How to Plant and Grow Yard Long (Chinese Long) Beans

Vigna unguiculata subsp. sesquipedalis

The yard long bean (Vigna unguiculata subsp. sesquipedalis) is an annual legume grown primarily for its delicious, super long pods.

Also known as Chinese long beans, long-podded cowpeas. or asparagus beans, they’re an absolute delicacy and are more popular in Asia than in North America.

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Although the pods look like pole beans that got a little carried away, as a member of the Vigna genus, yard long beans are more closely related to cowpeas, including black-eyed peas and crowder peas.

In this guide, we’ll cover everything you need to know to produce a healthy harvest of gorgeous yard long beans.

Here’s what I’ll cover:

Grown from seed, in one season this plant can produce vines up to 12 feet long.

Since these legumes are indeterminate, like some types of tomatoes, they’ll just keep growing until killed back by frost in autumn.

Like many of their legume relatives, the vines bear compound leaves, each with three spade-shaped leaflets.

Ants are very attracted to this source of nectar so you may notice them on your plants harvesting this sweet treat, without doing any harm.

They may even protect yard long beans from other insects to keep this food source to themselves.

Making this a rather unusual garden crop, the edible pods are extremely long, ranging in length from 10 inches to up to three feet long, depending on the variety.

Pods can be dark or light green, purple, red, or a mottled mix of colors.

How to Sow

Yard long beans are a warm season crop, so wait to sow or transplant seedlings until all risk of frost has passed – usually one to two weeks after the last spring frost.

Before sowing consider applying inoculant to the seeds.

Cowpeas have a mutually symbiotic relationship with Bradyrhizobium sp. (Vigna) bacteria, which form nodules on the roots and help these plants fix nitrogen.

Exceed’s Garden Combination Superior Legume Inoculant contains the right microbe for this legume – as well as a mix of other beneficial bacteria to inoculate garden peas, common beans (Phaseolus vulgaris), favas, limas, and many more.

Exceed Legume Inoculant

You can purchase a one-and-a-half-ounce bag of Exceed Garden Combination Superior Legume Inoculant, enough to treat eight pounds of seeds, from High Mowing Seeds.

Learn more about using inoculants with legumes here.

Sowing Indoors

If you have a short growing season, you might want to start seeds indoors to get a jumpstart.

Plan to sow seeds around six weeks before your last average frost, and use four-inch pots.

However, there’s a caveat – it’s best to sow these seeds in biodegradable pots rather than plastic ones to minimize root disturbance during transplanting.

I like to use biodegradable CowPots, made from composted cow manure.

CowPots 4-Inch Biodegradable Pots

You can pick up some CowPots in a variety of package sizes from Arbico Organics.

Fill the pots to within an inch of the rim with moisture-retentive seed starting mix.

Inoculate seeds by placing them in a small bowl, adding enough water to wet the seeds, then sprinkling a pinch of inoculant.

Next, poke a two-inch deep hole in the middle of each pot, and insert a single seed. Close up the hole over the seed, and pat the soil down gently.

Keep the growing medium moist but not soggy, and give the seedlings plenty of light – use a grow light if you need to.

Transplanting

About a week after your average first frost is past and when the seedlings have at least two true leaves, start hardening them off ahead of transplanting.

When the seedlings are hardened off, you can transplant them into the soil.

To transplant, first use a trowel or hori hori to make a hole in your garden bed big enough to accommodate the compostable pot.

Water in, and keep moist as the newly transplanted seedlings become established.

Space your transplants six to 12 inches apart.

Direct Sowing

To direct sow, wait until one to two weeks after your last average spring frost.

Wet the soil down ahead of time to prepare for planting, and inoculate seeds as indicated above.

Poke holes in the soil two inches deep, six to 12 inches apart, then drop a seed in each hole.

Squeeze the hole shut over the seeds, pat the soil down to ensure good contact, then water in gently with the shower setting on a watering wand.

Keep the soil moist but not soggy as seeds germinate – which should take six to 12 days – and young plants become established.

How to Grow

Yard long beans love heat and don’t like cold. If you’ve had issues in your area with varieties of P. vulgaris getting wimpy during heat waves, this species may be a good substitute.

Support

Before sowing seeds or transplanting seedlings, make sure a trellis is in place to allow for vertical growth.

The trellis should be at least seven feet tall to accommodate the vigorous vines.

Light

When deciding where to situate your beans, make sure you have full sun conditions – that means six to eight hours of direct sunlight per day.

Soil

Yard long beans will grow in a wide range of well-draining soil types, including clay and sandy loam. The soil should have a pH range of 5.5 to 7.5.

Want to learn more about what type of soil you have? You may want to do a soil test!

Water

Yard long beans require about one inch of water every seven to 10 days – though of course, that quantity will vary depending on the amount of sun, heat, and wind in your area.

Aim to keep the soil evenly moist but be careful not to let it become waterlogged.

If you need to irrigate, water at the base of plants rather than from overhead to reduce the risk of fungal diseases.

Mulch

Apply a thin layer of mulch around your yard long bean plants to suppress weeds and help to prevent moisture from evaporating.

Cultivars to Select

You may be surprised that for a vegetable that’s not so well known in North America, there are in fact many different varieties of yard long beans to choose from.

Here’s a sampling of some of the best cultivars:

Mosaic

‘Mosaic’ features pods that have a mottled purple, red, and green pattern.

Harvest when pods are still slim and reach 10 to 12 inches long – in approximately 70 to 90 days.

‘Mosaic’

You can find ‘Mosaic’ seeds in an assortment of packet sizes at True Leaf Market.

Orient Wonder

‘Orient Wonder’ produces smooth, dark green pods with excellent taste and texture.

Although these ones can reach 30 inches long, harvest pods in 80 days when they are 12 to 18 inches long for best eating quality.

‘Orient Wonder’

You can find ‘Orient Wonder’ seeds in packets of 20 from Botanical Interests.

Purple Mart Tsu In

Interested in bringing some color to your garden crops? Try the dark purple pods of ‘Purple Mart Tsu In.’

This variety produces tender, stringless, 20-inch pods in 75 to 80 days.

Unlike purple colored varieties of P. vulgaris that turn green when cooked, these pods turn from purple to black with cooking!

‘Purple Mart Tsu In’

You’ll find ‘Purple Mart Tsu In’ seeds in a variety of packet sizes at True Leaf Market.

Yu Long Noodle Kin

‘Yu Long Noodle Kin’ is an early maturing variety that produces dark green pods in just 65 to 75 days. The pods reach up to 30 inches long.

‘Yu Long Noodle Kin’

You can find ‘Yu Long Noodle Kin’ seeds in a variety of packet sizes available from True Leaf Market.

Managing Pests and Disease

Whenever you grow vegetables, there’s always the chance that some insect will decide to make a meal out of your crop or that certain conditions will conspire to cause the plants to contract a disease.

Read on to know what to be on the lookout for and how to prevent these problems.

Herbivores

Rabbits and deer will happily make a meal of your yard long beans before you have a chance to harvest. The best way to deter these herbivores is to use fencing to exclude them.

Learn more about building a DIY deer-proof fence here.

Insects

Pests are numerous in the garden, but when you grow companion plants to attract beneficial insects, your chances of them doing much damage will decrease dramatically.

Predatory and parasitoid wasps, for instance, do an amazing job at keeping pest populations in check. And this crop gets extra protection from ants, as discussed earlier in the article.

Here are a few pests to look out for:

Aphids

Aphids are common garden pests that tend to congregate on the undersides of leaves. Their feeding causes stippling on the foliage and large infestations may stunt growth.

You can use a strong jet of water from your garden hose to blast them off. Repeat daily for about a week – that may be all you need!

Learn more about controlling aphids here.

Cutworms

Cutworms are larval moths that hang out in the soil during the day, emerging at night to chew through the tender stems of young seedlings.

Our guide to dealing with cutworms has more information.

Thrips

Have you noticed silver or bronze speckles on the foliage of your yard long bean plants, as well as black specks? Thrips are probably at work.

They generally don’t cause too much harm, but if you have a large infestation, check out our guide to controlling thrips to learn more.

Disease

Here’s what you’ll need to know about disease and yard long beans:

Damping Off

Damping off is a fungal disease that causes seedlings to collapse.

The pathogens tend to strike during damp, cool conditions, so be sure to sow seeds or transplant after the weather has warmed up.

Learn more about damping off here.

Mosaic Viruses

Recognizable by the yellow, mosaic-like patterns on plant foliage, both Bean Common Mosaic Virus (BCMV) and Cucumber Mosaic Virus (CMV) can affect yard long beans.

Then make sure to clean any garden tools used while handling diseased foliage to prevent spread.

Powdery Mildew

Powdery mildew is a fungal disease that makes crops look like they have been dusted with flour.

This disease occurs when conditions are humid but mild.

To prevent high humidity levels among your crops, follow spacing recommendations so that there is adequate air flow between plants.

And remember to water at the soil level instead of from overhead.

Learn more about powdery mildew here.

Harvesting

Harvesting yard long bean pods regularly is key to keeping the plants producing.

To know when to check them for readiness, refer to the recommended mature pod length on your seed packet.

When pods are the right length, try snapping one in half. If it snaps cleanly, it’s ready.

To remove pods from the vine, hold the stem and then pull.

If you’re not going to cook the yard long beans right away, you can rinse them off and store them in the fridge wrapped in a paper towel in an open plastic bag for up to five days.

Preserving

You can preserve your yard long bean harvest by freezing, canning, fermenting, and dehydrating.

To freeze, start by cleaning the pods, and snapping off the stems and ends if needed. Cut them into one- or two-inch lengths, then blanch in boiling water for three minutes.

Remove the beans from the boiling water and plunge them directly into an icy water bath, drain, then set the pods in a freezer-safe container in the freezer.

Be sure to note the date on the container – the pods will be good for six to 12 months.

To can these veggies you’ll need a pressure canner.

It’s important to follow a trusted recipe when canning non-acidic foods due to the risk of botulism.

You can find tips for pressure canning produce at our sister site, Foodal.

To dehydrate, clean the pods and cut them into bite sized lengths. Either sprinkle with herbs and salt before drying them in a dehydrator or oven, or keep them plain.

Learn more about dehydrating garden produce here.

Recipes and Cooking Ideas

Yard long beans can be used very much like haricot verts. They are gorgeous when cooked quite simply – sauteed and flavored with nothing more than a little salt.

Looking for something that packs more of a flavor punch?

Substitute yard long beans in this spicy recipe for sriracha tofu stir-fry with green beans and carrots – you’ll find it on our sister site, Foodal.

Or if something cool sounds more appetizing, why not try this recipe for fried tofu and charred green bean salad, also from Foodal.

Looking for a savory side dish that’s delicious enough to enjoy as a palate-pleasing meal in itself?

Use a handful of your yard long beans in this recipe for Italian style green beans coated in olive oil, garlic, and tomatoes – it’s also on Foodal.

Your Supersized Green Bean Alternative 

It doesn’t get much better than yard long beans, folks: they’re generously sized and delicious.

And if this crop is new to your culture, you’ll surprise your friends and family when you serve them up at the dinner table in their superlong glory!

Do you have a favorite variety of yard long bean you’d like to tell our other readers about? Let us know in the comments section below.

Want to keep reading about growing beans in your garden? We have more knowledge for you right here: