How to grow beans and peas

Legumes fix nitrogen from the air into the soil through their roots — making them genuinely good for your garden as well as for your dinner plate. Grow them, pick them regularly, and let the soil do the rest.

Why legumes are good for your soil

Beans and peas belong to the legume family (Fabaceae), and they share a remarkable biological partnership with soil bacteria — primarily species of Rhizobium and related genera. These bacteria colonise small nodules on the plant's roots and fix atmospheric nitrogen: converting nitrogen gas from the air into ammonium compounds that the plant can absorb and use. In return, the plant provides the bacteria with sugars produced through photosynthesis.

This nitrogen fixation happens all season long. At the end of the growing season, when you pull up your bean or pea plants, the root nodules release their fixed nitrogen into the soil. If you cut the plants at soil level rather than pulling them, the roots and their nitrogen-rich nodules decompose in the ground, enriching it further.

Traditional crop rotation places a legume crop before a hungry nitrogen-demanding crop — brassicas (cabbages, kale, broccoli) in particular benefit enormously from following legumes in a rotation. This is one of the most practical and well-evidenced principles in vegetable gardening. For more on building soil health without digging, see our no-dig gardening guide.

It's worth noting that the amount of nitrogen fixed varies with conditions — legumes in good, inoculated soil with proper moisture fix more than those in poor or waterlogged conditions. But even a modest contribution from a legume crop is a meaningful one, and it comes for free.

Types — peas, broad beans, French beans, runner beans

The legume family contains a wide range of vegetables with different growing habits, timings and culinary uses. Understanding what you're growing helps you care for it correctly.

• Peas (Pisum sativum) — grown for their sweet seeds eaten fresh (shelling peas), for entire tender pods eaten whole (mangetout and sugar snap), or dried for storage. Peas prefer cool weather and are one of the first crops you can sow outdoors in late winter or early spring in temperate climates. They dislike heat — in warm climates, grow them in the cooler months. Height varies from dwarf varieties (45 cm) to tall climbing types (1.5 m or more).
• Broad beans / fava beans (Vicia faba) — hardy, cool-season legumes that can be sown in autumn (in mild-winter climates) or early spring. They produce large, filling pods with creamy beans inside. Broad beans are among the most winter-hardy vegetables and can survive light frosts. Dwarf varieties (30–40 cm) need little support; taller varieties can reach 1.2 m and need staking. They are the only legume that thrives in cold soil.
• French beans / green beans (Phaseolus vulgaris) — tender crops that must not be exposed to frost. Sow after the last frost in your area. Available as climbing (pole) types reaching 1.8 m, which need support, or dwarf (bush) types that are self-supporting. Both produce their main crop relatively quickly once established. Climbing types produce over a longer period. Pods are harvested young and eaten whole (including when flat-podded or haricot types are left to dry).
• Runner beans (Phaseolus coccineus) — vigorous, frost-tender, reliably heavy-cropping climbing plants that can reach 2.5 m or more. They are primarily climbing plants — dwarf forms exist but are far less common. Runner beans produce attractive red, white or bicoloured flowers that are also visited enthusiastically by bumblebees. They need substantial support and plenty of water at flowering. The pods are harvested young, before they become stringy.
• Borlotti and haricot beans — varieties of Phaseolus vulgaris grown to let the pods dry on the plant. The seeds are shelled when fully dry and stored for use through winter. They are grown like French beans but with a much longer growing window before harvest.

Supports — what each type needs

Getting the support structure right before you sow is one of the most important practical steps in growing legumes. Trying to erect canes and netting around established plants is awkward and risks damaging stems and roots. Put supports in place first.

• Climbing peas: peas climb by tendrils that wrap around thin supports — twiggy sticks (pea sticks), fine netting, mesh or even rough-textured string. They don't need the same robust support as beans. A framework of pea sticks or a section of wire netting supported by canes is ideal. Dwarf peas may only need pea sticks pushed in alongside them for a little steadying.
• Broad beans: short varieties may not need support at all. Taller varieties in exposed positions can be supported with a simple frame — canes at each corner of the row with string tied around them at 30 cm intervals as the plants grow. This stops them toppling in wind.
• Climbing French beans: twine around canes, a wigwam of bamboo canes, or a framework similar to runner beans. They are not quite as vigorous as runner beans and don't need quite as heavy a structure.
• Runner beans: the most demanding in terms of support. A traditional double row of bamboo canes crossed and tied at the top is the classic solution — space canes 25–30 cm apart within the row, cross them at 1.5–2 m height, and tie a horizontal cane along the apex for stability. Alternatively, a wigwam of canes in a circle suits a small number of plants. Whatever structure you use, ensure it is very firmly anchored — a fully grown runner bean in a windstorm exerts a surprising amount of force.

Direct sowing vs modules — and timing

Beans and peas can be sown direct in the ground or started in modules or deep pots indoors. Both approaches work; the best choice depends on your conditions and the type you're growing.

Direct sowing is simple and works well for all legumes. Sow seeds 4–5 cm deep at the appropriate spacing. The large seeds germinate reliably in warm, moist soil. The disadvantages are that mice love pea and bean seeds and will dig them up, and slugs can devastate seedlings just emerging from the soil.

Module or pot sowing indoors produces transplants that are more robust when they go into the ground. Sow in deep modules or individual pots — legume roots don't like being cramped or disturbed. A cardboard inner tube from a toilet roll makes a biodegradable module that you can plant whole, preventing root disturbance entirely. Transplant when plants are 5–8 cm tall.

1. Erect your support structure. Put canes, netting, or a wigwam in place before sowing so you don't disturb roots later.
2. Sow at the correct depth and spacing. For climbing French beans and runner beans: sow 5 cm deep, 15–20 cm apart at the base of supports. For dwarf French beans: 5 cm deep, 15 cm apart in rows 30–45 cm apart. For peas: 4–5 cm deep, 5–7 cm apart in a wide flat drill or in double rows. For broad beans: 5 cm deep, 20–25 cm apart.
3. Protect from mice and birds. Lay fine wire mesh or twiggy branches over newly sown rows. A cloche or fleece cover also helps. Once seedlings are 10 cm tall, most birds lose interest.
4. Water in well and keep moist until germinated. Legume seeds need consistent moisture to germinate. Water gently after sowing and keep the soil moist but not waterlogged until seedlings emerge.
5. Guide first growth to supports. Once seedlings are a few centimetres tall, gently guide them towards the support structure. Peas will find their own way with tendrils; runner beans twine naturally.
6. Pinch out tips of broad beans when in full flower. Removing the top 7–10 cm of broad bean stems when the plants are in full flower reduces the risk of blackfly infestation (blackfly love the soft growing tips) and concentrates the plant's energy into pod development.

Succession sowing for a steady harvest

All legumes have a limited cropping window. Peas in particular produce their main harvest over a few weeks and are then finished. Without succession sowing, you get a glut followed by nothing for the rest of the season.

Making two or three sowings at intervals of two to three weeks spreads the harvest over a much longer period. Stagger sowings of French beans from after the last frost date through midsummer for pods from early summer to the first frosts. With peas, make an early sowing under cover in late winter for the first harvest, followed by one or two outdoor sowings in spring. A final late-summer sowing of a quick-maturing pea variety can give a small autumn harvest in many climates.

Runner beans are a little different — they are a longer-season crop that, once established, will produce for many weeks if picked consistently. A single sowing is often sufficient, though a second sowing a few weeks later extends the season slightly.

Watering — especially at flowering

Legumes are relatively drought-tolerant during early vegetative growth — they don't need heavy watering at this stage. The critical watering window is when the plants are in flower and setting pods. At this point, water stress directly reduces pod set and yield.

• Runner beans are the most sensitive to water stress at flowering. They are famous for dropping their flowers in hot, dry weather, resulting in bare patches on the plant where pods should be. Water deeply and consistently during flowering — this is more important than any other care you can give them. Mulching the root zone helps retain moisture between watering.
• Climbing and dwarf French beans benefit from regular watering at flowering, though they're slightly more tolerant of short dry spells than runner beans.
• Peas need consistent moisture throughout, but pod fill — the period when seeds are swelling inside the pods — is the other critical time alongside flowering. Water well during this stage for plump, sweet peas.
• Broad beans are the most drought-tolerant legume and may need little additional watering in a reasonable season, but in a dry spring water them when the pods are forming.

Pick regularly to keep plants cropping

The principle that applies to courgettes also applies here: regular picking signals to the plant that its reproductive work is not done, prompting it to produce more flowers and pods. Leaving pods to mature fully on the plant — especially if they start to dry and harden — tells the plant its job is complete and it slows or stops producing.

• Pick French beans when the pods are long and slim but before the seeds inside create visible lumps in the pod wall. At this stage they're most tender and flavourful.
• Pick runner beans while the pods are still flat and the beans inside are not yet bulging — typically at 15–20 cm long, before they become stringy.
• Harvest peas when pods are plump and filled but before they start to wrinkle or feel hard. Open a pod and taste — there's no more accurate test.
• Mangetout and sugar snap types should be harvested when pods are fully formed but seeds are still very small and flat inside.
• Broad beans: harvest when the pods are well-filled and the scar on each bean is white or cream. Once the scar turns dark, the beans have become starchy and are better used dried or in slow-cooked dishes.
• Check plants every two or three days at peak season — pods develop quickly in warm, humid weather.

Pests — mice, blackfly and birds

Legumes attract a predictable set of pests, most of which can be managed effectively with simple methods.

• Mice: the most damaging pest at the sowing stage. Mice have a particular fondness for pea and bean seeds and will excavate an entire row overnight. Physical barriers are the most effective solution — lay fine wire mesh directly over the sown row, or use mouse traps near the bed. Module sowing indoors entirely avoids this problem.
• Birds: pigeons and other birds will eat emerging seedlings and young plants, especially in the hungry months before other food is available. Cover rows with netting until plants are established (roughly 15 cm tall). String or netting over the tops of growing peas deters birds from landing.
• Blackfly (black bean aphid): the most common summer pest of broad beans and sometimes French and runner beans. Dense colonies of small black aphids cluster on the soft growing tips of broad beans in late spring and early summer, and can spread to flowers and developing pods. The best management is: pinch out the soft growing tips of broad beans as soon as the plants are in full flower (this removes the most vulnerable growth and the preferred habitat); inspect plants regularly and squash colonies with your fingers before they expand; encourage natural predators — ladybirds, lacewings and hoverflies all eat aphids. See our natural pest control guide for more on supporting beneficial insects.
• Pea moth (Cydia nigricana): a small moth that lays eggs near pea flowers; the larvae tunnel into developing pods and eat the seeds. You may not notice until you shell the peas. The most practical control is to cover pea plants with fine mesh during flowering, or to sow early varieties that have finished flowering before the main moth flight period (mid-summer in many areas). Pheromone traps are available to monitor moth presence.
• Slugs: a serious threat to seedlings and young plants. The same approaches apply as for other vegetables — go out after dark to collect slugs, use copper barriers, apply iron phosphate bait, or protect individual plants with collars.

Saving seed from beans and peas

Beans and peas are among the easiest vegetables for seed saving, making them a perfect starting point if you're new to the practice. They are naturally self-pollinating — the flower pollinates itself before it even opens in most cases — which means varieties stay true to type year after year without special isolation measures (though growing very different varieties right next to each other can occasionally lead to some crossing).

To save seed:

• Select the healthiest, most vigorous plants with the best pods. The plants you save seed from become the parent generation of next year's crop, so it's worth being selective.
• Leave the chosen pods on the plant well beyond the eating stage. The pods should turn papery and dry, and you should be able to hear the seeds rattling inside. Don't harvest them until they're fully dry, ideally on a dry day.
• If the season ends before pods can dry fully on the plant — common in wet, cool climates — pull entire plants and hang them upside down in a dry, well-ventilated space indoors. The pods will continue to dry in storage.
• Shell the dried seeds and lay them out in a single layer on paper or a tray for two to four weeks of further drying indoors before storing. Inadequate drying before storage is the main cause of poor germination the following year.
• Store in paper envelopes (not airtight plastic, which traps residual moisture) in a cool, dark, dry place. Label with variety name and year. Bean and pea seed typically remains viable for three to five years in good storage conditions, though germination rates decline over time.

For a full guide to selecting, drying and storing vegetable seeds, see our seed saving guide.

Beans and peas checklist

• Erect supports before sowing climbing types — canes, netting or a wigwam.
• Sow at the correct depth (4–5 cm) and spacing for your type.
• Protect newly sown seeds from mice with wire mesh or sow in modules indoors.
• Cover seedlings with netting until established to deter birds.
• Water consistently at flowering and pod-fill stages — this is when yield is determined.
• Pinch out the soft tips of broad beans when in full flower to reduce blackfly risk.
• Pick pods regularly — every two to three days at peak season.
• Succession sow peas and French beans every 2–3 weeks for a continuous harvest.
• Cut plants at soil level at the end of the season — leave the nitrogen-fixing roots to compost in the ground.
• Save seed from the best plants for next year's sowing.