A Guide to Growing and Harvesting Edamame

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Edamame makes a healthy pick-your-own snack for kids.
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Fresh green soybeans have a buttery, nutty flavor.
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Edamame soybean plants closely resemble regular bush green beans.
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Author John Navazio picks a plateful of edamame for his taste tests.
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Edamame plants can set lots of pods for heavy yields.

Learn about growing and harvesting edamame in the garden.

The joys of edamame (or you can call them green soybeans).

It isn’t often we discover a truly new
crop for our vegetable gardens. Asians have been enjoying
edamame (“ed-ah-mah-may”), sometimes called “green
vegetable soybeans,” for many years. But this nutritious
and delicious crop is still unknown to most American
gardeners. As soon as you taste the sweet, nutty,
melt-in-your-mouth flavor of edamame, I predict you, too,
will become a devotee of this wholesome, easy-to-grow
vegetable.

Here’s what you need to know about growing and harvesting edamame. Edamame soybeans are different varieties than the types
grown as a dry field crop for making tofu, soybean oil or
other soy products. Edamame varieties are harvested while
they are still green, before the pods dry, much like
shelling peas. I first tried edamame at a Japanese
restaurant, where it was served as an appetizer in the
traditional style. The beans came to our table in a large
bowl, piping hot, looking exquisite in their emerald green
pods. I was with two Japanese friends, who taught me the
proper etiquette for eating edamame from the pod. They
showed me how to hold the pod lengthways near my lips and
then pinch the outer edge of the pod, pressing the beans
against the inner seam to split it so the beans popped
neatly into my mouth. Eating them from the shell in a
common bowl is a time-honored tradition that enhances the
pleasures of social interactions with friends. You can also
shell them before you serve them, or add them to stir-fry
or other dishes.

There’s another excellent reason to give edamame a try this
summer. Many of us are eating more soy foods than ever
before as we learn about the health benefits of this
nutritious food. Aside from being a great source of quality
protein and vitamin E, soy foods contain isoflavones, which
seem to play a role in reducing the risk of heart attack,
osteoporosis, breast cancer and prostate cancer.

Growing Edamame (Green Soybeans)

Edamame does well in many different soil types, but make
sure the spot is well drained with plenty of mature compost
worked in. Soybeans are a warm-season crop, so plant the
seeds when it’s time to transplant tomatoes, or when the
soil is at least 60 degrees. Sow eight to 10 seeds per foot
in the row, at a depth of 1 to 1 1/2 inches. Edamame plants
can get rather bushy, so space your rows at least 2 to 2
1/2 feet apart. All soybeans, including edamame, are
legumes that host beneficial nitrogen-fixing bacteria on
their roots. To take advantage of this natural nitrogen
production, you can dust your seeds before planting with a
bacterial inoculant for soybeans (available from most seed
catalogs that offer edamame.)

Some Japanese farmers transplant this valuable crop from
the greenhouse. To do this, be sure to grow the seedlings
in separate pots and carefully transplant them after
hardening off the plants.

Make sure your edamame bed gets full sun and give the
plants the same amount of water you give peas or beans.
Once the plants start yielding harvestable pods, keep the
beans picked on schedule, not missing any. Remember the
plant’s goal is to reproduce, and they won’t continue
yielding if you allow them to make seed.

When do you Pick Edamame?

Harvesting edamame pods for fresh eating is like picking
peas for shelling. The first sign your crop is close to
harvest is the swelling of the pods. Once this starts it’s
a good idea to check your plants every couple of days to
monitor their progress. This is important because they can
quickly over ripen and become starchy. When the beans are
fully formed and almost touching each other within the
pods, open a few of the plumpest pods to see if the beans
are fully formed, and taste a few of them raw. They should
be mildly sweet and tender without any starchiness.

Iowa gardener David Cavagnaro says, “There’s a very narrow
harvest window, and you really have to pay attention to get
the maximum tenderness and sweetness from your crop.” Never
let the pods turn yellow, a sure sign the beans inside are
getting starchy and past their prime.

Cooking or Freezing Your Edamame

So now you’ve got a crop of edamame coming in, and you’re
finding out just how many pods those couple of rows you
planted can produce. If there are more ripe pods than you
can use fresh, the best way to preserve them at their peak
of perfection is to freeze. Freezing edamame is almost as
easy as cooking them to eat on the spot. All you do is wash
them, then cook and freeze right in the pod.

For freezing, put the pods into lightly salted, boiling
water, and instead of cooking them for five to six minutes
as you would when you plan to eat them fresh, reduce the
cooking time to three to four minutes. When they’re done,
lift the pods from the boiling water and put them into a
basin of ice water. This will stop the cooking process.
Once all the pods are chilled, lift them from the water and
pat the excess water with a clean kitchen towel. Next place
them into plastic freezer bags, press the excess air out
and pop them into the freezer. When you want a taste of
summer, just take a bag out of the freezer, pour the
contents straight into a pot of boiling water and cook for
only two to three minutes.

Best Edamame Varieties for the Garden

To evaluate the edamame varieties now offered in seed
catalogs, I enlisted the help of two astute gardeners in
other parts of the country, gardener and photographer David
Cavagnaro in Decorah, Iowa, and C.R. Lawn, a seeds person
in Canaan, Maine, to augment my plantings in Bellingham,
Washington. Together we tested the same five varieties: two
stalwarts, “Envy” and “Butterbeans,” from Johnny’s Selected
Seeds in Albion, Maine; two Japanese newcomers to the
United States, “‘Sayamusume” and “Misono Green,” from
Territorial Seeds in Cottage Grove, Oregon; and the variety “Shirofumi” from Fedco Seeds in Waterville, Maine. The
three of us planted these five edamame varieties during the
last week of May in our respective locations, and we all
enjoyed enough warmth and sunshine to get our crops off to
a running start.

By the middle of August in Iowa and Maine, and early
September in Washington, we were all picking and grinning
as we discovered just how delicious homegrown edamame can
be. We all agreed a good edamame variety had to have a
sweet, buttery flavor with a tender, but slightly crunchy
texture. But there is another important attribute of good
flavor. C.R. Lawn summed it up best: “There’s a nutty
flavor that I look for in edamame. It’s the nuttiness that
gives body to the flavor.”

For earliness, there were two clear winners, “Envy” and
“Shirofumi.” For an early harvest, “Shirofurni” had the
sweetest, most tender beans; it got rave reviews in all
locations. But “Envy” shouldn’t be counted out. “Envy,”
which is touted as a first early variety, was easily 10
days earlier than “Shirofumi” for me in cool, coastal
Washington State. In the hotter summers of Iowa and Maine
(yes, Maine can have hot weather!), it wasn’t significantly
earlier than “Shirofurmi.” While “Envy” wasn’t as sweet as
other edamame varieties, it did have a robust, nutty
flavor, which coupled with its earliness should earn it a
spot in any short-season garden.

“Sayamusume” received the real honors for flavor. It took a
little longer to mature but was well worth the wait.
“Sayamusume” was about a week later in maturity than the
other varieties in Iowa and Maine. Another edamame
connoisseur, Steve Peters of Seeds of Change in Santa Fe,
New Mexico, says, “Sayamusume” is everything you want in
edamame: It’s plump, tender, sweet, with a buttery flavor,
and it’s consistent from pod to pod.”

David Cavagnaro recognizes another plus for gardeners who
“shell out” their edamame for cooking: “Both ‘Sayamusume’
and ‘Shirofumi’ have big pods with big seeds, which makes
then easier to shell than the other varieties

“Butterbeans” was the real surprise in this test. Since
“Butterbeans” is derived from a cross between an American
soybean and a Japanese edamarne, I suspected its flavor and
quality wouldn’t match the other purebred edamame
varieties. However, it did well in all locations, with a
harvest window just behind “Envy” and “Shirofumi,” and a
buttery, sweet flavor almost as good as “Shirofumi.”

“Misono Green” received less praise than the others, as its
flavor was on the bland side and it wasn’t early. It did,
however, yield well, setting quite a few pods.

Growing Edamames for Your Region

Regionally, there were differences in these varieties’
reaction to the environment. “Envy” and “Butterbeans”
seemed to perform best in more northerly locations, with
“Envy” showing its early advantage in the cool coastal
Washington summer. In trials performed in New Mexico by
Seeds of Change. “Envy” produced few harvestable pods and
had yellowing leaves on spindly plants. Jeff McCormick of
Garden Medicinals in Earlysville, Virginia, tried growing
“Butterbeans” a few years ago only to find an unappealing
discoloration of the beans in the green-shell stage.

Margaret Crow, a homesteader near Southwest Ranches,
Florida, plants her edamame in August or September for a
winter crop and has had great success with “Butterbeans,”
demonstrating how a variety from another region can work if
planted at the right time of year. However, she also grows
“Envy” under this regimen and its yields are still poor.

As always, the best advice is to grow at least a couple of
different varieties in your garden and scrutinize the
results. Obviously, a variety like “Sayamusume,” which
performed superbly in Maine, Iowa, Washington and New
Mexico, should do well in most locations.

When he’s not snacking on edamame, independent plant
breeder John Navazio trains seed growers and develops
improved vegetable varieties for organic growing at his new
company, SEEDS (Sustainable Education for the Ethical
Development of Seeds), in Iowa City, Iowa.


Edamame Seed sources

Johnny’s Selected Seeds
www.johnnyseeds.com; “Envy,” “Butterbeans”

Territorial Seed Co.
www.territorialseed.com; “Sayamusume,” “Misono Green”

Fedco*
www.fedcoseeds.com; “Shirofumi”

*Fedco is the only U.S. supplier of “Shirofumi,” but its deadline for 2002 orders has passed.

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