- Soybean: Origin and Properties
- The Best Soybean Varieties
- Growing soybean plants in the garden
- The right care
- Harvest Soybeans
- Are soybeans he althy?
- Use of soy
- Is soy toxic?
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If you want to enjoy fresh edamame and homemade tofu, you can grow soy yourself. We give tips on choosing a variety, sowing and harvesting soybeans in your own garden.
The soybean (Glycine max) can be used in many ways and can be grown in your own garden or on the balcony. With us you will learn everything about planting, care and use of soy.
Soybean: Origin and Properties
The soybean originally comes from northern China and Japan and is the most important protein and oil crop in the world in terms of acreage. It belongs to the family Fabaceae and is closely related to pea (Pisum sativum), lentil (Lens culinaris), lupine ( Lupinus) and bean (Phaseolus vulgaris). Depending on the variety and conditions, soybean plants reach a height of 40 to 100 cm. The very hairy annual plants form a deep taproot. Like most legumes, soy lives in symbiosis with underground, nodular root bacteria. These soy-specific nodule bacteria (Bradyrhizobium japonicum) settle in round lumps on the roots and collect nitrogen from the soil air. The bacteria exchange this oxygen with the sugar that is produced during the photosynthesis of the soybean plant. In this way, they contribute significantly to the fertilization of the plant.
Soybean leaves are pinnate in three parts and, like the stems, very hairy. The self-pollinating, white or soft purple small flower appears between May and July during the soybean flowering period. After fertilization, elongated, brown hairy pods each containing two to three oval-round seeds form. Young, unripe harvested seeds including the pod are called edamame. The word comes from Japanese and means something like "bean on a branch". Between September and October - when the seeds are ripe - the entire soybean plant gradually dies off. The dry pods eventually burst open, releasing the seeds and scattering them around. Soybean seeds can be off-white, tan, brown, green, black, or piebald, mottled, or marbled.
The Best Soybean Varieties
All soybean varieties can be harvested for both edamame and dry beans. The only decisive factor for cultivation in Central Europe is early ripening. Early soybean varieties ripen 75 - 100 days after sowing between August and September, late ones only in October. With the latter, there is a risk that the soybeans will not ripen at all in cool and rainy summers. Therefore, only very early to early varieties are recommended for soybean cultivation in Germany.
- 'Agate': Very early soybean with fawn to dark brown seeds. The small plants bear plenty and can be harvested after 90 days.
- 'Chiba Green': Tasty edamame soybean with a very short development time. Harvesting is possible as early as 75 - 90 days after sowing.
- ‘Envy‘: Soybean up to 80 cm high with shiny green kernels. The immature pods can be harvested from August, the dry seeds from the end of September to October.
- ‘Fiskeby V‘: Very early, light yellow soybean variety for crunchy and sweet-tasting edamame. Harvest starts in August and dry beans in October.
- 'Green Shell': Early and stable edamame soybean with a short development time of around 100 days. The harvest extends from mid-August to the end of October.
- 'Hokkaido Black': Vigorous and bushy soybean variety with shiny black seeds adapted to cooler climates. They are served alongside Edamame as a dessert Kuromame during the Japanese New Year celebrations.
Growing soybean plants in the garden
The ideal location for soybean cultivation is sunny on quickly warming, permeable and well water-storing soil. The pH should be between 6.5 and 7. Outdoor sowing of soybeans can be done from a soil temperature of over 10 °C, which is usually reached between April and mid-May. Since soya needs a lot of time to ripen, it should always be sown before June. A preculture on the window sill from April with planting in May is also possible. The sowing depth is 3 - 4 cm, because soybeans are strictly dark germs. The distance between plants should be 10-15 cm, between rows 30-50 cm. At temperatures of 12 - 20 °C, germination takes about 10 - 20 days.
If you want to grow soybeans on the balcony or generally cultivate them in a planter, you shouldselect a pot with a capacity of at least 5 liters and good drainage. Fill the pot with high-quality potting soil such as our Plantura organic universal soil and then sow soy seeds in it. Three to four soybean plants can be cultivated in a 5L pot.
Tip: Our peat-free, compost-rich and sustainably produced potting soil in Germany is not only suitable for growing soybeans in pots, but also for improving soil that is too heavy or too sandy .
For particularly good growth and high yields, we recommend inoculating the soybeans with their natural symbiotic partners, the nitrogen-binding nodule bacteria, before sowing. The microorganisms are available as an aqueous solution together with a sugar-rich adhesive mixture in small quantities for hobby gardeners. Sugar and nodule bacteria are mixed in a spray bottle and then applied to the soybeans. The inoculated soybean seeds should now be planted quickly, as the bacteria are extremely sensitive to light and die off quickly when exposed to sunlight.
Soybeans are good preceding crops as they add nitrogen to the soil. After them, highly consuming vegetables such as tomato (Solanum lycopersicum) or zucchini (Cucurbita pepo subsp. pepo convar . giromontiina) can be grown. Soybeans themselves should only be planted in the same location every three years.
Summary: Grow Soy Yourself
- Ideal location: Warm and sunny on well-drained, water-retaining soil.
- For optimal growth: Spray the soybean seeds with nodule bacteria shortly before sowing.
- Sow from April on the window sill or directly outdoors from a soil temperature of 10 °C until the end of May at the latest.
- Sowing depth: 3 - 4 cm, planting distance: 10 - 15 cm, distance between rows: 30 - 50 cm.
- Germination takes place after 10 - 20 days at temperatures of 12 - 20 °C.
- In the case of pre-cultivation, plant from mid-May in beds or tubs in high-quality potting soil.
- Crop rotation: only plant soybeans every 3 years at the same location.
The right care
Soybeans require little care after germination. Fertilization is not necessary if enough nodule bacteria have settled on the roots. The water supply plays an important role until a sufficiently large root system has developed.Additional watering in the bed may therefore be necessary, especially when the soybean blossoms between June and August. Another care measure at the beginning is the removal of weeds until the soybean plants have formed a dense stand. A mulch layer of grass clippings and other materials reduces evaporation and can prevent the growth of unwanted weeds. At the same time, it provides food for soil organisms and thus promotes the formation of humus.
Common pests on soybean: Diseases and pests on soybean have so far only rarely occurred in Central Europe. However, the caterpillars of the painted lady (Vanessa cardui) can occur in nests on soybean plants, for example, and cause severe feeding damage. Pigeons and crows like to dig up freshly planted seeds and young seedlings. Young soybean sprouts are also a welcome snack for rabbits, hares and deer. A protective, fine-meshed net over the stock provides a remedy.
Harvest Soybeans
The harvest stage for green soybeans as edamame is roughly comparable to that of tender green bush beans. The pods should still be completely green and not lignified or fibrous, but the kernels on the inside should already be clearly visible. For most strains, edamame starts harvesting around 80-100 days after sowing. Would you like to harvest dry soybeans to make your own herbal drinks or tofu? Then you should wait until the entire soybean plant has turned brown. Depending on the variety, this is the case between September and the end of October. Ideally, the dry pods on the plant will rustle when touched, which is a sure sign of the start of the soybean harvest season. It is best to harvest in the morning when the pods are still damp and tough from the dew. This is because dry, ripe pods tend to burst open when harvested. The entire plant is cut off at the bottom with secateurs and left to dry in a sunny, warm place for a few days. Then the seeds are gutted by hand or threshed in a sack.
Are soybeans he althy?
Soybeans are he althy yet filling seeds. 100 grams contain about 150 kcal. Particularly nourishing ingredients of soy are the abundant proteins and fats. The very high protein content of soybeans of 30 - 50% is in the humanand animal nutrition can be used. When dry, soybeans also contain a certain amount of oil, between 18 - 24%. The high content of unsaturated fatty acids in soybeans is extremely he althy. In addition, the seeds contain various minerals and vitamins, especially vitamin E, potassium, calcium and magnesium.
Use of soy
Soy is playing an increasingly important role in human nutrition. Numerous meat and milk substitutes for vegetarian and vegan diets are mainly made from soy. In Asian countries, the use of soybean oil for frying and frying is common. Tofu and soy mince can be made from the seeds. However, soybeans also function as a he althy snack when roasted and processed. Fermented soybeans, as soy sauce or in the Japanese dish natto are particularly easy to digest. The young, still green and juicy kernels including the pods are boiled briefly as edamame and then served with s alt and other spices.
Tip: Incidentally, the so-called "soy sprouts" are not sprouts from soybeans, but from mung beans (Vigna radiata).
Is soy toxic?
In its raw state, young soybeans, mature seeds and all green parts of the plant are poisonous and can cause nausea and vomiting if consumed in excess. This applies to humans and pets, with the exception of rabbits. Both edamame and the dry soybeans should therefore only be enjoyed after sufficient cooking time or roasting.
The chickpea (Cicer arietinum), like the soybean, belongs to the papillae family and can also be grown on the balcony and in the garden. We give tips on choosing a variety, planting and care.