HIGH STAKE GREEN BEANS
On the modern factory farm, nothing could be as outdated as the idea of growing green beans on poles. What efficient farmer can afford to set up acres of trellises, then hire workers to pick them again and again? On the farm, bush beans are king. Plant them, and 60 days later run the automatic bean picker down the rows. Then pull the plants out and start over. For the most part, that's exactly how it goes. But in Florida there are still winter vegetable growers who plant acres of pole beans to send north to market. And in Oregon as recently as the early '70s, all beans grown commercially for processing were pole beans. Even today, American seedsmen send a million pounds and more of Kentucky Wonder pole bean seed to Japan, where it's the number one choice of vegetable farmers.
The reason pole beans manage to hold out despite the odds in commercial bean culture is simple: taste and texture. As good as regular bush beans are, nobody has come up with a bush bean variety that has all the good eating qualities of a pole bean. Virtually everyone who has grown both - including the top bush bean breeders - will tell you pole beans are their favorites for flavor. Bush beans are not without their followers, however. In 1845 when H.D. Thoreau set out to make his little patch of borrowed earth say beans, he chose a bush variety to do the job. And so it is that the gardening world today breaks down into two camps: confirmed bush bean growers and confirmed pole bean growers. At the heart of the matter is the same thing that pushes most vegetable farmers toward bush beans: the trellis. Bush beans are easier to tend, and they are indisputably delicious. That's good enough for a lot of people. Flavor superiority aside for the moment, pole beans offer a couple of advantages that may surprise dyed-in-the-wool bush bean fanciers. in small gardens, pole beans are the real space saver. What pumps out beans isn't so much the number of plants as the leaf area exposed to sunlight. Ten row-feet of pole beans growing up a seven-foot trellis have about the same leaf area as 30 feet of bush beans. And that 10 feet of pole beans will yield its crop at a pace much more in tune with a family's needs. Bush beans produce their entire crop at once. Typically, the heaviest wave comes first, ripening over three or four days, with a lighter flush coming on a week to 10 days later. After that, it's time to pull out the plot. To keep the beans coming all summer you have to plan successive sowings. With pole beans, the crop ripens steadily and last's all season, right up until frost. You pick every three or four days. Don't get me wrong - I'm not trying to convert confirmed bush bean growers. For some, there is a place for bush beans. Maybe a trellis seems impossible, or you want a basket or two of beans all at once for freezing or canning. But for my money and trouble, the effort of setting up a trellis for pole beans is offset by the effort involved in making a second, third and fourth planting of bush beans that I need to keep me in beans all season.
Fistful of beans
Kentucky Wonder and Blue Lake run neck-and-neck as the best green bean varieties of all time. They've been around for a hundred years or more, yet still set the flavor standard among vegetable breeders today. More gardeners grow them than any other pole beans.
The name Kentucky Wonder first appeared in an 1887 Ferry seed catalog. The bean had come from a Kentucky resident named Nancy Davis, and it is likely that her bean was a strain of an older variety, perhaps one called Texas Pole that predates 1864. Kentucky Wonder makes vigorous vines that bear eight-inch pods, with a slight curve at the end. The young beans are tender and stringless but develop a tough string as the pods mature.
Blue Lake's origins are more obscure. The name seems to have been used first in Oregon in the early decades of this century, referring to a bean that had come from the lake district near Ukiah, California. According to Jim Baggett, a vegetable breeder at Oregon State University in Corvallis, who has more than one good bean to his credit, the Blue Lake pole bean is likely a selection of Striped Creaseback, which was first mentioned in print in 1822. Blue Lake's seven-inch pods are straight and stringless even when fully mature. Green beans are self-pollinating, making it easy for gardeners to save seed from year to year. There's no need to isolate varieties or pollinate by hand. It's in the nature of the bean for slight changes to appear spontaneously. Sometimes the astute home seed-saver notices this and favors seed from plants showing preferred characteristics. That's probably how Ms. Davis came to be especially proud of the bean she sent to the Ferry seed company a little over a hundred years ago and how Blue Lake came to be refined from the older Striped Creaseback.
This year's All-America Selections winner pole bean comes out of that same tradition of improvement, enhanced by a generous dose of the vegetable breeder's art. Kentucky Blue is the product of Kentucky Wonder crossed with a bush variety of Blue Lake. It's the work of Calvin Lamborn, the Idaho-based plant breeder who invented the Sugar Snap pea. It would be hard to imagine a pole bean with a more promising heritage. Lamborn was trying for a bean that would satisfy the vast Japanese appetite for American pole beans when he began this project about 12 years ago. Kentucky Wonder is the favorite, and Lamborn felt he could improve the old classic substantially if he could just straighten out the pod. (In the Japanese markets, green beans are sold in bundles tied together with string. The J-hook that Kentucky Wonder tends to develop at the tip results in a large percentage of beans that must be culled out, adding to the high cost of producing a pole bean.) In its first season in Japan, Kentucky Blue is already a hit among farmers. And with the AAS gold medal, it promises to score well with American gardeners, too. Its pods are much straighter than Kentucky Wonder and mature almost a week earlier, on vines that are slightly less rambling. The ideal stage for harvesting pods is about seven inches. The beans can reach 10 inches at maturity, but they develop a light string that will need to be removed. The flavor is excellent, very much like Kentucky Wonder with an intangible little something "extra" from the Blue Lake side. Rob Johnston, of Johnny's Selected Seeds in Albion, Maine, which features an above-average number of pole bean varieties, was very impressed with Kentucky Blue when he trialed it for the All-America judging several years ago. "The plant is beautiful. It really stands out in a trial row. The arrangement of the leaves on the vine is almost mathematical. There are enough leaves for good growth, but not too many. The pods are very visible and easy to pick. The pods are attractive too, a warm green and not real fuzzy as many beans are.
European plant breeders have developed different styles of pole beans that may also please American palates.
Fortex, developed at a French research station, produces an extremely long bean, up to 11 inches. Its selling point is that it's completely stringless, even when dry on the vine. That means you can harvest it at several stages for different eating preferences. Picked at six or seven inches, the beans are only half grown, providing the intense flavor and tender flesh of a filet bean, but in a much more convenient size. Or you can pick them at 10 to 11 inches, when the beans have formed inside, for a more hearty taste. Fortex is tender at all stages.
Northeaster is a European greenhouse pole bean with an American name that alludes to its 56-day ripening time. It produces as quickly as any bush variety. While it has the flat shape and buttery texture of a Romano-type bean, its flavor is sweeter, akin to the Blue Lake taste.
From the Pacific Northwest comes Cascade Giant, another long-podded bean that offers a wide harvest window. Introduced by Jim Baggett in 1990, this new pole bean is an improvement on the regional favorite, Oregon Giant. Cascade Giant has longer pods (11 inches) and is stringless and round rather than flat. The gray-green pods are streaked with bright purple, which vanishes during cooking. Seed will be available for sale in the spring of 1992.
The time to set up a trellis or poles is right before you plant. Bean seed sprouts fast and grows quickly. The young plants are brittle, so you don't want to be working around them, driving stakes and tying twine. As you plan your system, figure on a height between six and seven feet, or as high as you can comfortably reach for harvest and insect control. A six-foot row of pole beans is the minimum to provide a family of three or four with fresh beans about twice a week through the season. The most space-efficient system is a continuous-row trellis made of wire or nylon mesh hung on metal or wooden poles. The mesh should be about six inches square - big enough to get a fistful of beans through. Space the poles roughly six feet apart in the row, depending on the length of your trellis mesh. For firm anchoring, poles will need to be eight to nine feet long. Stout saplings, iron pipe or conduit are good choices. Anchor the poles by sinking them into the ground about two feet. The best method I've found is to drive the holes with a heavy steel digging bar, then firmly compact the earth around the poles with the tamping disc on the end of the bar. The teepees that are so often pictured in gardening texts are not a particularly good idea. They are very stable but not space efficient, and they make the beans hard to see at harvest. Pole beans are big plants, requiring ample space. Teepees have most of their space at the base where the beans don't grow. At the top, where the vines want to be, space gets very congested. You would pick more beans per pole if you set the poles a foot or so apart, with one plant per pole. If you have an abundance of tall poles too slender to support a mesh, setting them closely in the row, perhaps linking them with twine for the vines to branch out onto, is a good plan - and certainly better than a tripod. You want your plants to be six to eight inches apart. The safest procedure is to plant a seed every three or four inches in the row and then remove every other one a week after they sprout. If you get skips in the row, you can compensate by snipping the growing tip out of an adjacent plant as it starts to run. It will send out two runners in response, and you can train one to fill the gap on the mesh. Don't mix varieties in your planting or picking. Since different beans can have slightly different cooking times, it's likely some in the pot will be ready while others are still raw. Unlike soybeans and some other legumes, green beans are not powerful nitrogen fixers. Even with the help of soil inoculants, they'll need the same rich soil, well drained and high in organic matter, as any garden vegetable. Because they will crop for two months or more, they can use a midseason feeding of dilute liquid fertilizer. Just as important in sustaining a long harvest season is keeping the beans picked before they have a chance to mature seed. The younger you pick them, the more intense their beany flavor. However, many green bean aficionados also like the way they taste with half-formed beans inside. The young seed adds a different flavor and the texture of the pod becomes rich and slightly starchy. While it's this matter of flavor that pushes gardeners to the trouble of engineering a trellis each spring, then taking it down and storing it, the promise of an extended harvest is powerfully appealing, too. Succession planting gets tedious, after all. And there's something else. A trellis full of healthy beans is a handsome sight in the garden. Picking them from a comfortable standing position is a real pleasure. Gathering a mess for dinner - with the late afternoon sun backlighting the vines, with next week's harvest slender and small overhead, and above it nodding white blossoms - provides some of the finest moments in the garden I've known.
The only pest on green beans that's really difficult to control is the Mexican bean beetle. But in just the last 10 years a truly remarkable biocontrol for gardeners has emerged. Before the days of the Pedio wasp (Pediobius foveolatus), the Mexican bean beetle - which looks like a fat, coppery version of a ladybug - would reliably decimate any bean planting in its territory. It has been especially bad in the eastern half of the continent and south of New England. Despite the most diligent handpicking, the beetle would inevitably foster a population explosion that would reduce bean foliage to unproductive lace over the course of a month. And there's no insecticide - organic or not - that you want to spray on a crop you pick as often as beans. Bush beans were one of the best defenses: plant, pick, then destroy the plants, bugs and all.
The solution to the bean beetle problem began in 1969, when USDA scientists imported the tiny wasp Pediobius foveolatus from India. They learned that though It could not overwinter to become naturally established in the North America, they were able to raise it pretty easily in the laboratory. In Virginia, Maryland, Delaware and New jersey, USDA entomologists began to develop a practical program for large-scale control. Today, those four states regularly release the Pedio wasp in key areas where soybeans or snap beans are grown commercially. There, the bean beetle has essentially ceased to be a problem for farmers and gardeners. Working with cooperating farmers, the scientists establish 1/8-acre nurse plots of soybeans and snap beans mixed. When the first bean beetle eggs are spotted, they bring lab-reared Pedio wasps to the plots and egg parasitism begins. The female wasps deposit their eggs in the larvae of the Mexican bean beetle. In roughly 10 days, the larvae become paralyzed and die, and the new generation of wasp adults emerge. Soon the second generation of wasps spreads out into the surrounding countryside, hunting for more bean beetle larvae. Nurse plots are typically spaced every 100 to 200 acres, but the wasps can fly 20 miles or more. By the end of the season the MBB population becomes so low that treatment isn't needed again for at least three years. If the bean beetle is a chronic problem in your area, don't wait for a similar USDA program. Without commercial bean acreage nearby, the cost to taxpayers would be prohibitive. But you can easily purchase your own Pedio wasps. Since they'll take care of such a large area, work with neighbors to share the cost. Place your order by phone when you spot the first adults. Set the Pedio cases in the garden immediately. Adult wasps will begin hatching within days. Relax, enjoy your healthy bean vines and watch a dramatic biocontrol show at its best. You'll always have a few MBB around, but damage will be trivial. You'll soon see the mummified bodies of parasitized larvae all over, and from each body will come six to 12 more wasps. Occasionally, you may even spot the tiny predators combing your vines for orange larvae. For anyone who's had to yank brown, beetle-ravaged vines before their time, it's a satisfying sight indeed.
The spined soldier bug is another effective biocontrol. Order the soldier bug when you first spot the masses of yellow, oval eggs on leaf undersides; the nymphs you release in the garden will immediately begin preying on hatching bean beetles.
SOME LIKE IT HOT
In the Deep South, or wherever sweltering weather causes ordinary green bean blossoms to abort, you can stiff harvest bean pods through the long summer. Called dow guak in Chinese, and asparagus bean or yard long bean in English, this heat-loving legume (Vigna unguiculata sesquipedalis) is very close kin to the southern pea (a.k.a. black-eyed pea), and thus not a true green bean at all. But it has been bred for use as a green bean for centuries in parts of the orient, and it thrives when the weather turns subtropical.
"Yard long" is an unfortunate name for this bean, and it would be a shame if the horticultural hype led anyone to disappointment. The idea of a three foot bean is a bit daunting to those of us who can scarcely keep up with the bounty of regular-sized pole beans. Not to worry, the time to pick the pods is when they reach the diameter of a pencil and are 12 to 16 inches long. The pods are inedible at two feet, and more so at three. Yard long beans taste something like regular green beans, but have their own unique qualities. Some say the flavor is stronger. All agree that the beans are crisper, suiting them well to stir-fried dishes. When you want to serve them steamed and buttered, cook them longer to get them fully soft. If you like both regular green beans and southern peas, you are sure to like yard longs. Plant yard long beans two weeks after the last frost date. This is a bean that really doesn't come into its own without lots of heat. Space plants at least six inches apart and provide the same kind of support you would for any pole bean. The beans will do best if you treat the seed with a southern pea rhizobial inoculant at planting time. Some seed reportedly is contaminated with a mosaic virus. If you spot yellow mottled leaves, pull out and destroy the plants immediately. The beans will grow as far north as zone 6, but don't expect high yields or a long harvest season in cooler climates. If you really must try them, seek out seed for a quick maturing bush form of southern pea and harvest the immature pods for snap beans.