Few people think of the shell bean as an exciting food to grow. After all, beans are probably the cheapest source of protein available. So why go to all the effort of growing and shelling beans?
I grow shell beans for the same reason I grow salad greens: the opportunity to experience a wider palate of tastes, textures and appearances than you’d ever find in a supermarket. When you grow your own shell beans, you aren’t limited to the productivity-oriented varieties industrial farms favor. If you can pick your beans and eat them within hours, rather than the weeks it takes for commercial beans to be processed, they’ll taste better and retain more nutrients.
Beans also improve the soil in which they grow because of their symbiotic relationship with soil bacteria. Finally, there’s the cultural connection. The world of shell beans is tangled up in the history of humanity. Many varieties have been passed down from generation to generation, leaving family legends of Grandma’s shell bean or Uncle Roy’s lima. The names of strains reflect colorful histories: ‘Black Turtle,’ ‘Bohemian,’ ‘Old Timer,’ ‘Ozark Razorback.’ And who could resist grinning when eating a bean called ‘Greasy Grits’?
Types of Shell Beans
Lima beans (Phaseolus lunatus) typically have half-moon-shaped pods with flat, gently rounded beans inside. Most cultivars grow vines, so they’ll need a support system. ‘Fordhook Giant’ is probably the best-known and most widely grown vining lima bean. It thrives throughout the United States, and produces generous yields of large beans. Another variety that grows well is ‘Dixie Speckled Butterpea.’ When you split open its modest green pods, you’ll be amazed to find that the beans are brightly speckled in burgundy and cream. The color is destroyed by cooking, but the look of the raw beans is so spectacular that you’ll treasure them for looks alone. There are also a few bush-type limas. ‘Henderson’s Bush Lima’ is an heirloom variety that grows no more than 18 inches high and yields well even in poor conditions. Its beans are the typical light green lima color.
Runner beans (Phaseolus coccinea) are more prominent in British gardens than American ones. Their big furry pods are often picked when young and tender, and used as green beans. At maturity, the pods swell with the huge beans held inside. The individual beans are amazing — a sort of bent lozenge shape, more than an inch and a half long, and colored hot pink with heavy burgundy speckling.
Soup beans (Phaseolus vulgaris) are the most diverse of the shell bean types. They are “green beans” allowed to grow to maturity. As such, they come in a fascinating variety of colors, sizes and shapes.
Many types of shell beans produce well given moderate temperatures and moisture, and then decline in long periods of intense heat and humidity. Not so with cowpeas (Vigna unguiculata). When the mercury hits 90 — and stays there for weeks — cowpeas will laugh. Give them torrid nights and steamier days, and they’ll flourish. Some cowpeas bush and others vine, but most do a little of both. The vining types are stocky and multi-branching, while bush varieties tend to ramble. ‘Penny Rile’ is probably the heaviest yielding variety I’ve encountered. Its golden-brown pods (the color of aged paper) contain khaki beans that darken as they age. Another of my favorite cowpeas is the African heirloom ‘Haricot Rouge de Burkina-Faso.’ It’s a fabulous variety, with heavy yields of glossy purple pods. Split open the pods to reveal deep red beans.
As with any new crop, try small amounts of several varieties of shell beans from different groups to find out which grow best in your garden.
Growing Shell Beans
Shell beans are incredibly easy to grow. All you need is a sunny spot with good drainage. Shell beans are not particular about soil type, and they fix their own nitrogen through a symbiotic relationship with soil bacteria. In fact, extra nitrogen from an external source may discourage the bacteria and prompt excess growth at the expense of fruit and flowering.
Shell beans can be grown as a low-trouble cover crop. Just sow the beans in spring, keep them free of weeds, and let them grow wild through the summer. When autumn comes and the bean plants turn yellow, chop off the plants at ground level, thresh out the pods and beans, then chop up the remnants of the top growth and use the remnants to mulch the area. Cowpeas work particularly well as a cover crop because their thick growth smothers anything that tries to grow around them.
Beans germinate poorly in cold soils, so don’t plant them until the ground warms to 50 degrees or so, about the time of the last spring frost, when daytime temperatures are regularly in the 70s. (To determine your last spring frost date, see Garden Planning: It’s All About When.) Runner beans are the most cold-tolerant, and cowpeas require the most warmth.
Beans seeds are large, so this is one crop your three-year-old can help plant. Pole bean seeds should be planted about 1 inch deep and 2 to 3 inches apart. The spacing of rows will depend on your supports and the eventual size of the plant. Limas and soup beans are usually not so vigorous, although their ultimate size depends on variety and growing conditions. Generally, a 4-foot trellis will be ample. Generally, cowpeas are bushy and wide. Although they may only reach 4 feet in height, cowpeas branch heavily and will require 2 to 3 feet between rows. Runner beans are equally vigorous, but they tend to put more effort into vertical growth with less branching — so a trellis 5 feet high would not be too large. Bush varieties of all beans should be planted 3 inches apart. Rows should be 18 to 24 inches apart.
Two to three weeks after your beans germinate — when they’ve developed a set of true leaves and are beginning to look like real plants rather than seedlings — it will be time to thin them. Thinning means pulling out at least half of the seedlings. It may sound heartless, but it’s vital. Otherwise, you’ll have many scrawny plants growing into each other, which has an unfortunate impact on yield and ease of harvesting. Thin pole beans to 4 inches, and thin bush plants to 6 inches apart.
Having thinned your bean seedlings, there’s little to do but wait for them to shoot up and bring forth an abundant harvest. Make sure they receive at least an inch of water per week. If they don’t receive that much rainfall, give them a good soaking. Pole beans may need to be tied to their support systems. Check the bottoms of bush beans to make sure the beans are not lying in the mud. (If they are, harvest them as soon as possible and eat them fresh.)
Harvesting Shell Beans
You can begin harvesting fresh shell beans as soon as the pods start to swell up and you can see the beans bulging through. Limas and runner beans are particularly nice while still young. It’s fairly easy to see when the beans inside are developed enough to eat. If you like, you can harvest some of the pods off your plants for fresh beans and leave the rest to dry out for later. Cowpeas and most soup beans take longer to reach a size worth eating. Wait until their pods have turned golden and started to shrivel before harvesting. Then, you can easily twist the beans out of their brittle pods.