Beans are one of man's earliest cultivated crops, and were instrumental in allowing for non-nomadic living situations and thus the domestication of animals and the improvement of tools and implements. You could say that beans played an integral part in altering the course of human history and the development of many cultures around the world.
There are over 5,000 varieties of beans. For every pole bean there is a bush bean with numerous colors and shapes. Because beans readily cross with each other, the possible varieties are endless!
Most of the common garden beans (genus Phaseolus), regardless of shape, color, or size, belong to the same species (vulgaris), and therefore will readily cross with one another under the right conditions. The 'lima' or 'butterbean' represents a separate species, lunatus, and the species coccineus is the 'scarlet runner bean.' If we add to this the genus Vicia for the 'fava' or 'broad beans,' and the genus Vigna for the beans that are also often referred to as peas ('cowpeas,' 'asparagus beans'), we cover the most popular beans that are grown by the home gardener.
A 'pole bean' is one that climbs and requires some form of support,and a 'bush bean' tends to be short and bushy. A 'runner bean' tends to be bush-like with multiple 4'-7' runners. All types can also be a 'snap bean' (eaten as a green pod), a 'shelling bean' (the green seeds are cooked like fresh peas), or a 'dry bean' (harvested when pods are dry with seeds soaked and cooked like navy beans).
Much like a homegrown tomato, garden beans have a much richer flavor than those sold at the grocery store, and are well worth growing.
Most beans, except as noted, are very frost sensitive and should not be sown until the soil temperature is about 65 degrees F. Beans grow best when it's warm, but if the day temperatures are consistently above 85-90 degrees F, they may drop their flowers. Gardeners in the SW and South should plant mid-March for June harvest, and early August for a late September harvest.
The soil needs to be rich in organic matter, well drained, loose, and warm. Plant beans in ridges to increase drainage if the soil is heavy. Mulching is recommended to preserve soil moisture.
Watering is important, as the plant must be kept evenly moist, but not soggy. Water the soil, not the foliage, and avoid gardening in your bean patch when plants are wet from rain or morning dew.
Give your beans full sun, good air circulation and nitrogen fertilizer. They are legumes and produce their own nitrogen.
Snap beans are ready to pick when the pod "snaps" or breaks in half CLEANLY. This is when seeds have just begun to form, and the pods are 4"-8" long. Hold stem with one hand and the pod with the other hand to avoid pulling off branches which may continue to produce. When harvesting bush beans, some recommend pulling up the whole plant at once, since bush beans produce primarily all at once. After harvest, the nitrogen-rich plants make great compost material!