Rising soybeans: Edamame from scratch

What do you think of when you think of soy? Large agricultural fields full of bushy plants or maybe you think of soy milk or tofu. Anyway, if you haven't thought about growing your own soybeans, then exploring soybean growing can inspire you to start growing your own soybean crop.

Some claim that soybeans are the world's oldest food crop, which is not surprising when you consider that soybeans are more than a source of food. Then there is edamame, the unripe green soybeans popular in Asian cuisine. If you have not yet eaten edamame, you are missing out on a tasty meal or snack and once you've tried it, you'll want to grow your own.

Soybeans are easy to grow and care for because they don't require much special attention and they are similar (although not the same) to other bean crops. This guide will detail exactly what to do, from planting to harvesting soybeans, so that you can nibble on your own edamame at the end of the growing season.

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Brief instructions for care

Let's discuss how to grow soybeans! Source: UDel Carvel REC

Common name (s) Soybean, edamame, soybean
Scientific name Glycine max
Days to harvest 45-65 days for fresh harvest
Bright Full sun
water 1 inch per week
floor Well permeable
fertilizer Aged compost midsummer
Pests Aphids, Mexican bean beetle
Diseases Fungal and bacterial rot

Everything about soybeans

Commercial soybean fieldA commercial soybean field can be huge. Source: UnitedSoybeanBoard

Soybean plants were discovered around 1100 BC. Born by Chinese farmers in Southeast Asia. A colonist brought the first seeds to America in 1765. Common names are soybean, edamame, and soybean. The botanical name is Glycine max Glykys means sweet in Latin.

Soybeans are a high source of natural fiber and protein. The edible part is the bean, which is first cooked or steamed before consumption. Beans are also made into candles, detergents, plastics, and hair care products, to name a few. The soybean is an ideal catch crop for reducing weeds and adding organic matter to your soil.

If you haven't seen these popular beans growing in a farmer's field, you may not be sure what this herbaceous annual looks like. It is an upright bush that can grow up to 5 feet tall, although most average 2-3 feet tall. Each plant can produce more than 100 pods that grow to 1.5 to 3 inches long.

A pod grows from self-fertilizing purple or white flowers that rise from stem knots. Each stem has three individual oval leaves at the end. Pods arise from each flower and grow in clusters of two or three. The seeds in the hairy pod can be green, brown, or yellow, with 1 to 4 seeds per pod.

The soybean plant life cycle has eight phases (depending on when you harvest the bean). These include seed, germination, seedling, growing plant, flower, small pod, large pod, and ripe pod. In the next few sections we will discuss how to grow, care, harvest, and store your soybeans.

Plant soybeans

Soybean seeds are best planted directly in the garden bed in early spring, as soon as the soil temperature is 60 ° C. These beans are not frost tolerant, but you can plant soybeans in warmer regions in late winter as the planting times are different. Sow soybean seeds 1-1.5 inches deep and place them about 10 inches apart. Place your rows 2 feet apart to leave room for the bushy plants.

As long as they get plenty of sunlight, warmth, and space, you can plant soybean seeds in a raised or in-ground garden bed. Be careful not to over water the soybean seeds as they will rot easily.

If you live in a cold climate with a short growing season, plant soybeans indoors 6 to 8 weeks before your last frost date. Transplant young plants outside as the soil warms up, keeping them 4 to 6 inches apart. If soybeans are planted too late in the season (even in early summer) it will affect plant size and soybean yields. However, you can choose varieties of soybeans that ripen earlier.

If you don't have the space, grow the soybean seeds in a container at least 12 inches deep. This offers a lot of space for stable roots. Monitor the soil moisture in the pot as it dries out faster compared to garden soil.


Soybean rootsSoybean roots develop nitrogen-fixing nodules. Source: UnitedSoybeanBoard

Let's examine specific care tips for growing soybeans so that your plants will thrive from the time you planted them to the time you harvest the crop. Fortunately, soybean plants grow well when they meet all of the basic growing conditions.

Sun and temperature

Plant soybeans in full sun (8 hours of sunlight per day), otherwise partial shade areas will prevent your soybeans from ripening and affect the soybean yield. Soybeans grow in USDA growing zones 2-11, so choose a soybean variety that will thrive in your climate.

The best growth is seen at temperatures between 70 ° F and 95 ° F. If the weather is too hot or too cold, these legumes won't thrive. They are not frost hardy and damage occurs at temperatures below freezing.

Water and moisture

After planting and until the seeds germinate, keep the soil moist, but do not pour over it. Soybeans can tolerate a bit of moisture as long as they don't get too hot, e.g. B. Temperatures above 95 ° F. Once the plants are in the major vegetative stage, plan to water at a rate of 1 inch per week.

Water at the base of the plant in the morning to keep the foliage and flowers dry. As flowers begin to form, increase the amount of water to 1.5 inches per week, and then when small pods begin to form increase further to 1.75 inches per week. Soy tubing or drip irrigation work well with soy.

These beans are not drought tolerant, so it is best to have an irrigation schedule for the growing season. Stop watering as soon as the pods fill up and you notice that some of the leaves and pods are turning yellow.


Soybeans grow well in neutral to slightly acidic soils with a pH range of 6-6.8. They can tolerate poor soils, but for best results, plant them in well-drained clay soil with organic mulch to keep weeds at bay and prevent the soil from drying out. Loamy soil has an even amount of clay, silt, and sand. It drains well and holds the right amount of moisture.


While the soybeans ripen, there is no need to add nitrogen fertilizer to the soil. Since soybeans are a legume, they perform what is known as nitrogen fixation. They enter into a symbiosis with nitrogen-fixing bacteria in the soil in order to convert atmospheric nitrogen into usable nitrogen. The plant, in turn, supplies the bacteria with carbon. Otherwise, soybeans are not heavy feed, so an aged compost applied in midsummer will provide a lot of nutrients until harvest.


The type of soybean you grow in the garden will determine how tall and bushy the plant will be. Most soybeans grown in home gardens reach 2 feet in height and do not require pruning. If the plant becomes overgrown and takes up space for other plants in your garden, you can prune back the invader.


As mentioned in the planting section, the best way to propagate soybeans is to sow them 1-1.5 inches deep directly into the garden once the soil temperature has warmed to 60 ° F. Usually in late spring when the air temperature is at least 70 ° F. Do not soak or douse seeds before germination has occurred.

Harvest and storage

SoybeansDried soybeans can be planted or stored for later cooking. Source: matsuyuki

This next section covers harvesting soybeans and how to store them fresh and / or dry. We're going to look at other methods of saving so that you can find the one that works best for you.


The timing of the soybean harvest depends on whether you want edamame (the green pods) or dry soybeans. The pods usually ripen at the same time, so you can pick them all at once. Edamame (the unripe soybean) is ready when the pods are 2 to 3 inches tall, light, and plump. For this type of harvest, simply pluck the pods from the plant.

Ripe pods (for dried soybeans) are still not ready for harvest for 2-3 months; give them a total growth time of more than 100 days. The leaves of the plant will turn yellow and the pods will turn brown, indicating that they are ready to be harvested. Now you can pull out the whole bush and hang it upside down to allow the beans to dry further. Once dry, pluck the pods from the plant and remove the beans from the pods. After harvesting, throw any remaining plants in the compost


Fresh soybeans keep well in the refrigerator for about 7-10 days. Place peeled or unpeeled soybeans in a well-sealed container. Raw soybeans should never be eaten raw as they are not easily digested. Cooking makes them ready for human consumption.

You can freeze unripe soybeans (edamame); either with the pods or just the fresh beans. Bring a saucepan of water to a boil, add a pinch of salt and cook the edamame for 3 minutes. Soak in ice water to stop cooking, drain, then towel dry. Put in a freezer bag and freeze immediately. Frozen beans can be kept for up to a year.

Another option is to dry the unripe soybeans for a healthy, crispy snack. Boil the peeled beans in water for 7 minutes. After cooling, brush with salt and olive oil. Place on a baking sheet and bake in the oven at 200 degrees for 6 hours. Alternatively, you can simply dry edamame in a dehydrator. Store dried edamame in an airtight container for 2-3 months.

Peel dried ripe soybeans and place in an airtight container. You can store them in a cool, dry place for 1-2 years. They will last longer if kept at a constant temperature of 50-60 degrees Fahrenheit.


Tops of soybean plantsThe tops of soybean plants in a commercial area. Source: UnitedSoybeanBoard

If you grow soybeans on a small scale in the home garden, you will not encounter as many pests and diseases as you would if you were a commercial farmer. However, there are some general concerns worth mentioning.

Growing problems

The biggest growing concern is Germinate your soybeans. Most gardeners will overwater the seeds, causing them to rot from too much moisture. Water enough to moisten the soil, but don't let the soil become saturated after planting.

Another concern is Pods fall from the plantwhat happens when the plant is stressed. A few pods here and there aren't a problem, but if you see several falling off, you need to step in. Mostly it is related to over- or underwatering, too much heat or too little heat.

Soybeans planted in sunny spots in the garden will do well if the Temperature is not extreme. If you live in areas with extreme heat, your soybeans will do better in partial shade.


Common pests that attack soybeans are bean beetles and aphids.

Mexican bean beetles are a pest that affects the legume family. They are related to the ladybug, but larger and pale yellow. If left on the plants, they will eat leaves, pods and stems. Pick the beetles from the plants and remove yellow clusters of eggs from the underside of the leaves. Diatomaceous earth that is spread around the base of the soybean plant can help prevent infestation.

Aphids are a common pest that happily attack a wide variety of vegetables. They are tiny, oval shaped, and can be light green, tan, yellow, or dark brown. Damage from these pests can kill your plant and you will see decreased growth, speckled and / or curled leaves. Sprinkle them off the plants with water or use organic insecticidal soap. Encourage ladybugs to come into your garden to keep the aphid population down as well.


Soybeans are prone to fungal infections like Root rot, mildew, and Cercospora leaf rot. Some form of root rot can cause sudden death syndrome, which has become a major problem with soybeans. Prevention is the best way to reduce the chance that these will affect your plants. Soybean plants need a lot of space that allows air to circulate. Also, water from the soil and make sure your garden has well-drained soil.

Another concern is Bacterial rot, this is an air and water sickness that enters through all wounds of the plant. Affected plants have yellow and brown leaves, preventing the plant from absorbing water and nutrients. The rot will continue to spread quickly to the rest of your crop. Prevention is also important.

Use a crop rotation and keep pest infestation to a minimum. In the early stages, cut off damaged leaves and stems with clean tools and apply fungicide to prevent further spread. If the damage is severe, it is best to remove the entire plant before it spreads to others. Organic fungicides are most effective for prevention, not treatment.

frequently asked Questions

Soybeans dry on the vineSoybeans dry on their vines in the sun. Source: Stephen Downes

Q: How long does it take to grow a soybean?

A: When soybeans are grown for their fresh pods, it takes 45 to 65 days for them to ripen. However, if you want dry beans, they will take at least 100 days.

Q: Is it easy to grow soybeans?

A: Yes, they are easy to grow as long as you have temperatures above 70 ° F for at least 45 days. After planting, they need warmth, sun, and moderate moisture. They don't need a large amount of nutrients as they are nitrogen fixers.

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