What to Plant in a Raised Garden Bed – UK Seasonal Guide

Raised Garden Beds

At a glance

Mar–AprStart sowing indoors
MayMain outdoor planting
Sep–OctAutumn planting window
Year roundSomething always growing

One of the biggest advantages of a raised bed over a traditional garden border is that you can grow something in it almost every month of the year. With a bit of planning, the same 1.2m × 2.4m bed that’s producing lettuces in April can be growing tomatoes in July and overwintering garlic by October. The key is knowing what to plant when – and that depends very much on where you are in the UK.

This guide is written for the UK climate specifically, not the sunnier American or Australian growing guides you’ll often find when you search for planting advice. The timings here account for our cooler springs, wetter summers and milder winters than most growing guides assume.

“A well-planned raised bed has something to harvest every single month of the year. Most people only use theirs for six.”

Spring planting – March to May

Spring is the most exciting time in the raised bed calendar. The soil warms faster than open ground, giving you a genuine head start on the growing season.

CropSow/plantSpacingHarvestNotes
Broad beansDirect sow March20cmJune–JulyHardy, can go in early
Lettuce & saladDirect sow Mar–Apr15cm6 weeksSow every 3 weeks for continuous harvest
RadishesDirect sow March+5cm4 weeksFastest crop in the garden
SpinachDirect sow March+10cm6–8 weeksBolt-resistant varieties for spring
Spring onionsDirect sow March+1cm (thin to 5cm)8 weeksSow thickly and thin
PeasDirect sow Mar–Apr8cmJun–JulProvide support – even dwarf varieties benefit
Potatoes (early)Plant Apr (after frosts)30cmJun–JulChit first for 3–4 weeks
Onion setsPlant March–April10cmJuly–AugEasier than seed for beginners
GarlicPlant March (or Oct)15cmJulyAutumn planting gives bigger bulbs
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The last frost date matters: In the UK, average last frost dates vary from late March in the south of England to mid-May in Scotland and northern England. Check your local average – planting frost-sensitive crops like courgettes and tomatoes outdoors before this date is risky. Always have fleece ready in April and May regardless of how warm it feels.

Summer planting – June to August

By June your raised bed should be in full production. This is also the time to plan for succession – what goes in as early crops come out.

CropPlant outSpacingHarvestNotes
TomatoesPlant out May–June45–60cmJul–OctBush/determinate vars best for beds
CourgettesPlant out May–June90cmJul–SepOne plant per square metre minimum
French beansDirect sow May–June15cmJul–SepDwarf varieties for beds
SweetcornPlant out June35cm (block plant)Aug–SepPlant in blocks for wind pollination
CucumbersPlant out June45cmJul–SepTrain up a trellis to save space
BeetrootDirect sow May–Jul10cmJul–OctSow every 4 weeks for succession
CarrotsDirect sow Apr–JunThin to 8cmJul–OctDeep, stone-free soil essential
KalePlant out June–July45cmSep onwardsPick outer leaves for months
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Watch for blight in July and August. UK summers — particularly in the north and west – create ideal blight conditions for tomatoes and potatoes. Choose blight-resistant tomato varieties like Crimson Crush or Koralik if your garden tends to be wet. Remove any yellowing leaves immediately and never water overhead.

Autumn planting – September to October

Autumn is the most underused season in UK raised beds. While most gardeners are clearing up, you can be planting crops that will overwinter and produce harvests from February onwards – a genuinely hungry gap filler.

CropPlant/sowSpacingHarvestNotes
GarlicPlant Oct–Nov15cmJune–JulyBest autumn crop — larger bulbs than spring planting
Overwintering onion setsPlant Sep–Oct10cmMay–JuneSpecific overwintering varieties only
Winter salad leavesSow Sep10cmOct–FebLamb’s lettuce, winter purslane, mizuna
Broad beans (autumn)Sow Oct–Nov20cmMay–JuneEarlier harvest than spring-sown
Spring cabbagesPlant Sep–Oct30cmMar–MayCover with fleece in hard frosts

Winter growing – what’s possible

A raised bed doesn’t have to sit empty from November to March. A simple polytunnel cloche or cold frame over the bed extends your growing season significantly:

  • Lamb’s lettuce (mâche) – genuinely frost-hardy, will grow all winter even uncovered in mild areas
  • Winter purslane – unusual but productive, tolerates temperatures down to -5°C
  • Mizuna and mibuna – fast-growing Asian greens that survive light frosts under a cloche
  • Kale – the hardiest brassica, improves in flavour after frost, harvest outer leaves all winter
  • Leeks – planted in summer, stand through winter and harvest as needed

Spacing and intensive planting

The key advantage of raised beds is that you never walk on the soil, so it never compacts. This means you can plant much more intensively than traditional row-based growing. Instead of rows with walking paths between them, plant in a grid pattern with just enough space between plants for air circulation.

A useful rule of thumb: plant at half the spacing recommended on the seed packet for row growing, but ensure every plant has at least 15cm of air space in every direction. This typically increases yield by 30–50% compared to conventional spacing.

Crop rotation basics

With a single raised bed, strict four-bed rotation isn’t possible – but some basic rotation still matters. The key rules:

  • Never grow the same brassica family in the same bed two years running — clubroot builds up in soil and is virtually impossible to eradicate
  • Move tomatoes and potatoes each year – both are in the Solanaceae family and share diseases including blight
  • Legumes (peas, beans) fix nitrogen – follow them with hungry crops like brassicas or sweetcorn that benefit from the nitrogen boost
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A raised bed that’s properly planned and succession planted will produce far more food than most people expect from the same amount of space. The key is never leaving soil bare – as one crop comes out, the next goes straight in. For more on getting the most from your raised bed, read our guide on the perfect raised bed soil mix to make sure your growing medium is working as hard as your planting plan.

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About the writer

James

Greater Manchester, England

Forty-something allotment holder, hobby gardener, and occasional sufferer of clay soil. I write about what actually works in a real British garden - not what looks good on a mood board.