Welcome to Top of the Crops! Today, you will learn how to grow peas and mange trout in your polytunnel in the UK. For further expert gardening tips, be sure to check out our vast blog Polytunnel Gardening.
Peas are an important crop for many in temperate climate zones. Not only do they deliver a delicious yield, they are also legumes that fix nitrogen in the soil. Growing peas in a polytunnel will not only provide some home-grown sustenance but will also help ensure the long-term fertility of the space.
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Peas, Pisum sativum, offer us several different edible yields. There are a wide range of different cultivars that offer us edible shoots, pods, and seeds.
Peas are usually divided into different categories based on the yields that they provide. There are:
Mangetout, from which we eat the immature pods before the seeds begin to form inside.
Sugar snap peas, from which we eat the pods with their seeds inside while small and tender.
Shelling pea, garden pea types, from which we discard the pods and eat the seeds inside while they are fresh and green.
Dry/ soup peas, which are left for the seeds to mature fully, and from which we get dried peas, used as a pulse.
Peas can also be grown over short periods of time and harvested for pea shoots while they are still small and tender. Pea shoots are a quick crop that can potentially be harvested from a windowsill garden throughout the whole of the year.
To grow peas successfully, you need to provide them with the following basic conditions:
Full sun.
A moderately fertile, moist yet free-draining, neutral to alkaline soil or growing medium.
Peas are not at all difficult to grow. You can grow a huge variety of different peas from seed. Even complete beginners will find peas a straightforward crop to grow.
Peas can be sown indoors before young plants are transplanted to the garden, or then can be direct sown in the garden where they are to grow.
You can sow pea seeds indoors from early in the year, and continue sowing right up until June. Peas suitable for overwintering in a polytunnel can also be sown in the autumn, for an earlier harvest the following year.
You can also direct sow peas outdoors or in a polytunnel between around March and June, and, again, may also be able to sow some winter varieties under cover in autumn.
Sowing indoors can be a good idea as it protects the seeds from being eaten by mice or voles, which can be an issue in some areas.
If you are sowing indoors, you can do so into toilet roll tubes, small pots, or other recycled containers. The seeds should be sown within a moist but free-draining seed-starting potting mix to a depth of around 5cm.
Another time-saving idea involves sowing peas in a double row, with the seeds around 7.5cm apart, in a length of guttering filled with your potting mix. This makes it easy for you to transplant the seedlings as the whole lot can simply be slid out into a trench you prepare in a planting area.
Whichever method you choose, peas sown indoors are usually planted out in March or April once they are around 15-20cm tall.
Alternatively, you can direct sow. One common method is to sow peas in two parallel lines in a shallow trench around 22cm wide and approximately 3cm deep, spacing the peas around 5-10cm apart.
However, there are also other methods, such as broadcasting the peas within a shallow trench, that can work well for some varieties.
The precise way that peas are sown will often depend on the variety you have chosen, whether they are smaller or taller types, and the support they will require. Often, it is a good idea to get supports in place before sowing or planting out pea seedlings.
We'll take a look at support options for different types of peas a little later in this guide, so read on to find out more.
If you sowed peas indoors, these should be hardened off for a week or so before they are planted out into their final growing positions. Plant the peas around 7.5cm apart (though precise spacing can depend on the size of the variety) and in rows spaced to allow for support and harvesting access.
Firm the plants in gently and then water your new peas in well. A mulch of grass clippings or other nitrogen rich material spread around but not touching the peas may be beneficial to provide nitrogen and conserve soil moisture.
How and when you will harvest peas will obviously depend on which varieties you have grown and when you have sown them. Remember, sometimes you may be harvesting the young shoots, sometimes the immature pods, sometimes the fresh, shelled peas and sometimes the mature seeds for use as a pulse.
The main harvesting period is between June and October though pea shoots may potentially be harvested throughout the whole of the year when grown on a sunny windowsill indoors.
Early peas are typically harvested 12 weeks from sowing, second earlies from 13-14 weeks and maincrop peas in 14-16 weeks.
Fresh peas are best eaten as soon as possible after harvesting. Straight from the garden they will generally be sweetest and have the best flavour. Pea pods and shelled garden peas that cannot be eaten fresh however can be frozen for later use. Peas that are to be used as a pulse can be dried to store over the winter months.
You should have no difficulty finding plenty of recipes in which you can use mangetout, sugarsnaps, fresh shelled peas and dried peas in your kitchen. Aside from peas used as a pulse, peas are generally best cooked only briefly, if at all. Of course, they can also be great in salads.
Peas are generally not a crop that has a lot of problems, as long as they are grown in a suitable soil or growing medium, in full sun or only very light shade (only for maincrop types).
Often, problems relate to crops not being watered correctly, or to insufficient support which can lead to breakages, flopping, and damage to plants, and make peas more challenging to harvest.
Pests may sometimes also arise, and occasionally, peas may experience some fungal diseases. More on these in the common problem section below.
The right care for pea plants can help gardeners avoid many of the most common issues when growing these plants.
Peas do need to be watered during their very early growth and until they settle in. but once they are established, unless they are growing in pots and/or undercover, they will not need watering as natural rainfall will usually be sufficient.
It is beneficial in all cases, however, to water peas well when they start flowering and again a couple of weeks later to help with pod formation. Aim to keep the soil or growing medium moist but not waterlogged at this time.
Try to water at the base of the plants and not to wet the foliage. This can help reduce the chances of fungal diseases like powdery mildew taking hold.
As mentioned above, an organic mulch of grass clippings or other leafy green material around your peas can help retain soil moisture in summer and give the plants some nitrogen too. You can also add other organic mulches like compost too.
How to support peas is one of the most important questions for gardeners to ask when growing peas in their gardens. There are many different options, from trellises and pea netting, to simple bamboo cane wigwam structures, to twiggy sticks, to stakes and twine...
Which option is right will depend on whether you are growing taller, climbing peas or shorter bushier types. Taller peas will obviously need more support, with more points for their tendrils to cling onto. Shorter varieties can make do with just a few branching twigs inserted into the soil near them, or with stakes and lengths of twine around the edges of a wide row.
Some great mangetout and sugarsnap varieties include:
‘Delikata’
‘Snow Wind’
‘Cascadia’
'Delikett’
'Norli'
‘Sugar Ann’
‘Sugar Bon’
‘Sugar Lace’
And some shelling peas to consider include:
‘Hurst Green Shaft’
‘Jaguar’
‘Kelvedon Wonder’
‘Serge’
‘Show Perfection’
‘Spring’
‘Terrain’
‘Vivado’
All of the varieties listed above have an award of garden merit from the RHS.
As mentioned above, peas are generally not prone to serious problems and are easy to grow. However, they can encounter a number of pests and diseases.
In their early stages of growth, major problems can be slugs and snails, and birds like pigeons. Polytunnel growing, and covering the crop, can make it easier to avoid losses. Increasing biodiversity in your garden will also always help with pest problems, and help keep the ecosystem in balance.
Established plants may occasionally be damaged by pea moth, pea and bean weevils, or powdery mildew, but none of these issues will usually affect cropping to any significant degree as long as they are kept under control.
Even if you don't have a garden, or garden space is limited, peas can be an easy crop to grow. As we have already discussed, peas can be grown for pea shoots in even the most limited of spaces, even indoors on a sunny windowsill.
Gardeners with limited space can also potentially grow a range of smaller pea cultivars in pots. Mangetout and sugarsnap peas are often easiest and will give you a somewhat larger yield than shelling peas when you can only grow a few plants.
Peas work with bacteria in their root nodules in the growing season to fix nitrogen from the air. Some of this nitrogen is used by the plants themselves but some is released into the soil, where it may be of benefit to other plants nearby, and to plants following peas in rotation.
A healthy soil and organic mulches will be sufficient and peas won't need additional feeding.
Growing peas in a polytunnel where they are somewhat protected from birds and other 'pests' makes growing this easy crop even easier.
Grow peas in polytunnel beds or borders throughout much of the year, or grow smaller cultivars in pots. Some peas are also well suited to hanging baskets or other hanging containers.
Peas, as nitrogen fixing legumes, are helpful in companion planting and in crop rotation. Brassicas and other leafy greens will like the nitrogen when they follow peas in rotation. Leave pea roots in the ground at the end of the season.
Do peas need to climb?
Many pea varieties require support and will grow tall, using their tendrils to cling to structures. However, there are also bush varieties that may not need a structure to climb.
What is the best month to plant peas?
Peas sown indoors should be planted out in spring, as soon as the soil is workable and after the last frost date in your area.
How do you look after pea plants?
After sowing and planting peas in a suitable location, with support if needed, ensure to water them well, protect them until established, and then enjoy the harvest provided by the variety you have chosen.
How do you grow peas for beginners?
Beginners can start by growing pea shoots, mangetout, or sugarsnap peas. Choose a sunny spot with free-draining soil and monitor the crop for pests or problems. With careful attention, beginners should achieve rewarding yields.
40 Pea Recipes, Olive Magazine. [online] Available at:https://www.olivemagazine.com/recipes/collection/best-ever-pea-recipes/ [accessed 15/12/23]
