Growing Peas in Scotland: The Complete Guide

Pisum sativum

Everything you need to grow peas in Scotland, from the first March sowing to picking the last pods in August. We have done the research so you don't have to.

Peas are one of the few crops that actually prefer our climate to the one further south. They flower best in cool weather and stop once summer heat arrives. In England that means a narrow window and a race against the heat. Here our cool summers keep them going longer, and the insect pests that bother pea growers elsewhere, pea moth and pea midge, are largely absent. Get the sowing right, give them something to climb, and they are one of the most dependable crops in a Scottish garden.

Why peas suit Scotland

Peas stop flowering once it gets properly warm, which in a southern English summer means a short season and a rush to get the crop in before it shuts down. Here the shutdown is gentler, because our summers rarely deliver the kind of sustained heat that stops a pea in its tracks. A maincrop sown in April will carry on producing through the cool weeks of July and August when an English equivalent would have finished weeks earlier.

There is a second advantage worth knowing. Pea moth and pea midge are not troublesome in Scotland. That little white maggot in the pod, the one gardeners further south learn to net against, is not something you need to worry about here. The pests you will see are the usual ones: pea aphid, thrips, slugs. All manageable.

Types: shelling, mangetout or sugarsnap

Peas fall into three types, and the difference is whether you eat the pod or just what is inside it.

• Shelling peas are the familiar ones. You shell them and eat the peas, not the pod. They come as first earlies, second earlies and maincrop, which sets the sowing-to-harvest time and how long they produce. Round-seeded varieties are hardier and suit early sowings. Wrinkled-seeded are sweeter and suit later sowings. First earlies crop in about 12 weeks, second earlies in 13 to 14, maincrops in 14 to 16.
• Mangetout are picked young and eaten whole, flat pod and all. They are the easiest of the group because there is no shelling and no waiting for the peas inside to swell. Pick at about 7.5cm long, just as the peas start to form.
• Sugarsnap peas sit between the two: the pod is edible but you pick them once the peas inside have formed, so they are plumper than a mangetout.

For Scotland a maincrop shelling pea and a mangetout or sugarsnap make a good pair. The maincrop keeps producing through the cool summer weeks, and the edible-pod types are quick and forgiving. If you only grow one type, a mangetout is the lowest-effort way to get peas onto a plate.

Varieties

Nobody trials pea varieties for Scottish conditions, so the picks below are our judgement, reasoning shown. These carry the RHS Award of Garden Merit, a UK-wide award, not a Scottish one.

Also worth considering

Soil and site

Peas want an open, sunny site and moisture-retentive soil that drains freely. Dig in at least two bucketfuls of well-rotted compost or manure per square metre a few weeks before sowing, to let the soil settle. Do not add fresh manure, and do not add nitrogen fertiliser. Peas fix their own nitrogen from the air through root nodules. Too much produces leaves at the expense of pods. Both RHS and Teagasc independently confirm this point.

What they will not tolerate is cold, wet, claggy soil at sowing time. That is a bigger constraint here than soil fertility. Peas also dislike heavy, wet ground that carries a risk of foot and root rot. Give them the lightest, best-drained bed you have.

Once the crop is finished, cut the tops off at ground level and dig the roots in. The nitrogen fixed in the nodules breaks down over winter, and the crop that follows peas in the rotation gets the benefit.

Sowing

Sow outdoors from March to July, once the soil reaches about 10°C. Push seeds about 5cm deep, spaced 5cm to 7.5cm apart in rows about 30cm apart. The key is succession: sow a short row every two or three weeks rather than one long one, and you get a steady supply from early summer into early autumn rather than a glut.

The March and July ends of that window need a caveat worth heeding. Do not sow into cold, wet soil. A seed in chilly March mud will rot. In most of Scotland that means late March or early April is the honest start. If spring is slow to arrive, warm the soil with cloches for a week before sowing. At the other end, a July sowing is perfectly possible here because our summers stay cool, and it gives you an early-autumn crop when the earlier sowings are finished.

Sow directly where the plants are to grow, because peas do not transplant well. For an early start you can sow in guttering indoors in February or March: fill a length of guttering with compost, sow in a double row, and slide the whole row out into a prepared drill when the plants are about 20cm tall. That buys you a couple of weeks' head start without disturbing the roots.

Dwarf types: sow in a flat-bottomed trench 5cm deep and 15cm wide, scattering the seeds across the full width in three staggered rows about 7.5cm apart.Taller types: sow in a single or double row with 30cm between rows. Generous spacing makes the plants easier to support and improves air circulation, which deters powdery mildew.

Protect seedlings from slugs and pigeons. Both will take a young pea plant before it has a chance to establish.

Support

Peas want something to climb, and they want it from the start. Put the support in before the stems reach 10cm. By the time they bend over and flop, it is too late. A row of peas laden with pods after a wet night weighs more than you think.

For shorter varieties, twiggy branches pushed firmly into the ground along the row are the traditional method and they work perfectly well. For taller varieties, and especially for a long row, use pea netting or chicken wire attached to posts or bamboo canes. Some varieties grow to 1.8m and become top-heavy in wet weather, so make the supports taller and sturdier than you think you need. Peas can technically be grown without staking, but it is messy and the pods are harder to pick.

Watering and feeding

Once pea plants are established and growing strongly, they rarely need watering except in prolonged dry spells. Give them a good watering once they start to flower, and again two weeks later. That is when the pods swell and the crop is made. Water the soil, not the leaves, because wet foliage encourages powdery mildew. Container peas dry out fast and need regular watering, but the harvest from a pot is usually small.

Feeding is rarely needed. Peas fix their own nitrogen from the air, and the compost dug in before sowing supplies everything else. Container-grown peas benefit from a high-potassium liquid feed once the first flowers appear.

Harvesting

First earlies are ready about 12 weeks after sowing. Second earlies take 13 to 14 weeks, maincrops 14 to 16. Mangetout and sugarsnap types are ready sooner because you pick them before the peas inside fully develop, at about 7.5cm long, just as the peas start to form.

Pick regularly and pick often. A pea plant that is picked clean keeps producing. One that is left to set mature seed shuts down, and the crop is over. Pods develop lower down first, so start at the bottom and work up. If you have a glut, pick everything and freeze the excess rather than leaving pods to harden on the plant.

Peas lose their sweetness within hours of picking, which is why frozen peas from the supermarket taste greener than fresh ones that have sat in a bowl all afternoon. Pick just before you plan to eat them, or blanch and freeze them the same day. The difference between a pea picked ten minutes ago and one picked yesterday is the reason people grow their own.

Common problems

• Seeds rotting rather than germinating. The soil was too cold and too wet. Wait for 10°C.
• Slugs go for seedlings, which is another reason to wait for warmer soil rather than sowing into a cold March bed where growth is slow and the slugs have the advantage.
• Mice will take newly sown pea seeds. Sowing indoors and planting out sidesteps the problem entirely. So does a July sowing, because the soil is warm and germination is fast.
• Pigeons eat young pea plants. A netting cage or fleece over the row until the plants are established is the simplest defence.
• Powdery mildew appears as a white dusty coating on the leaves, usually in dry weather or when plants are crowded. Good spacing, watering at the roots rather than over the leaves, and mildew-resistant varieties like Jaguar all help. It is unsightly more often than fatal.
• Pea moth. The little white maggot inside the pod is not something most Scottish growers need to worry about. SRUC field-scale guidance finds it and pea midge are not troublesome here.
• Collapsed rows after a wet night. Put the support in before the plants reach 10cm, and put it in properly.

Common questions

Sources