Soybean: Direct Sow Vegetable
How to Sow
- Because soybeans are members of the legume family of plants, they can benefit from an application of a soil inoculant designed for beans and peas, prior to planting. The inoculant will enable the plants to take nitrogen from the air to use as fertilizer, which can increase crop yield and quality.
- Sow in average soil in a sunny location after danger of frost and soil has warmed, from spring to midsummer.
- Sow in rows 18-30 inches apart, sow seeds 3 inches apart and cover with 2 inches of fine soil. Firm lightly and water gently.
- Seedlings emerge in 7-14 days.
- Thin gradually to stand 6 inches apart when seedlings are 1-2 inches high.
How to Grow
- In dry weather, keep soil well-watered. Plants need about 1 inch of rain per week during the growing season. Use a rain gauge to check to see if you need to add water. It’s best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
- Cultivate or mulch to keep weed-free, but do not work or handle plants when leaves are wet.
- Bean plants may stop producing beans at the hottest point of summer. When temperatures moderate, bean pods will again begin to develop.
Harvest and Preserving Tips
- Soybeans are a first-rate package of nutrients, one filled with protein, fiber, and an assortment of chemicals that help reduce cholesterol and may offset some cancers. They can be eaten at either the shell (half-mature) or dry stage, or as sprouts.
- For shell beans, pick when the pods are plump but still green and soft. Fresh soybeans lose their flavor quickly, so use them immediately after picking. Most pods ripen at the same rate, so you may want to pull the entire plant. Put pods in boiling water for several minutes to make shelling easier.
- For dry soybeans, harvest entire plants once their foliage has yellowed, and hang them upside down in a warm, airy place. (Soybean pods shatter easily, so don’t wait too long to pull plants.) Once the pods are entirely dry, shell and store soybean seeds in airtight containers in a cool location.
Common Disease Problems
Anthracnose: This is a fungus that causes brown sunken spots that enlarge into round black spots with pinkish centers. Seeds turn yellow with rusty brown spots. The disease spreads with slashing water and can overwinter in the soil. Burpee Recommends: Rotate crops with plants in a different family. Do not handle plants when wet. Do not compost infected plants.
Common Bean Mosaic Virus: This virus causes mottled yellowish foliage with leaves that curl downwards. The plants are stunted and yields are reduced. The disease can be spread by aphids. Burpee Recommends: Remove infected plants and discard. Control aphids. Grow resistant varieties.
Downy Mildew: This fungus causes whitish gray patches on the undersides and eventually both sides of the leaves. Burpee Recommends: Rotate crops with plants in a different family. Avoid overhead watering. Provide adequate air circulation, do not overcrowd plants. Do not work around plants when they are wet.
Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.
Root Rot: This fungus causes damping off in seedlings, and in older plants, the leaves turn yellow and drop off, stunting occurs, pods and seeds are small and roots are discolored. The fungus can live in the soil for five years. Burpee Recommends: Rotate crops with plants in a different family. Consider planting bush beans in containers.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Bean Beetle and Mexican Bean Beetle: The white larvae bore into roots and can also damage stems. The adult beetles are reddish orange, ¼ inches ling with 3-4 black spots on their backs. They chew holes in leaves from the underside. Mexican bean beetles look like copper colored lady bugs. Burpee Recommends: Hand pick. Remove plant debris. Check with your local Cooperative Extension Service for pesticide recommendations.
Cutworms: These insects cut off the seedlings at the soil level. Burpee Recommends: Place a paper cup collar (use a coffee cut with the bottom cut out) around the base of the plant. They are usually mostly a problem with young seedlings. You can also control by handpicking and controlling weeds, where they lay their eggs.
Leafhoppers: Leafhoppers cause injury to leaves and stunt growth. They also spread disease. Burpee Recommends: Remove plant debris. Use insecticidal soaps. Consult your Cooperative Extension Service for other insecticide recommendations.
Japanese Beetles: Burpee Recommends: Hand pick early in the morning into a bucket of soapy water.
Soybean FAQs
What are inoculants? Inoculants are dormant bacteria safe to use with beans. Beans, like peas, form a beneficial relationship with these bacteria commonly found in soil to capture nitrogen. Inoculants help beans planted in less than optimally warm or poor soils. New or heavily disturbed soils and soilless mixes need inoculants as they do not have a natural supply in the soil already.
Are your seed treated with inoculants or fungicides? We do not treat our seed with any products after harvest.
Why do I have no flowers on my plants? Too much fertilizer will make lots of leaves and no flowers OR
Pole beans take much longer to produce than bush beans. In the South, a pest called the Tarnish Plant Bug may inject a toxin into the plant that stops flower and pod production.
Why do my plants have flowers but no pods? Heat, moisture, and nutrient stress (usually phosphorus and calcium) can cause flowers to abort.
How do I make edamame? Lightly steam beans, add a hint of salt and enjoy as Edamame.