How to Grow and Care For Edamame

Originating from Asia, edamame or soybean is a versatile cropping plant that produces pods that can be steamed and shelled for tender fresh beans. It is a name given to the young beans while soybean refers to the mature beans. 

It is not a common crop, but it has gained popularity in North America in recent times. These crops yield a sweet, nutty, creamy flavor and contain abundant protein.

They are low-maintenance, similar to bush beans but often with a higher yield. These crops help fix nitrogen in the soil, making the soil more nutrient-rich for later crops. The soybean plants are frost tender and need a long hot summer to crop well, therefore only suited to being grown outdoors in milder regions.

Edamame is a frost-tender vegetable planted in late spring in a location with full bright sun and average soil fertility. Avoid planting edamame where legumes were grown in the previous season, thus preventing the continuation of disease and pests. 

Since these tender soybeans are easier to cultivate than you think, you need to explore the ideal time to sow these nitrogen-fixing legumes, how to choose the perfect location, and the best practices for spacing and planting depth. 

When To Plant Edamame Seeds

Edamame requires a growing season of 10 to 12 weeks, depending on the variety. You can directly sow seeds during the late spring safely after your last spring frost when the soil is warmed to at least more than 55°F.

Don't rush it to plant in cold wet soil, otherwise, these seeds will rot in no time. Stagger sowing times with each plant pod handily maturing all at the same time. For the second harvest, plant the seeds about ten days later after the harvesting time.

Where To Plant Edamame Seeds

Beans grow best in full sun for at least six hours, but edamame can handle some tight shade. These beans can grow in average soil fertility, offering the same soil health benefits. It aids in fixing the nitrogen in this soil, making it nutrient-rich for later crops. 

Don't plant it where the legumes were grown during the previous season, preventing the depletion of nutrients in the soil and pests and diseases. 

How To Plant Edamame 

These plants grow best when air and soil temperatures reach at least 60 to 70 degrees Fahrenheit, without any risks of frost. Here is how you can plant edamame seeds:

• First, sow seeds one-fourth to half an inch deep, 2 to 4 inches apart, in rows 2 feet apart, that receive full sun. 
• Germination of seeds takes 1 to 2 weeks

Growing edamame is easy as these plants are very low-maintenance and have growing needs similar to bush beans. You can directly seed, without needing to fuss with indoor seed starting, and the productive plants yield a heavy crop of fuzzy pods. 

Plant edamame in late spring in a garden bed offering full sunlight exposure, at least 6 hours every day. They grow fine in soils with average fertility. Avoid high-nitrogen fertilizers, which promote lush leafy growth but can impact pod production. 

Another thing is to treat the seeds with a natural soybean inoculant to encourage their growth, thicker root formation, and higher yields. 

Here is how you can help edamame to grow properly:

• Harden off your young edamame plants for a week or two before moving them outdoors.
• Plant them once frost passes in a well-drained yet moist sunny position about 15 cm apart. 
• Thin seedlings to 6 inches apart when the plant is 4 inches tall
• Weed shallowly to avoid disturbing the plant's roots
• Apply compost, leaves, or hay mulch to control weeds and retain the soil moisture
• Make sure to water regularly even though edamame tolerates some drought, but yields may suffer
• They do not need staking as these plants reach 1 to 3 feet tall like bush beans.

Growing Edamame From Seeds

You can leave your edamame beans on the plant to ripen into soybeans. During the summer, when the plant's leaves begin to drop, harvest the ripe yellowish pods, and store them in a dry airtight container.

It is easier to grow edamame from seed. Like bush beans, they are a frost-tender vegetable and can't be planted until the soil is warmed to at least 65 F. Planting in cold wet soil can cause seeds to rot.

Lay a sheet of black or clear plastic on top of the bed leaving it for 7-10 days and remove it when you are ready to sow the seeds. After the growing conditions become right, sow seeds by planting them 1 to 1 or half inches deep and 3 inches apart.

Thin the seedlings 4 to 6 inches once they grow well. To prolong the harvest, consider planting a second crop 3 to 4 weeks after the initial planting.

Sowing Soybeans Indoors

From mid to late spring, sow seeds 5cm deep into individual 8cm pots or deep root trainer pots filled with moist potting compost. Place in a propagator, or cover with polythene and stand in a warmer place at a temperature of 20°C.

Once the seedlings appear, move to a heated greenhouse, and ensure the compost stays moist. Harden off the seedlings to gradually acclimatize to outdoors before planting out after the frost risk is gone.

Sowing Soybeans Outdoors

Ideally for outdoors, warm the soil before sowing seed directly by placing clothes, fleece, or clear polythene over the ground for at least 2 weeks. 

Sow from late spring to mid-summer, placing 2 to 3 seeds together, 5 cm deep and 15 cm apart. Once the seedlings grow, thin if needed to leave one seedling, selecting the strongest ones to retain.

If space is created, make several sowing over a couple of months to harvest over a longer period. 

It's time to harvest the edamame when the pods grow 2 to 3 inches long, plump, and bright green. If their color changes to yellow, it shows that you have waited too long. The yellow pods and or leaves indicate the peak of the flavor and texture has passed away.

Harvest the ripe pods every day or two throughout 2 to 3 weeks but don't pull the pods from the plants, but snap them with your fingers. Harvest the dry soybeans when the plant and leaves are dry and brown and the seeds inside the pods rattle.

Pull up the plants and hang them in a dark, dry area until the pods are completely dry. 

How To Store Edamame

Edamame purchased fresh is preferably eaten the same day as the flavor starts to degrade as few as 10 hours after the harvest. However, fresh edamame will stay edible to eat for three days, if stored in a refrigerator.

Freezing fresh edamame is another option for maintaining good quality over a few months and should be blanched first, before being frozen. 

Here are certain tips on how to store the edamame;

• Store fresh edamame in an airtight container or plastic bag in a freezer for a week. 
• To freeze edamame pods or shelled beans, blanch them, plunge them in ice water, and then drain. Store in an airtight bag in the freezer. 
• Store dried beans in an airtight container in a dark, cool, and dry location.

To care for edamame, a regular supply of water is crucial. During the dry conditions, water thoroughly 2-3 times a week. Mulching the soil around the roots with well-rotted compost helps the soil retain its moisture. 

These plants are easy to care for and require only a few basic maintenance techniques including:

• Maintain Slightly Acidic Soil

Edamame thrives best with soil maintaining a pH value, of 6.0, which is slightly acidic. You can use compost manure to keep a rich soil filled with nutrients. However, as a green bean, these plants can fix their nitrogen, they might not be the use of fertilizers until it is necessary. 

• Thin Your Plants

When the plants reach around four inches in height, thin the superfluous leaves until the plants are distanced six inches apart, to prevent them from overcrowding. 

• Weed Carefully

Edamame plants have delicate roots, so be aware while weeding to prevent them from any damage. 

• Watering

Edamame plants should be watered throughout the season, even after their blooming. Keep the soil moist but not overwatered. A regular water supply is needed for fruit-producing crops like edamame. During warmer weather conditions, watering should be done 2-3 times a week.

• Light And Temperature

Edamame thrives under the sun as it needs at least 6 hours of direct sunlight for optimal growth. These warm-season legumes prefer sunshine over shade. 

As for temperature, these plants are happy in moderate to warm weather conditions. The ideal temperatures range from 68°F to 77°F but can tolerate slightly cooler or warmer spells.

Therefore, plant them when spring glows and nighttime temperature stays consistently above freezing temperature. 

Poor growth of edamame is commonly caused by low temperatures and sometimes due to lack of water. Ensure the crop is getting watered during dry spells in moderate amounts and spray organic mulch to hold moisture in the soil.

Check whether the soil temperature is warm enough (at least 18°C or 64°F) and plant seeds at the correct depth.

Poor growth of edamame is commonly caused by low temperatures and sometimes due to lack of water. Ensure the crop is getting watered during dry spells in moderate amounts and spray organic mulch to hold moisture in the soil. 

Pests like Aphids stink bugs, and grasshoppers adore munching on edamame leaves and pods. You row covers or use organic pesticides to prevent them from entering. These crops may face fungal diseases like downy mildew and bacterial diseases, which can damage your crop.

Also, the lack of nitrogen, essential for legume growth, can be solved by inoculating seeds with nitrogen-fixing bacteria before planting. 

Management Strategies

Irrigation may be necessary for growing edamame, during times of increased water demand, such as flowering and pod-fill stage. Most herbicides are not eligible for edamame, so growers rely on mechanical and hand cultivation for weed control.

The plant may not face any enemies in the form of diseases but if the plant is harvested while green, it avoids many late-season problems. Pets that can attack include soybean aphids, stink bugs, and leafhoppers.

The best way to deal with these pests is to select more pest-resistant varieties. Also, the diseases can be managed by using fungicides, choosing resistant varieties, and practicing crop rotation. 

There are several varieties of edamame available, each resembling its unique characteristics, some are noted below:

1. Agate 

Agate is a classical and widely grown edamame variety, which matures in about 55-60 days. This type produces small, olive-green pods with two or three large, sweet beans. It is known for its good disease resistance and is considered reliable for home gardeners. 

2. Black Jet

The black jet is another famous edamame variety, which matures in about 60-65 days. They have a slightly sweeter flavor than Agate and are a good choice for stir-fries and salads. This type produces large, dark purple pods containing two to three large, meaty beans. 

3. Envy

Envy is a high-yielding type that matures in about 60 days like the black jet. It produces large, light green pods containing 2 to 3 large beans, which boast a sweet and nutty flavor, good for snacking. 

4. Early Hakucho

This edamame type is a compact plant and an early maturing variety, which can be harvested in 50-55 days. It is a good choice for short seasoning gardens and produces medium-sized, green pods with 2 to 3 beans. 

5. Shirofumi

Shirofumi is a high-yield type of edamame with over 100 pods per plant. It is a late-maturing variety that takes about 70 days to mature. It possess a mild flavor and is a good choice for soups and stews.