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Black Soybeans

Soybeans are a fall staple — a cozy addition to your kitchen and garden as the weather cools. Black soybeans, a lesser-known variety, are a great twist on your favorite bean recipes.

Black soybeans on a table.

If you’re unfamiliar with black soybeans, or soybeans in general, we’ll tell you what you need to know. Keep reading to learn about black soybeans, the best ways to enjoy them, and even how to grow them in your garden.

History of the Black Soybean

Although commonly associated with Japanese cuisine, it’s believed that soybeans may have originated in China around 1000 BCE, making them the oldest known soy food worldwide. The first documented reference to black soybeans in the western world is in the nineteenth century.

Now, they are particularly common in Japan and the Philippines.


Characteristics of Black Soybeans

Soybean plants usually grow to about two feet high and boast ample foliage. The soybeans grow in pods, which are broad, hairy, and flattened, and grow to around 3 inches long. When they mature, they turn yellow or brown in color.

Black soybeans are an inexpensive source of plant-based protein. Easy to grow and even easier to cook, black soybeans are usually prepared dried and reconstituted in water or pre-cooked in cans. They are smaller than yellow soybeans, and though both have the same inside yellow color, these are black on the outside.

Roasted black soybeans revealing yellow interiors.

Eating Them

What do they taste like and what do they pair well with?

Black soybeans are actually more similar in flavor to black beans than to yellow or other soybean varieties. They have a delicate skin and soft texture that require slightly different preparation than other types of soybeans.

They work well in recipes that call for black, navy, and pinto beans.

How to Use in Cooking

Beans are a tasty and filling addition to any recipe. Bean soup, chili, and bean salads are classic meals for using black soybeans.

Pro tip: Before consuming, let the black soybeans sit in salt water overnight to avoid a mushy texture.

Bowl of cooked black soybeans.

Recipes

This Times Food soybeans falafel recipe recommends combining the beans with spring onion, parsley, bread slices, and coriander leaves, and then serving with hummus or mayonnaise.

Or, you can serve these Betty Crocker soybeans with rice. Good Life Eats has a Fall Mexican Rice Bowl recipe, with chicken, rice, salsa, and avocado that you can add black soybeans to for an extra-hearty dinner.

There’s also a traditional Korean dish that puts black soybeans at the center: Braised Black Soybeans, or Kongjaban. We especially like this recipe from Crazy Korean Cooking.

For those who prefer sweet to savory, Chopsticks Chronicles provides a traditional Japanese recipe for Kuromame, or Sweetened Black Beans. This new year’s treat is made by soaking the beans in sugar and soy sauce for a dessert-like finish.

Koean black bean noodles.

Health Benefits

Black soybeans are very healthy. They support heart health, repair oxidative damage, may reduce the risk of certain cancers, and promote bone health. They are high in carbohydrates, fiber, vitamins, protein, minerals, and antioxidants.

Soy is also known to alleviate hot flashes and depression as well as improve skin health and kidney function.


Growing In Your Garden

Soybeans are incredibly space-efficient plants, growing between 25 and 40 pods per plant. This makes them a popular choice for home gardens.

Growing From Seeds

Black soybeans can be grown from seeds. Plant seeds 1 to 2 inches in depth, with no more than 6 seeds per foot. Rows should be about 1 to 2 feet apart.

Soybean plants in a field.

Water, Soil, Sun

This plant’s seeds thrive in a soil temperature no colder than 60 degrees and no warmer than 85 degrees. While soybeans can be grown indoors in zones that are outside these temperature ranges, it’s generally not recommended.

They require a pH level in the 6.0 – 6.8 range. Warm, well-drained soils yield the best results. You can add mulch to the soil to lock in moisture so that you don’t feel the need to overwater, which can damage flowers or pods. Overwatering makes the plant more to disease and lowers pod yield.

Use inoculants to increase yields when natural Rhizobia populations are low. Rhizobia is a kind of soil bacteria that helps fix nitrogen to the soil, which helps soybeans grow. Soybean inoculant is used to add rhizobia to the soil.

If you’re adding bacteria to soil, be sure to avoid using a fertilizer that is too high in nitrogen. Nitrogen is beneficial, but remember that it’s possible to have too much of a good thing!

After harvest, nitrogen remains in the soil, so having an excess will disrupt future nitrogen fixation processes. A fertilizer favoring phosphorous and potassium, like Dr. Joe Tomato and Vegetable Bubble from Hoss, which has a high potassium quantity relative to nitrogen, works well.

Full sun is ideal, but partial shade is tolerable too. If you grow in partial shade, you’re likely to have a smaller harvest.

Closeup of soybean pods.

Pests and Diseases to Watch out For

Aphids and leafhoppers are the most common pests you’ll encounter with black soybeans. Aphids can be washed off with a strong stream of water. Check for leafhoppers if the leaves begin to curl and after storms if you keep your plants outside.

Other common pests include:

  • armyworms
  • blister beetles
  • corn earworms
  • crickets
  • cucumber beetles
  • deer
  • flea beetles
  • gophers
  • grasshoppers
  • Japanese beetles
  • Mexican bean beetles
  • nematodes
  • rabbits
  • stink bugs
  • tarnished plant bugs
  • woodchucks
  • wireworms

Common diseases include root rot and white mold. Both are caused by cool, damp conditions and can be prevented by spacing plants well and not handling the plants while wet. Common soybean diseases include Anthracnose, Bacterial blight, Bean common mosaic virus, Damping-off, Fusarium wilt, Leaf spot, Powdery mildew, and Rust.


When to Harvest

Dried black soybeans.

You’ll know it’s time to harvest your beans when they become round within their pods and the leaves change color from bright green to a more yellow tone. Pick the brightest green pods that have more than two beans within them.

They are ready to harvest after 50 to 90 days.

Storage

Fresh soybeans pods, which are green, will stay fresh for up to a week in your refrigerator. Dried, shelled beans can be stored for 10 months to a year in a dry, cool space.

Will my soybeans come back next year?

Black soybeans grow on an annual cycle, so you will need to sow seeds again the following year.


Where To Buy Seeds

Soybean seedlings in a garden.
Soybean seedlings.

You can buy black soybeans from most major supermarket chains, including Whole Foods, Trader Joe’s, and Target. If you are looking to plant your own, True Leaf Market sells organic black soybean sprouting seeds by the pound at about 175 seeds per ounce.


Grow Your Own Black Soybeans Today!

Soybean pods on a plant.

Now that you know how to grow and cook with black soybeans, be sure to check out our Beans, Peas, and Lentils page for our blog posts on beans and other soybean varieties!