Seasonal Planting Calendar for UK Gardens

Start With the Soil, Not the Seed

A planting calendar is only ever as good as the ground it is written on. Before you sow a single seed, it pays to think about what grew in that spot last year and what will grow there next. Rotating crops is the single most useful habit a kitchen gardener can build, and it costs nothing but a little forethought.

The traditional approach splits vegetables into four groups: legumes (peas and beans), brassicas (cabbage, kale, broccoli), roots (carrots, parsnips, beetroot) and potatoes, with alliums such as onions, garlic and leeks slipping in alongside the roots. Move each group on by one bed every year and you interrupt the life cycles of pests and diseases, while giving the soil a varied diet of nutrients and root structures. Legumes leave nitrogen behind, so follow them with hungry brassicas. Roots dislike freshly manured ground, so put them after the potatoes, which will have had their fill the year before.

Autumn: The Quiet Powerhouse

Autumn is the season most new growers underestimate. The soil is still warm from summer, the rain is reliable, and anything established now gets a head start on spring.

• Broad beans: sow hardy varieties such as Aquadulce Claudia from late October to November in a sheltered spot. They will germinate, sit tight through the cold and race away in March, often cropping before spring-sown beans.
• Garlic and overwintering onions: plant cloves and sets from October onwards into well-drained ground. A raised bed or a ridge helps prevent waterlogging.
• Green manures: where a bed is empty, sow field beans or grazing rye rather than leaving bare soil. They protect the structure from winter rain and can be dug in or cut down in spring.
• Mulch: spread a generous layer of compost or well-rotted manure over vacant beds and let the worms do the digging for you.

Autumn is also the moment to clear spent crops promptly. Leaving tired courgette plants and bolted lettuces in place is an open invitation to slugs and disease.

Winter: Plan, Protect and Prepare

Growth slows to a crawl, but the gardening year does not stop. Under cloches, cold frames or a polytunnel, you can keep cutting winter salads, land cress, spinach and hardy herbs. A little ventilation on mild days prevents mould from taking hold.

This is the season for the jobs that make spring easier: sharpening tools, ordering seeds, and sketching next year's rotation on paper. Chit first early potatoes on a light windowsill from late January. Sort your compost heap, turn it if you can, and top up any beds that have settled over the wet months. Check drainage too — winter waterlogging does more damage to dormant roots than frost ever will.

Spring: Under Cover and Full Steam Ahead

As light levels climb, the pace quickens. Tomatoes are the classic spring project: sow them under cover from late February to early March in a heated propagator or a warm windowsill, then pot them on as they grow. They need steady warmth, bright light and careful watering, so resist the urge to move them to a cold greenhouse until nights are reliably above 10°C, usually by late May.

• February to March: sow aubergines, peppers, chillies and early tomatoes indoors.
• March to April: direct sow parsnips, carrots, spinach and beetroot once the soil is workable.
• April: plant out hardened-off brassicas under nets to keep pigeons and cabbage white butterflies at bay.
• May onwards: sow French and runner beans, courgettes and sweetcorn once the danger of frost has passed.

Hardening off matters. Move seedlings outside for a few hours a day over a week before planting, or a single cold night will undo weeks of careful work.

Summer: Succession Sowing Keeps the Plot Full

The biggest mistake in summer is leaving gaps. Every time you lift a crop, sow something in its place. A bed cleared of early potatoes in July can carry winter kale, purple sprouting broccoli or a quick crop of salad leaves. Sow leeks in June for a winter and spring harvest, and keep a small tray of lettuce going every three weeks for a continuous cut.

Water deeply and less often, preferably in the early morning, and mulch around thirsty crops with grass clippings or compost. A weekly feed of diluted comfrey or nettle liquid keeps tomatoes, courgettes and peppers productive well into September.

Rotation Through the Year

Bring the whole calendar together and a rhythm appears. Legumes occupy one bed from spring into summer; brassicas follow them through autumn and winter; roots take over the next year; potatoes and alliums complete the cycle. Keep a simple notebook or a rough plan on the shed wall, recording what went where and how it fared.

Add compost each year, avoid growing the same family in the same spot, and your soil will grow steadily darker, crumblier and more alive. That is the real harvest of a thoughtful planting calendar — not just a full basket in August, but ground that gets better with every season you garden it.