Soya beans may seem like an exotic vegetable to consider planting in your permaculture plot, and its origins in South East Asia would suggest that it is not necessarily suited to growing in more temperate climes. However, as long as you have a reasonably long, hot summer (the seeds take between 65 and 85 days to mature to their harvestable state), you should be able to grow this great source of plant protein on your site. Besides the high protein content, soya beans are also a god source of iron, calcium and fiber. One of the great benefits of soya beans is that they are self-pollinating annuals, so you should be able to get a good crop from just a few plants and be able to harvest year after year.
There are thousands of varieties of soya beans available to cultivate. Talk to local growers and gardening societies to find out the best ones for your location. Some popular varieties include Ustie; which is a cultivar that will do well even in more temperate summers; Black Jet, which is renowned for its hardiness; Envy, which is well known for the heaviness of its crops; and Cowrie, which reaches maturity quicker than a lot of other varieties.
Soya beans need to be planted in a position that receives full sun for at least the majority of the day. They will still grow in partial shade, but the crop is likely to be thinner with each bean pod being smaller than those on specimens receiving full sunshine. Protection from strong winds is also advised as soya bean plants develop shallow, horizontal root systems. Soya bean plants can be grown in containers; however, each individual plant would need a container with a minimum of 8 square inches, so they are not very space-efficient as a container crop.
Soya beans favor a soil rich in organic matter so that nitrogen levels are high. This helps them to set good crops of bean pods. Prior to planting add some compost and, if possible, some well-rotted manure to the soil. Not only will this give the soya bean plants all the nutrients they need to survive and thrive, it will also help to make the soil well drained (while soya beans like moist soil, they do not do well if the soil is waterlogged). A soil pH of between 6.0 and 6.8 is ideal, and again this can probably be attained by the addition of plenty of compost. It should be noted, however, that soya bean plants can grow in poor soils; they just won’t set a good harvest crop. As such, permaculture gardeners may want to consider them as a cover crop if looking to cover exposed soil over the summer period. The plants can then be cut and left in the fall to provide green mulch.
Plant your soya bean seeds early in the spring, but only after the all risk of frost for the season has passed. Sowing planting-of-beans-254075_640around two weeks after the average last frost date should ensure you don’t jeopardize the crop becoming affected by surprise freezing temperatures, and that you have allowed the soil to warm up slightly after the privations of winter, so the seeds can get a good start in life (they will not germinate in cold soil).
Soya bean plants can grow as high as four feet so they need some space to grow into as they mature. When sowing your seeds, leave approximately 6 inches between seeds. Each seed should be planted at a depth of around 3 inches (if you have quite heavy soils with a higher proportion of clay, plant the seeds at around 2 inches deep so that they do not have to struggle too much to reach the soil surface as they germinate). Water after sowing, but not excessively (too much water at this early stage can cause the seeds to crack). If planting with companions, consider potatoes, cucumbers, corn and celery, while avoiding too close a proximity to alliums like onion and garlic.
Water the garden beds containing the soya bean seeds evenly and lightly – just enough to keep the soil moist – until the plants breach the surface of the soil. As the flowers form, followed by the pods, water regularly to help pod formation, but avoid watering from overhead, as this can damage and dislodge both flowers and pods. As such, soya bean plants lend themselves to a drip irrigation system, particularly if combined with a rainwater harvesting system. Laying mulch down after the plants have reached a few inches in height can benefit them greatly in terms of preserving soil moisture and preventing weeds from competing with the plants for soil nutrients. Wood chips or straw make good mulch for soya beans.
There are two types of harvesting you can do with soya beans – one is for using the beans fresh and one is for using them dried. Fresh soya beans are ready to harvest when the pods are still green and the seeds are starting to feel plump, typically in late summer or early fall. You can harvest as required, and unshelled green pods will keep for around a week in the refrigerator. These pods can be cooked (soya beans cannot be eaten raw as they contain a toxin harmful to humans – a toxin that is destroyed by 10 minutes in boiling water) either as they are, or you can shell the beans and discard the pods. As the harvesting season progresses, the foliage of the soya bean plant will turn more yellow and brown and the pods will be plumper. You can still use these beans fresh, but it is advisable to shell the beans before use. After 100 days or so, the beans are only really suitable for use dried. For this, pull up the whole plant and hang upside down in a cool, dry location until completely dry. Then shell the beans and discard the pods. Store in a cool, dry place for up to 12 months.