Soybeans: An Edible Cover Crop You Can Plant Now

By Brenda H. Reed

Freelance Writer

ood gardeners know that raising healthy plants depends upon how fertile and healthy their garden soil is. A cover crop will add significant amounts of organic matter to the soil. Cover crops yield a variety of long-term benefits for the home garden: increased amounts of organic matter improves the water holding capacity of soil, improves drainage in clay soils and provides a range of macro and micro nutrients that optimize plant health. Soils amended with organic materials such as tilled in cover crops, organic mulches and compost are so nutrient enriched that you will seldom, if ever, find a need for commercial fertilizers. Almost all cover crops grow better in the heat of spring and summer here in Texas, as well as in general.

Most cover crops grow very well here in Texas, but my favorite cover to grow is soybeans. They are a quick cover crop, taking only a few months in the late spring to summer garden. If my garden isn’t empty, and it very seldom is, I’ll plant soybeans in whatever section or row in the garden that is empty for a brief period of time. Personally, I am crazy about the immature beans (Edamame) I harvest from my soybean cover crops. (More about edamame later in this article.) Soybeans are a nitrogen-fixing legume. They associate with nitrogen-fixing bacteria to get their nitrogen from the air. This process involves a symbiotic relationship between leguminous plants and various strains of Rhizobium bacteria found in the soil. The bacteria actually infect the plant roots (in a good way), causing small nodules to grow. Within these nodules, the bacteria extract nitrogen from the air and fix it into forms the plants can use to make protein. In return, the bacteria receive sugars from the plant for their own nutrition. That is why farmers rotate soybeans with corn – to take advantage of this legume’s nitrogen-fixing ability.

The use of cover crops is an essential part of organic gardening. Not only do they enrich the soil, they cover and protect the soil from erosion. Organic matter is the lifeblood of garden soil, and cover crops add a lot of organic matter to soils. Cover crops are often called green manure crops. Till cover crops into the soil at least two weeks before the next crop of vegetables or flowers are to be planted. The soil organisms breaking down the cover crop can tie up available soil nitrogen. After breakdown is almost completed, the organisms start dying back and release nitrogen for soil usage. Normal watering is required for soybeans and they don’t require extra fertilizer if your garden soil is amended with plenty of organic matter.

Planting Soybeans

Remove all plants from the previous season. Soybeans like exposure to full sun. Till the soil. Make rows about 3 feet wide and a foot or two apart. You may also just broadcast the seed in a field or the entire garden without making rows. Plant the soybeans 3/4 inch deep, 4 inches apart. Cover the seeds and tamp the soil on top of them lightly to insure good soil contact. Water thoroughly. If the weather is dry, water the plantings every few days until the plants have emerged. Then, water as needed throughout the growth period. Here in the southeast part of Texas, I plant the soybeans in the spring about 2 or 3 weeks after the time I plant my green beans. I plant them in any space in the garden that I’m going to leave free of vegetable plantings.

Saving Seed For Next Season

You can let the seed pods that you want to save dry on the plants if it is dry weather, otherwise harvest the pods and put them in a netted bag or bags, such as those that you buy onions in, and hang the bags underneath a sheltered roof where it is dry. When the pods have all dried, hull the dried seeds and put them in jars or any airtight container and store them in a cool, dry, dark place until you are ready to use them.

When To Till Under

If you are using the soybeans strictly as a cover crop and not harvesting edamame or saving the seeds for the next planting, the soybeans should be pulled up and left lying in the garden to decompose as soon as the plants begin to form bean pods. Leave the plants in the garden area to decompose for about two weeks, then till them into the garden soil. If you want them to seed for harvest, let the pods appear plump and full and then pick the beans. Then, pull the plants up and proceed as stated above.

imagePests and Diseases

Soybeans are largely pest and disease resistant. If you have problems with stinkbugs and bean beetles, they can be controlled with the use of floating row covers or predatory insects: parasitic wasps, nematodes, and lacewings.

What Is Edamame?

Edamame is a specialty soybean harvested when their seed (bean) is immature. They are dark green in color. In general, the seed is harvested when the pods are 80 to 90 percent full. Edamame varieties are more tender and they cook faster than a field soybean. I suggest buying varieties of edamame if you plan on harvesting the soybeans. The seeds of edamame are rich in protein and are highly nutritious. Worldwide, it is a minor crop, but it is quite popular in East Asia. The use of these soybeans was first recorded around 200 B.C. It was used as a medicinal and still is in some places. Here in the U.S., edamame is known by many names. The most common is vegetable soybean, beer bean, green soybean, and several other names. The word ‘edamame’ means “beans on a branch.”

As a snack, and this is my favorite way to eat these delicious beans, the whole bean pods are boiled in salted water for about eight minutes, then given an ice water bath (blanched), and resalted. You then just squeeze the pods with your fingers and pop the beans right into your mouth. You may also use the soybeans (shelled) in soups, salads or stir-fried. In Japan they grind the soybeans into a paste with miso, which is used to form a thick broth. Pods are sold fresh on the stem over there. Here in the U.S., they are sometimes difficult to find and they are frozen for the market.

Harvesting Edamame

Edamame is ready for harvest when the pods appear full and green, but not left so long that the pods begin to turn yellow and dry. Pick the pods from the vines as you would pick lima beans. There are generally two or three beans in each pod. For the best quality, the timing of your harvest is quite important.

In the U.S., edamame has potential as an easier-to-grow, better tasting, and more nutritious substitute for lima beans. It’s a very good cover crop as well, so give this crop a try soon. I grow organically here and I have no problems with pests or diseases. Japanese classify soybeans as summer or fall types. Only a few are day-length sensitive fall types. Summer varieties are planted in the spring and harvested immature after 75-100 days, depending upon the variety planted. Fall varieties are planted in the early summer and take about 105 days or more to mature.

Nutritional Information

Per 1 cup serving of edamame: Percent Daily Value:

Calories 125.0

Protein 12.1

Carbohydrates 13.1

Fat 3.6

Ash 1.7

Calcium 9.3

Phosphorus 180.0

Iron 2.7

Sodium 5.0

Vitamin A 130.0

Vitamin C 40.0

Edamame is also rich in amino acid.

Dietary Fiber 14.0

Potassium 7.0

Also, edamame is a complete protein, containing all eight essential amino acids. Edamame is the only vegetable that offers a complete protein profile equal to both meat and eggs in its protein content. Edamame is also the richest dietary source of isoflavones. One-half cup of edamame contains 35mg. of isoflavones.


Beer Friend, Belles boy, Buker’s Favorite, Butterbeans (green), Envy (green), Gion and Green Lion, to mention only a few of the multitude of varieties to choose from. I planted the Beer Friend and Green Lion varieties last spring and they produced a bountiful harvest. Then, of course we pulled the plants up and let them lay for a few weeks and tilled them into the garden soil.


You should blanch and freeze edamame as soon as they are harvested. I shell some to be added to soups and salads throughout the winter, but you can just freeze them all right in the pods. Bring a pot of water to a boil, add the pods (or shelled soybeans) and boil for 4 or 5 minutes. Next, give them an ice water bath and drain. Pat them dry with a clean towel, and put them into freezer containers or bags and freeze.

Peaceful Valley Farm Supply

Garden Seed Shop

Evergreen Vegetable Seeds

Marinated Edamame Salad


2 tablespoons olive oil

1 tablespoon honey

2 tablespoons water

1 tablespoon Dijon mustard

1/4 cup fresh lemon juice

1/2 teaspoon minced garlic

1/4 cup white wine vinegar

1/8 teaspoon fresh ground black pepper

1/2 teaspoon grated lemon peel

Salt to taste

1/4 teaspoon basil

1/4 teaspoon marjoram

Mix all the above ingredients together with a wire whisk.

The salad

2 cups steamed green beans, cut in 1-inch lengths

2 cups blanched and shelled edamame beans

1 chopped scallion

1/2 cup chopped red bell pepper

1 stalk diced celery

2 tablespoons minced parsley

1 coarsely chopped cucumber

2 heads Belgian endive, torn into bite sized pieces

Gently toss the salad ingredients and pour the dressing on them. Enjoy with a nice, hot piece of garlic toast.

Herbed Corn and Edamame Succotash

1-1/2 cups frozen or fresh-shelled edamame

1 tablespoon canola oil

1/2 cup chopped red bell pepper

1/4 cup chopped onion

2 cloves garlic, minced

2 cups corn

3 tablespoons dry white wine

2 tablespoons rice vinegar

2 tablespoons chopped fresh parsley

2 tablespoons chopped fresh basil

1/2 teaspoon salt

Freshly ground pepper to taste

Bring a small pot of water to a boil. Add edamame and boil for five minutes. Drain well. Heat oil in a large nonstick skillet, over medium heat. Add bell pepper, onion and garlic; cook, stirring frequently until vegetables begin to soften, about 2 minutes. Stir in corn, wine and edamame; cook, stirring frequently, for 5 minutes. Remove from heat. Stir in vinegar, parsley, basil, salt and pepper. Serve immediately. (This dish is delicious topped with grilled shrimp, salmon or chicken).

Artichoke/Edamame Pasta

1 shallot, sliced thin

1 onion, diced

4 cloves garlic, minced

1/2 teaspoon each red chili flakes and

Italian seasoning blend

6 sun dried tomatoes, reconstituted with

1/3 cup boiling water

1/3 cup lemon juice

1/4 cup vegetable broth

2 12-oz. bags frozen artichoke hearts

2 cups fresh or frozen edamame

4 cups slightly undercooked pasta

1/2 cup water

3/4 cup Gruyere

1/4 cup Parmesan

Chopped parsley and toasted sesame seeds

or pine nuts for garnish

In a large saucepan, sweat the shallot and onion on medium-high heat for five minutes. Add the garlic, chili pepper and herbs and cook 1 minute longer. Add the sun dried tomatoes and their liquid, along with the vegetable broth and lemon juice. Cook for 2 minutes, add artichokes; cook for 5 minutes. Add edamame and cook for 1 minute. Add the pasta and water; cook for about 3 minutes. Add cheeses; stir until melted. Garnish with the garnish ingredients. Add chicken, salmon or shrimp if desired.

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