Seasonal vegetables in the garden: sowing and harvesting calendar

A garden that feeds you from April to February doesn’t happen by accident. It happens because someone, at some point in the dead of winter, sat down with a calendar, a stack of seed packets and a pencil, and worked out what goes where — and when.

Most disappointing harvests have nothing to do with bad soil or bad luck. They come from good intentions meeting bad timing. Seeds dropped into cold, soggy ground in March rot instead of sprouting. Lettuce sown in one enthusiastic batch in May turns into a hundred heads at once, then nothing for weeks. Tomatoes planted out too early sulk in chilly soil while a later planting overtakes them.

This guide walks through the whole year, season by season, with the practical logic behind each sowing window and each harvest moment. No rigid rules that only work in one postcode — instead, a framework you can bend to your own patch of ground, whether that’s a windswept allotment, a sheltered back garden or a few deep containers on a sunny terrace.

Table of contents

• Start with your own rhythm: frost dates, microclimate and day length
• The four sowing windows and when to use each one
• Spring: cool-season crops and the first outdoor sowings
• Summer: warmth-loving crops and the art of succession
• Autumn: the second harvest and crops that overwinter
• Winter: protection, slow growth and next year’s plan
• Harvesting at peak: reading the signs and storing the surplus
• Frequently asked questions
• Putting the calendar to work

Start with your own rhythm: frost dates, microclimate and day length

Every sowing calendar in every book is a rough sketch of somebody else’s garden. The useful version is the one you build for your own ground, and it starts with two dates: the average last frost of spring and the average first frost of autumn. Those two markers define the length of your growing season, and everything else hangs off them.

They are averages, not promises. A late frost can arrive a fortnight after the “safe” date, and an early one can cut a warm autumn short. That’s why the smartest approach is to work in windows rather than single days. Sow hardy crops two to three weeks before the expected last frost, tender crops a week or two after it, and keep a roll of horticultural fleece within arm’s reach until the risk has genuinely passed.

Then there’s your microclimate — the local quirks that shift those dates by weeks. A garden on a south-facing slope, sheltered by a wall or a hedge, warms up fast and drains well. A plot at the bottom of a hill, where cold air pools on still nights, behaves like somewhere much further north. Two gardens a short drive apart can easily differ by three weeks in what they can sow and when.

A concrete example: a raised bed against a south-facing brick wall may hold enough warmth for an early sowing of radishes and spinach in late February, while an open bed thirty metres away is still frozen solid at the same moment. The wall radiates stored heat overnight, and the soil behind it stays workable. Same garden, same seeds, three weeks apart.

Day length matters too, and it’s the factor gardeners forget most often. Spinach, rocket and coriander sown in the long days of June will bolt — run to flower — almost before you’ve picked a leaf. Sow the same seeds in September and they’ll sit happily for months. The calendar isn’t just about temperature; it’s about hours of light.

My recommendation: keep a simple notebook. Record the date of the last spring frost, the first autumn frost, and the day your first tomato ripens. After three years you’ll have a personal calendar more accurate than any chart, because it’s measured in your soil, under your sky.

The four sowing windows and when to use each one

Almost every vegetable you’ll ever grow fits into one of four approaches. Understanding which one suits which crop — and which moment — removes most of the guesswork.

Direct sowing means putting seed straight into the ground where the plant will live. It suits crops that resent root disturbance: carrots, parsnips, beetroot, radishes, spinach, beans, peas, sweetcorn and most salad leaves. It’s cheap, fast and low-fuss, but it leaves young seedlings exposed to slugs, birds and dry spells.

Indoor sowing and transplanting gives you a head start. You raise seedlings in trays or modules in warmth, then move them out once the weather allows. Tomatoes, peppers, aubergines, brassicas, leeks, celery and squash all benefit. The trade-off is space, attention and the need to harden plants off gradually before planting out — a week of short daytime trips outside, extended little by little.

Succession sowing is the technique that separates a garden with a glut from one with a steady supply. Instead of sowing a whole row of lettuce in one go, you sow a short row every ten days to a fortnight through the season. The same logic works for radishes, spinach, beetroot, carrots and bush beans. Small, frequent sowings flatten the harvest curve.

Overwintering and autumn sowing exploits the fact that some crops grow slowly through the cold months and explode into growth in early spring. Broad beans, garlic, winter lettuce, mâche and hardy Asian greens all fit here.

A concrete example: a single two-metre row of radishes sown on the first of May delivers perhaps forty roots, all ready within the same ten days. Nobody eats forty radishes in ten days. Split that same packet into four short sowings across May and June and you’ll pick a handful every week for two months — same seed, same space, far better eating.

Spring: cool-season crops and the first outdoor sowings

Spring is a test of patience, and most gardeners fail it. The first warm afternoon in March tempts you to dig, sow and plant everything at once. The soil, though, is still cold and often waterlogged, and seeds sitting in cold wet ground simply rot.

The reliable test is physical, not calendrical. Pick up a handful of soil and squeeze it. If it forms a sticky ball that holds together and glistens, it’s too wet — walking on it will compact it into brick, and sowing into it is a gamble. If it crumbles apart as you open your hand, it’s ready. Work from the lightest, best-drained beds first and leave the heavy clay until last.

Hardy crops can go in early: broad beans, peas, spinach, chard, onions and shallots, early carrots, radishes, turnips, and brassicas like cabbage and broccoli raised indoors and planted out once they’ve got four or five true leaves. Lettuce and rocket can follow as soon as the soil is workable, though a cloche or a length of fleece will speed germination noticeably and protect against a late frost.

A concrete example: peas sown into cold, saturated soil in early March often sit for three weeks and then fail entirely — the seed coats split and rot. The same peas sown three weeks later, into soil that has dried and warmed a little, germinate in ten days and outgrow the earlier sowing within a fortnight. Waiting genuinely wins the race.

Toward the end of spring, the tender crops come into play — but only once the soil has warmed properly and the frost risk has passed. Tomatoes, courgettes, cucumbers, sweetcorn, beans and squash all sit and sulk in cold ground. There’s no prize for planting them first.

Summer: warmth-loving crops and the art of succession

By early summer the garden shifts gear. Growth is fast, water demand is high, and the main risks change from cold to drought and pests. This is the season for the crops that define a kitchen garden: tomatoes, courgettes, French and runner beans, cucumbers, peppers, aubergines, sweetcorn and squash.

Watering strategy matters more now than at any other point in the year. A deep soak two or three times a week beats a light sprinkle every evening, because it drives roots downward instead of encouraging them to sit near the surface. Water in the morning where you can, and aim at the soil rather than the leaves — wet foliage overnight is an open invitation to mildew. A layer of mulch, whether compost, straw or grass clippings, cuts evaporation dramatically and keeps the soil temperature steadier.

Here’s the part many gardeners miss: summer is also a sowing season, not just a growing one. Everything you sow in July and early August becomes your autumn and winter supply. Winter kale, purple sprouting broccoli, turnips, beetroot, winter lettuce, spinach and Asian greens all go in now. Beds emptied by early potatoes or broad beans are perfect for this — clear them, add a little compost, and sow straight away rather than leaving the ground bare.

A concrete example: a tomato plant set out into cool soil in mid-May will often sit almost motionless for two weeks, its leaves turning a bluish-purple as the roots struggle. A plant set out three weeks later into properly warm soil grows away without a pause — and by August the later planting has usually caught up and overtaken the early one.

Keep picking, too. Courgettes, beans and cucumbers all respond to regular harvesting by producing more. Leave a courgette to swell into a marrow and the plant quietly slows down.

Autumn: the second harvest and crops that overwinter

Autumn is the most underrated season in the vegetable garden. Growth slows but doesn’t stop, the soil is still warm, and rainfall usually does the watering for you. Everything planted now is effectively stored in the ground, ready to be harvested through the cold months.

Salad leaves come into their own again. Rocket, spinach, mâche, winter lettuces and land cress all thrive in the shorter, cooler days and won’t bolt the way their summer counterparts do. Sow them in batches through September and early October for a supply that lasts into the new year. Oriental greens — mizuna, pak choi, mustard greens — are fast, hardy and forgiving.

Garlic and overwintering broad beans are the classic autumn plantings. Garlic needs a spell of cold to divide properly into cloves, which is why autumn planting generally gives better bulbs than spring planting. Broad beans sown in October or November establish strong roots before the cold and produce pods weeks ahead of spring-sown plants — though in very exposed gardens, a little wind protection helps them through the worst of the weather.

A concrete example: garlic planted in late October roots gently through the mild weeks of autumn, sits dormant through the hardest frosts, then surges in March. The same variety planted in February tends to produce smaller, less well-divided bulbs — the cold period simply wasn’t long enough.

Bare soil is wasted soil. Where a bed has finished for the year and you have nothing to plant, sow a green manure — field beans, grazing rye, phacelia or mustard — and dig it in during early spring. It suppresses weeds, protects the soil surface from winter rain and adds organic matter when it’s turned under.

Winter: protection, slow growth and next year’s plan

Winter gardening is less about growing and more about harvesting and protecting. Leeks, parsnips, kale, Brussels sprouts, winter cabbage, Jerusalem artichokes and root crops still sitting in the ground will feed you through the coldest weeks, often tasting better for the cold.

Protection is mostly about water and wind rather than pure temperature. Waterlogging kills more winter crops than frost does, so raised beds and well-drained ground make a real difference. A cloche, a cold frame or a double layer of fleece can lift the temperature around a plant by enough to keep winter salads cropping. Mulch around hardy plants to keep the soil from freezing and thawing repeatedly, which heaves roots out of the ground.

A concrete example: parsnips left in the ground until after the first hard frosts taste noticeably sweeter than those lifted in October. The cold converts stored starch into sugar — a natural antifreeze mechanism in the root. Leave them where they are and lift them as you need them.

Use the quiet months for the jobs that pay off later. Clean and sharpen tools. Empty, scrub and stack pots. Spread compost or well-rotted manure over empty beds and let the worms work it in. Order seeds before the varieties you want sell out. And write your rotation plan: never grow the same crop family in the same bed two years running, because pests and diseases build up in the soil. Brassicas follow legumes, roots follow brassicas, legumes follow roots — a simple three-year cycle keeps the ground healthy.

If you have indoor space and a bright windowsill, late winter is also the moment to start the slowest crops: onions from seed, peppers, aubergines and early tomatoes. A little head start in February pays off handsomely in July.

Harvesting at peak: reading the signs and storing the surplus

Knowing when to pick is a skill, and it’s learned by looking rather than by reading the calendar. Courgettes are best at 10 to 15 centimetres, while the skin is glossy and the flesh firm. French beans should snap cleanly; if the pod bends like a wire, it’s gone past its best. Peas are ready when the pods feel plump but before they show the shape of every individual pea through the skin.

Lettuce and salad leaves are at their sweetest before the plant starts to send up a flower stem. Once that central shoot appears, the leaves turn bitter. Cut whole heads in the early morning, when the leaves are turgid and cool, and they’ll keep far longer in the fridge than anything cut at midday.

Root crops are forgiving — most can stay in the ground until you need them, which is the simplest storage system ever invented. Where you do lift them, twist off the leaves rather than cutting them, and store the roots in boxes of slightly damp sand in a cool, dark, frost-free place. Onions and shallots need curing first: a fortnight somewhere dry and airy until the necks are papery and the skins rustle. Winter squash wants a week or two of warmth to harden its skin before going into storage.

A concrete example: a basket of French beans left in the sun on a warm afternoon loses its snap within hours and goes limp in the fridge. The same beans, cooled quickly and stored in a perforated bag in the vegetable drawer, stay crisp for the best part of a week. Speed from plant to cool place is the single biggest factor in how good your harvest tastes.

Frequently asked questions

What happens if I miss a sowing window?

Less than you’d think. Almost every crop has a range of viable dates, and a late sowing usually just means a later harvest rather than no harvest at all. What changes is the tail end of the season — a crop sown a month late may not have time to mature before the cold arrives. In that case, switch to a faster-maturing variety or a hardier crop. Missed the main carrot sowing in June? Sow a quick-growing salad crop instead and put carrots in next spring.

Can I follow a sowing calendar in containers?

Yes, with two adjustments. Containers warm up faster than open ground in spring, which is an advantage, but they also dry out and cool down faster, which is not. Choose compact varieties, use a generous volume of potting mix, and expect to water far more often than you would in a bed. Salad leaves, radishes, dwarf beans, chillies, herbs and cherry tomatoes all do well in pots on a sunny patio.

How do I avoid a glut followed by nothing?

Sow little and often. Divide each packet into small batches and sow one batch every ten to fourteen days through the appropriate window, rather than emptying the packet in a single session. The same principle applies to planting out: stagger your transplants across two or three weeks. You’ll trade one frantic week of preserving for months of steady picking.

Do I need a greenhouse or polytunnel?

Not for most crops. A greenhouse extends your season at both ends and makes raising tender seedlings far easier, but a bright windowsill, a cold frame and a roll of fleece will get you a long way. Many excellent kitchen gardens are grown entirely outdoors, with a bit of protection used only for early sowings and winter salads.

How do I remember what I sowed where?

Label everything at the moment of sowing — not later, because later never comes. A simple wooden or plastic tag with the crop name and the date is enough. Alongside that, keep a rough plan of your beds drawn on paper and note what went where each year. That record is what makes crop rotation possible and stops you repeating the same mistakes season after season.

Putting the calendar to work

A seasonal sowing and harvesting calendar isn’t a rulebook — it’s a rhythm. Learn your own frost dates, notice how your soil warms and drains, and sow in small batches rather than one big push. Work with the four windows: direct sowing for roots and salads, indoor sowing for the tender crops, succession sowing for anything you want to eat steadily, and autumn sowing for next year’s head start.

If you take one thing away, make it this: the garden rewards the person who waits. Wait for the soil to crumble rather than stick. Wait for the frost risk to pass before planting tomatoes. Wait for the pods to plump before picking peas. Timing, more than any tool or technique, is what turns a patch of ground into a supply of food.

From here, the natural next steps are crop rotation and soil health — the two subjects that determine whether next year’s calendar works as well as this year’s. Companion planting, seed starting indoors and water-wise summer watering all build on the same seasonal logic, and each one will make the calendar easier to follow.

Last updated 2026-09-25

Written by our editorial team at WiseHomeGuides, home and pet specialists.

Written by Rémy Bully

WiseHomeGuides publishes practical guides, comparisons and independent tests for home, bedding, garden and pets.

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