What to Plant in March in the UK

March is when UK gardens go from planning to doing. The soil starts to warm up and frosts ease in sheltered spots. The RHS March jobs list is a handy companion for jobs beyond sowing.

This guide covers the main veg, flowers, herbs and fruit to sow or plant in March. It’s split into indoor sowings, outdoor sowings and planting out, with notes for gardens in the north and south. For the whole year, see our seed sowing calendar, or browse more growing guides.

Indoor sowings for March

March indoor sowing is all about tender crops that need warmth to sprout and a head start before the last frost. They stay inside until late May or early June.

Tomatoes, peppers, and chillies

Sow tomatoes in early March if you have a heated propagator, set to around 18-21C. They usually come up in a week or two. Peppers and chillies like the same warmth but are slower. Our guide to growing tomatoes takes you through the rest.

Sow two seeds per 7cm pot, 1cm deep, and pull out the weaker one once they’re up. Keep them on a bright windowsill or under a grow light. They need 6-8 weeks indoors before going outside.

Aubergines and cucumbers

Aubergines need warmth all season, so sow them in early March somewhere really warm, around 21-25C. They’re slower than tomatoes and need every week they can get. See our guide to growing aubergines. Cucumbers can wait until late March or early April.

Courgettes and squash

Wait until April to sow courgettes and squash indoors. They grow so fast that a March sowing outgrows its pot long before it’s safe to plant out. About four weeks indoors is plenty. When you do sow, use 9cm pots and push the seeds in on their edge, 2cm deep. Our courgette guide has the details.

Sweetcorn

Sweetcorn is better sown indoors in April. Earlier sowings sit in their pots too long and sulk when planted out. Use deep modules or root trainers, as it hates having its roots disturbed. Plant it out in a block, not a row, after the last frost, so the wind can pollinate it. More in our guide to growing sweetcorn.

Gardener’s tip: Label everything you sow with the variety and date. March is hectic, and by May unlabelled trays become a guessing game.

Labelled seed trays on a greenhouse bench. Tender crops started now get a head start of six weeks or more.

Outdoor vegetable sowings

Hardy veg can go outside once the soil is about 7C and not soggy. A soil thermometer pushed 10cm into the ground tells you. Mild southern and coastal gardens warm up first, and the Midlands and north are often a few weeks behind. Cover the soil with a cloche or fleece for a week or two to warm it up faster.

Broad beans

Broad beans are one of the easiest March sowings. Sow 5cm deep and 20cm apart in double rows. Aquadulce Claudia and The Sutton both do well. You’ll be picking from late June. Our broad bean guide has more.

Broad beans add nitrogen to the soil through little nodules on their roots. When you clear them after picking, cut the stems and leave the roots in the ground. Cabbages planted there later will thank you.

Peas

Sow peas in March for early summer picking. Early varieties like Kelvedon Wonder and Meteor suit a March start. Sow 5cm deep and 5cm apart in a flat-bottomed trench. Put pea sticks or netting in straight away, as they climb fast. See our guide to growing peas.

Like broad beans, peas feed the soil a little. Follow them with hungry crops like tomatoes and courgettes. For crop rotation and planning, see our guide on how to start a vegetable garden.

Root vegetables

March is a great month for root veg:

• Parsnips: sow straight into the ground, 2cm deep, in rows 30cm apart. Use fresh seed every year, as old seed doesn’t come up well. They’re slow to sprout, so be patient. In cold, wet soil, waiting until April often works better.
• Carrots: in mild areas with light soil, sow from mid-March under cloches or fleece. Sow thinly in rows 15cm apart. Fine mesh or fleece also keeps carrot fly off.
• Beetroot: sow from mid-March, 2-3cm deep, in rows 20cm apart. Each “seed” is actually a cluster that gives 2-3 seedlings. Thin to one when they’re 5cm tall.
• Turnips: sow straight outside from mid-March, 2cm deep, 15cm apart.

Leafy greens

Sow spinach, lettuce, rocket and spring onions straight into beds from mid-March. In colder gardens, use cloches. Sow short rows every 2-3 weeks to keep the salad coming all summer.

Can you plant onion sets in March?

Yes, March is a good time to plant onion sets, plus shallots and garlic. Sets planted in spring are usually ready from July to September. Pick a sunny spot with well-drained soil, and dig in some compost first.

Push each set in so the tip just shows, about 2cm deep. Space them 10-15cm apart in rows 20-30cm apart. More space means bigger bulbs. Birds love pulling new sets out, so check them for the first few weeks and push any back in. On heavy, wet soil, wait until you can work the ground rather than planting into mud.

Warning: Don’t sow French beans, runner beans or courgettes outdoors in March. They can’t take frost. Wait until late May to sow these outside.

Making seed drills in a March veg plot. A string line keeps rows straight, and a rake handle gives an even depth.

Potatoes

First early potatoes go in around late March. Mild southern gardens can start a bit earlier, and colder northern ones later. The soil needs to be workable, not soggy or frozen. Second earlies follow in early to mid-April. Our guide to growing potatoes covers the whole season.

Chitting

Chitting just means letting seed potatoes sprout before planting. Start 4-6 weeks ahead. Stand them in egg boxes with the end that has the most eyes pointing up. Keep them in a bright, frost-free room, not a dark cupboard. You want short, sturdy shoots. Shoots grown in the dark are pale, spindly and snap off.

Chit seed potatoes in good light so the shoots come out short, dark and sturdy. Pale, spindly shoots from a dark cupboard snap off at planting.

Planting

Dig a trench 15cm deep. Space first earlies 30cm apart in rows 60cm apart. Set the potatoes in with the shoots pointing up, cover with soil and water well.

First early varieties for March planting:

Gardener’s tip: If frost is forecast once shoots appear, pull soil over them. This is called earthing up. It protects the new growth and keeps the potatoes in the dark, as green potatoes aren’t safe to eat.

Flowers to sow and plant in March

March is a great month for flower sowing. Hardy annuals go straight outdoors. Half-hardy annuals start indoors.

Hardy annuals for direct sowing

These cope with frost and grow happily from March sowings outside:

• Sweet peas: sow 2cm deep where they’ll flower, or in root trainers to plant out later. Pinch out the tip once they have a few pairs of leaves to make them bushy. Pick them often and they’ll flower all summer. A must for any cottage garden planting plan.
• Calendula: scatter the seed on prepared soil and rake it in lightly. It flowers from June, seeds itself about, and is one of the best bee-friendly garden plants.
• Cornflowers: sow where you want them to flower and thin to 20cm apart. Blue, pink and white ones are available.
• Nigella (love-in-a-mist): scatter on open ground. It doesn’t like being moved. Thin to 15cm apart.
• Poppies: Californian and Shirley poppies grow well from March sowings. Mix the tiny seed with sand to spread it evenly.

Half-hardy annuals for indoor sowing

Start these on a warm windowsill or in a greenhouse:

• Cosmos: sow at 15-18C. One of the easiest cut flowers for UK gardens. Pinch out the tip of young plants for a bushier shape.
• Zinnias: sow at 18-21C. They hate root disturbance, so sow in single pots.
• Dahlias from seed: sow at 18C and they’ll flower in their first year. They also make tubers you can lift and keep. See our guide to growing dahlias.

Which summer bulbs can you plant in March?

March is early for most summer bulbs, but some can start under cover. Pot up dahlia tubers in a greenhouse or on a bright windowsill to wake them up. Lilies can go into pots or borders in spring, as long as the soil isn’t waterlogged.

Gladioli need a bit of patience. The big summer ones go in from mid-April through May, while the smaller early-flowering types can go in from late March. Plant the corms 10-15cm deep, in batches two weeks apart to spread the flowers. Keep tender dahlias inside until the frosts are over.

Planting out

March is also the time to plant bare-root roses, deciduous shrubs and perennials. Get them in before they start into leaf. Water well and mulch with garden compost to keep the soil moist. Our guide to growing roses has more, and see how to prune roses for getting the best from them.

Sweet peas climbing a willow obelisk. Sow them in March for flowers from June to September.

Herbs to start in March

Most kitchen herbs can be started in March, indoors or out depending on how hardy they are.

Sow indoors

• Basil: needs warmth, around 18-20C. Sow thinly on top of damp compost and cover with a fine layer of vermiculite. The usual mistakes are sowing too deep and using cold compost.
• Coriander: sow in deep pots, as it has a long root. Keep it cool. Heat makes coriander run to seed in no time.

Sow outdoors

• Parsley: sow outside in mild areas, 1cm deep, or in modules indoors. It’s slow, often taking several weeks to come up.
• Chives: sow, or split an existing clump. One of the first herbs to wake up in spring.
• Dill: wait until April and sow it where it’s going to grow, as it hates being moved.

Plant out

March is a good time to plant pot-grown rosemary, thyme, sage and oregano. These Mediterranean herbs like well-drained soil and full sun. Add grit to heavy clay before planting, or see how to improve clay soil for a longer-term fix.

Fruit to plant in March

Strawberries

Plant cold-stored strawberry runners in March. They settle in quickly in spring. Space them 35cm apart in rows 75cm apart. Elsanta and Cambridge Favourite are reliable. For more, see our guide on growing strawberries.

Raspberry canes

Plant raspberry canes in March, either bare-root before they come into leaf or pot-grown. Summer types like Glen Ample fruit on last year’s canes. Autumn types like Autumn Bliss fruit on this year’s growth, which makes pruning simpler.

Fruit trees

March is your last chance to plant bare-root fruit trees. Pot-grown trees can go in later, but bare-root ones need to root in before the leaves open. Water well after planting and stake them firmly.

March is the last chance for bare-root fruit trees, as they need to root in before the leaves open. Water well and stake firmly.

March planting calendar

A tidy potting bench ready for the March rush. Group your seeds into indoor, outdoor and plant-out piles.

Common mistakes with March sowing

Sowing too deep

Small seeds only need a light covering. Sow lettuce and basil on top of damp compost and cover with a thin layer of vermiculite, not a thick blanket of soil. Lettuce actually comes up better with a bit of light.

Sowing tender crops outdoors too early

French beans, runner beans, courgettes and sweetcorn can’t survive frost. Late frosts in April and May often catch out crops put out too early, so keep them inside until it’s safe. Check outdoor seedlings for slugs on damp evenings, as March sowings are easy pickings.

When is the last frost in the UK?

There’s no single date, but the last frost usually comes earlier in the south than the north. The Met Office explains that southern and coastal areas often see their last air frost before the end of April. In the north and on high ground, frost often carries on well into May, and in a few places into June.

Ground frost is the one to watch. It can freeze the soil surface even when the air stays just above 0C, and it’s common in May. That’s why tomatoes, courgettes and dahlias usually stay under cover until late May in much of the UK. Keep an eye on the local forecast and have fleece ready for cold, clear nights.

Ignoring soil temperature

The packet says “sow March”, but your soil might not be ready. Cold, wet soil rots seeds before they sprout. A cheap soil thermometer saves a lot of wasted seed. Most hardy crops want the soil at about 7C.

Overcrowding seed trays

Sowing too thickly gives you leggy, weak seedlings fighting for light. Sow thinly and prick out early. A few strong seedlings will do better than a crowded tray of spindly ones.

Forgetting to harden off

Plants moved straight from a warm windowsill to the garden get a nasty shock. Hardening off means getting them used to outdoor life bit by bit. Do it over 10-14 days, leaving them out a little longer each day.

Checking the soil before sowing. Most crops want it at 7C or more.

Regional differences across the UK

Timings can shift by several weeks between the mild south-west and the colder north. March in Cornwall is very different from March in Aberdeenshire.

Southern England and sheltered coastal areas

The mildest March weather. The soil warms first here, so hardy crops can go outside from early March. First early potatoes can go in from mid to late March. Frost is still possible into April.

Midlands and central England

The soil warms more slowly. Outdoor sowings usually do best from mid-March, under fleece or cloches at first. Potatoes go in from late March.

Northern England and Scotland

March is colder and wetter. Concentrate on sowing in a greenhouse or on a windowsill, and hold outdoor sowings until late March or early April. First earlies usually go in from late March to early April, so check our guide on when to plant potatoes. Fleece is a must for early crops.

Exposed and upland gardens

High up, March is still winter, so stick to indoor sowing. Outdoor planting starts in April, and our April planting guide covers what’s next. Raised beds warm up faster than ground-level soil, so raised bed gardening can give you a longer season.

For next month, see the guide to what to plant in April.

Frequently asked questions

What vegetables can I plant in March UK?

Lots, it’s a busy month. Sow tomatoes, peppers and aubergines indoors. Outdoors, sow broad beans, peas and parsnips once the soil has warmed to about 7C, with carrots and beetroot under cloches in mild areas. Plant onion and shallot sets, and first early potatoes around late March.

Is it too early to plant seeds outside in March?

No, plenty of seeds can go outside in March. Hardy crops like broad beans, peas, parsnips and spinach cope with the cool weather. If the soil feels cold and sticky, wait a week or two, or warm it under a cloche first.

When should I start seeds indoors in March?

From early March for tender crops. Tomatoes, peppers, chillies and aubergines need a warm spot, like a heated propagator or a warm windowsill. They need 6-8 weeks indoors before planting out after the last frost.

Can I plant potatoes in March?

Yes, first earlies go in around late March. Second earlies follow in early to mid-April. Mild areas can start a little earlier and cold northern gardens a little later. Chit your seed potatoes for 4-6 weeks first.

What flowers can I sow in March?

Sweet peas, calendula, cornflowers and nigella can go straight outdoors. Start dahlias, cosmos and zinnias indoors on a warm windowsill. Hardy annuals cope with March frosts, but half-hardy ones need to stay inside until the frosts are over.

Should I use a greenhouse or sow outside in March?

Use both if you can. A greenhouse lets you start tender crops like tomatoes and peppers. If you only have outdoor space, stick to peas, broad beans, root veg and hardy annuals, which all do well from March sowings.