All about beans
Beans are a staple in nearly every garden. They are also an incredibly diverse group of plants. The bean family (Fabaceae) contains more than 20,000 species. Edible beans include chickpeas, lentils, peas, “true beans”, limas, favas, pintos, soybeans, cowpeas, yard-long beans, and others. They come in many shapes, sizes, and colors. While Iowa is known for growing soybeans, there are many other types of beans that grow well in the home garden.
Growing Beans
Beans are relatively easy to grow. All insist on sunny sites with well-drained soils. Most are warm season vegetables that are planted after the danger of frost has passed. Seeds are typically sown directly in the garden in rows 1.5 to 2 feet apart, approximately 1 inch deep.
Within a couple of weeks after planting, seedlings should be thinned to their appropriate spacing of 2 to 3 inches apart for best yield. While many species of beans will fix nitrogen – thus requiring less fertilizer once established, young seedlings do benefit from light fertilizer prior to or at planting.
Beans like snap and lima, are available in 3 different habits: bush, pole, and half-runner beans. Bush beans are compact, rarely reaching more than 2-3 feet tall. Pole beans are vining plants that often exceed 5-6 feet tall. Half-runner beans are in between, normally reaching 3-4 feet tall. Pole beans will require sturdy supports at least 6 feet tall. Half-runner beans perform best with smaller supports or trellising. Bush beans do not require supports or trellises.
Below are a few of the beans that can be grown in Iowa. Some perform better than others, depending on site and environmental conditions.
Snap beans (Phaseolus) are also called “green beans” or “string beans”. These are one of the easiest beans to grown in the home garden. They are normally available in bush, pole beans, and half-runner habits. While pole beans are more productive per square foot, supports are required for easier harvest. Snap bean pods may be green, yellow (often called wax), or purple. Varieties can produce round or flat pods. Snap beans produce beans quickly and continue to be productive if harvested frequently. Gardeners often stagger sowings of snap beans from mid-May to early-August for extended harvests. The purple podded snap beans will turn green when cooked. Unlike many other types of beans, snap beans are harvested and eaten pod and all, when immature, before the seeds bulge in the pod. (Days to harvest 50-60 for bush types; 60-90 for pole types)
Dry beans (Phaseolus) are also easy to grow in Iowa. Dry beans require more time to harvest as the pods need to dry completely before harvesting. When the pods are dry and rattle a little when shaken, the bean seeds inside are mature and ready to harvest. Dry beans are available in a wide range of colors including black, brown, red, white, and speckled. Kidney beans, navy beans, pinto beans, cannellini beans, and black beans are types of dry beans. Dry beans are easy to store for long periods in sealed jars indoors. (Days to harvest 70-110)
Lima beans (Phaseolus) are often more difficult to grow in northern parts of Iowa. Lima beans require longer periods of warm weather to be most productive. Bush and pole cultivars of lima beans are available. Seeds are shelled from the pods as soon as they are starting to bulge in the pods but are still green. As a dry bean, harvest after the pods are dry but before they split open. (Days to harvest 60-80)
Edamame (Glycine) are immature soybeans and they grow well in Iowa. Plants are approximately 3 feet tall and do not require support. Sometimes seeds are inoculated with Rhizobium to help plants establish quickly and improve yield. Pods are harvested when the seeds are plump and bulging in the green pods. (Days to harvest 80-100)
Yard long beans (Vigna) are sometimes called asparagus beans. Yard long beans require longer growing periods than common snap beans, but they often produce pods that are 2 feet long. Pods develop on vining plants that can exceed 8-10 feet, thus trellises/teepees will be needed for support. Pods can be harvested immature and used like snap beans when they are fully extended but before the seeds expand or plump in the pods. Or they can be harvested as a shell bean when the beans are plump in the pods but still green. (Days to harvest 60-90)
Fava or broad beans (Vicia) require cooler temperatures for best growth and development, this means they are not ideal for much of Iowa. When daily temperatures exceed 80°F, plants develop fewer pods and seed. Gardeners wanting to try fava beans should sow seeds in early spring so that plants grow and set seed before the onset of summer heat. Beans are harvested when pods are green but the seeds are plump and bulging in the pods. (days to harvest 80-100)
Southern peas or cowpeas (Vigna) are more like beans than peas as they are grown and harvested much like common beans. There are three common types of southern peas: black-eyed pea, cream pea, and crowder pea. They are available in bush and pole habits. Plants require longer periods of warm weather to perform best. The pods can be harvested immature with green, plump pods or fully dried. Sometimes cowpeas are planted as a summer cover crop to protect and improve soils. (Days to harvest 70-100)
Ornamental beans like Hyacinth bean (Lablab) and Scarlet runner bean (Phaseolus) are grown primarily for their attractive flowers. While the pods are edible (requiring cooking first), they can also be attractive and are often left on the plants as ornaments. Both hyacinth bean and scarlet runner bean are vines that require support to fully appreciate the flowers and pods.
This is a small sampling of the beans that can be grown successfully in the Midwest, including Iowa. Beans are not only highly productive garden plants, they are also highly nutritious. Try one or two new types of beans in your garden. You might be surprised at the ease of which many will grow in the home garden and surprised by the taste!
Other articles for more information on beans:
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 15, 2022. The information contained within may not be the most current and accurate depending on when it is accessed.