiving if you’re still finding your feet. When to Plant Beetroot in the UK covers the detail if you want it.

Peas can still go in during early May, though the window starts to close as the season warms up. If you haven’t sown any yet, get them in now. When to Plant Peas in the UK explains what to expect from later sowings.

French beans and runner beans can be sown outdoors from mid-May, once the soil has warmed properly and overnight temperatures have settled. Any earlier and the seeds tend to just sit there — or rot. It’s one of those crops where a bit of patience in May pays off in June. When to Plant French Beans in the UK and When to Plant Runner Beans in the UK are both worth a quick read before you sow.

Lettuce, salad leaves, spinach, and spring onions are among the easiest things you can sow in May. They’re fast, low-maintenance, and you can be harvesting within a few weeks. If you’re new to growing, these are great confidence-builders.

Potatoes can still go in during early May, particularly maincrop varieties in cooler northern areas where planting earlier wasn’t possible. If you’re in the south, first earlies may already be in the ground — but it’s not too late. When to Plant Potatoes in the UK covers the full timeline by variety and region.

Tender Crops to Plant Out in May

If you’ve been growing tomatoes, courgettes, cucumbers, or squash indoors since March or April, May is when they start moving outside. But not all at once, and not before they’re ready.

The step that makes the biggest difference is hardening off — gradually getting plants used to outdoor conditions over a week or two before leaving them out permanently. Move them outside during the day and bring them back in at night to start with. Plants that skip this step often sit there doing nothing for weeks, even when the weather looks fine. It’s worth doing properly.

Tomatoes are usually ready to go outside from late May, once overnight temperatures are consistently above 10°C. In a greenhouse or polytunnel, you can do it earlier. Rushing tomatoes out in early May is one of the most common mistakes of the month — they look okay for a few days and then stop. When to Plant Tomatoes in the UK covers the timing in full.

Courgettes can go outside from mid to late May in milder, sheltered gardens — but late May or early June is more sensible in the north or in exposed spots. One cold night can set them back badly. How to Grow Courgettes in the UK covers everything from sowing to harvest.

Cucumbers go outside from late May, but only in genuinely warm and sheltered spots. They’re more sensitive to cold than courgettes and often do better kept under cover in the UK. When to Plant Cucumbers in the UK will help you decide whether outdoor or indoor growing suits your space better.

Growing in containers rather than open ground? The same rules apply — tender crops need warm nights before they go outside, whatever size pot they’re in. Can You Grow Vegetables in Pots in the UK? covers what works well in containers through the season.

Flowers to Plant in May in the UK

May is also a good month to get flowers in the ground, whether you’re growing them alongside vegetables, in borders, or in pots. For the full breakdown of what flowers to sow and plant out this month, What Flowers to Plant in May in the UK covers every option in detail. Hardy annuals like nasturtiums, cornflowers, and calendula can all be sown directly outside now and will flower through summer. They’re easy from seed and nasturtiums in particular are almost impossible to fail with.

If you want to plant out bedding that was started indoors — such as cosmos, marigolds, or antirrhinums — wait until the risk of frost has passed in your area before putting them outside permanently. The same hardening-off process that applies to tomatoes and courgettes applies here too.

Nasturtiums are worth a special mention if you’re growing vegetables too — they’re useful companion plants that attract aphids away from other crops and bring in beneficial insects.

Still Worth Starting Indoors in May

Not everything needs to go outside this month. Leeks are ideally started indoors or in a seedbed in May for planting out later in summer. They’re a long-season crop and starting them now keeps the whole timeline on track for an autumn and winter harvest. When to Plant Leeks in the UK covers the full schedule.

Brassicas for autumn and winter — kale, purple sprouting broccoli, and Brussels sprouts — can also be started under cover in May for planting out in June. They’ll be in the ground for months, so it’s worth reading When to Plant Brassicas in the UK to get the spacing and timing right from the start.

Watch for Frost and Slugs

Frost catches people out in May every year. A clear, still night in the first two weeks of the month can drop temperatures enough to damage tender plants that went out too soon. If you’re not sure when your last frost typically falls, UK Last Frost Dates by Postcode is worth checking. And if frost is forecast after you’ve already planted out, How to Protect Vegetables from Frost in the UK covers what you can do quickly.

Slugs are the other May problem. Mild, damp evenings after spring rain are perfect conditions for them, and young seedlings are most vulnerable in the first few weeks. If they’re a persistent issue in your garden, How to Get Rid of Slugs in the Garden covers the methods that actually work.

Once seedlings are up, don’t skip thinning them. Crowded seedlings compete badly for light, water, and nutrients and rarely produce good crops. When to Thin Vegetable Seedlings in the UK explains how to do it without pulling out the ones you want to keep.

FAQs

A Sensible Place to Start

May has more planting options than almost any other month in the UK. Hardy veg like carrots, beetroot, and salad leaves can go straight in the ground now. Tender crops like tomatoes and courgettes follow from mid to late May once conditions are right. And if you want flowers too, hardy annuals like nasturtiums can go in right alongside your vegetables.

The trap most people fall into is rushing. Getting things outside too early, sowing into soil that hasn’t warmed properly, or skipping the hardening-off step all slow things down rather than speed them up. A slightly later start in the right conditions nearly always beats an earlier one that struggles.

If you’re not sure where to begin, pick two or three things rather than trying to do everything at once. Beetroot, lettuce, and French beans are all solid May sowings — fast results, low risk, and a good foundation for the rest of the season.For a more detailed guide to sowing seeds specifically, What to Sow in May in the UK covers every crop with sowing depths, spacing, and timing. And if you have tender plants ready to go outside, How to Harden Off Plants in the UK explains the two-week process that stops them stalling when they go out.