How to Grow Soya beans

Soya beans grow best in warmer parts of the UK, as they need a long hot summer to crop well. The short pods of small round beans can be harvested when still green and immature, as edamame beans, or allowed to mature for drying and using over winter.

Originating from South-East Asia, soya beans (Glycine max) need full sun, heat and plenty of moisture to produce a good crop in the UK. But as our climate warms and as new, more resilient varieties are introduced, they are becoming a more popular and viable crop here.

Soya plants produce short hairy pods containing two or three small rounded beans. These can be harvested at two different stages, from late summer into autumn:

• when the beans are the size of garden peas, still green and immature, for cooking and adding to salads, stir-fries and many other dishes. These are usually known as edamame beans
• when the pods are fully ripe and dry – the mature soya beans inside can be stored for use in stews and other hearty winter dishes

Soya beans can be grown from seed sown indoors or outside. They form bushy plants about 60cm (2ft) tall, depending on the variety, and don’t usually need supports. The beans are a good source of protein and fibre, but they must always be cooked before eating, to get rid of any natural toxins.

Soya beans generally need a long, hot summer, ideally 20–30°C (68–86°F), although some newer varieties can cope in cooler conditions. Choose a variety suitable for your local climate, otherwise results may be disappointing. Soya bean seeds are sometimes sold as edamame beans, which is the name given to the immature green beans, but these can be harvested as mature dried beans too. Only a few varieties are currently available in the UK.

What and where to buy

Soya and edamame bean seeds are available in some larger garden centres and from several online seed suppliers, but the choice of varieties is currently quite limited. Young plug plants

Seedlings or young plants grown singly in small modules, with the advantage that they can be transplanted with minimal root disturbance. Bedding plants and young veg plants are often sold as plug plants of various sizes, with smaller ones requiring more aftercare. They usually need to be potted up and grown on indoors until large enough to plant outside. may also be available in late spring and early summer, from similar sources.

Recommended Varieties

'Elena'

Said to be the best variety for the UK climate. Harvest from August to November.

Read more

'Envy'

Heavy-cropping plants up to 60cm (24in) tall. Harvest as green edamame beans or as mature soya beans.

Read more

'Black Jet'

A tough variety that crops well in poor summers. Image © Shutterstock

Read more

Choose a warm, open, sunny growing site, ideally with light, free-draining soil. Weed thoroughly, then fork in lots of home-made garden compost

Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. or well-rotted manure – at least two bucketfuls per square metre/yard. Ideally do this a few weeks before sowing or planting out, to allow the ground to settle. Alternatively, if you're practising no-dig, mulch

Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings. the soil ahead of sowing or planting directly into the mulch.

Soya beans can be sown indoors in April and May, or outdoors in May and June. Sowing indoors is generally a more reliable option – the warmth ensures good germination

Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light. rates and you can sow earlier, to give a longer growing season. It also ensures mice don’t eat the seeds, and keeps the seedlings

A seedling is a young plant grown from seed. out of reach of slugs and snails until larger and more robust.

Sowing indoors

In mid- to late spring, sow soya beans in small pots or modular trays filled with moist peat-free seed compost

Seed compost is a free-draining compost formulated for germinating seed. It often contains a mix of fine materials including sterilised loam, coir, coarse sand or grit. It contains low levels of nutrients, as high levels could damage seedlings. , inserting them 5cm (2in) deep. Place in a propagator

A propagator is a portable, lightweight structure usually plastic, with a vented or unvented lid to provide a humid, slightly warmer atmosphere. It is useful to help seeds germinate and root cuttings. It may have adjustable, thermostatic temperature control. , or cover with a clear polythene bag, and keep at 18–20°C (64–68°F). For more sowing tips, see our guides below.

Once seedlings

A seedling is a young plant grown from seed. appear, remove from the propagator or uncover, then keep in a warm, bright location, watering regularly. Move the seedlings into larger pots when roots appear through the drainage holes. They should be ready to plant out in late May or early June – see Planting, below.

Sowing outdoors

You can sow soya beans outdoors once the soil has warmed to at least 15°C (60°F) in late spring or early summer. Sow seeds 5cm (2in) deep, 15cm (6in) apart, in rows 45cm (18in) apart, then cover with cloches or plastic-free fleece. Protect the seedlings

A seedling is a young plant grown from seed. from slugs and snails, especially in damp weather.

Wait until early summer, when temperatures are around 15°C (60°F), before planting indoor-raised soya plants or young bought plants outside. Harden them off, to avoid a check in growth, and make sure your planting site is prepared in advance (See Preparing the ground above).

Water the young soya plants well, both before and after planting, and space them 15cm (6in) apart, with 45cm (18in) between rows. After watering in, cover the plants with cloches or plastic-free fleece to keep them warm while they get established.

Watering

Soya beans are thirsty plants and crop best when watered regularly in dry spells, especially once they start to flower and form pods. To reduce competition for water, keep the soil around your plants free from weeds.

Mulching

Spread a deep mulch

Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings. of garden compost around the plants after planting to help hold moisture in the soil and deter weeds.

Supporting plants

Most soya bean varieties sold in the UK grow to about 60cm (2ft) tall and are self-supporting. But in a windy site, or if you choose a taller variety, insert sturdy bamboo canes at the ends of the rows and loop string around them to hold the plants upright.

You can harvest these nutritious beans either unripe as edamame beans or fully ripe as dried soya beans.

Edamame beans are immature soya beans, harvested in summer when the pods are still green, with plump green beans inside. They can either be shelled or cooked in the pods (then shelled), and must be boiled for at least ten minutes to destroy their natural toxins.

Mature soya beans are ready for harvesting from late September, when the leaves start to fall from the plants, often leaving just brown stems with lots of hanging pods. The pods remain weatherproof during autumn, so you can pick as needed. After harvesting, remove the beans from their dry pods, then either cook straight away or spread them out on a tray indoors to dry fully. Store the dry beans in an airtight container for use over winter. As with the immature beans, cook mature soya beans thoroughly to remove any natural toxins.

Once harvesting has finished, cut plants down to the base and compost

Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. them. However, as legumes (peas, beans and related plants) fix nitrogen from the air at their roots, leave these in the ground to boost soil nitrogen levels.

Soya beans are easy to grow and generally trouble-free, as long as they’re kept warm and well watered throughout the growing season. In cool summers or colder regions, cropping may be reduced. Take care not to plant them out too early, and protect them with cloches or plastic-free fleece to keep them warm while they get established. Seedlings

A seedling is a young plant grown from seed. and young plants are vulnerable to slugs and snails – see Common problems, below.

Common Problems

Downy mildews

Downy mildews can spoil the appearance of ornamental plants and affect the yield and quality of edible crops. Control depends on cultural techniques a...

Read more

Plant viruses

Plant viruses affect many plants and cause a wide range of discolourations and distortions in leaves, shoots, stems and flowers, but rarely kill the p...

Read more

Powdery mildews

Powdery mildews are a group of related fungi which attack a wide range of plants, causing a white, dusty coating on leaves, stems and flowers.

Read more

Slugs and snails

Slugs and snails are common garden animals, and they are well suited to the damp, mild climate of the UK. A few species feed on garden plants, but mos...

Read more

Showing 3 out of 4 recommended

Show more