Legume fruit grow in pods that split open along a seam. Common examples of legumes are peas, beans, soybeans, and peanuts. In my way of thinking legumes are very important for two big reasons:
- They're a good source of dietary fiber which helps keep diabetes (among other maladies) at bay.
- They're plants that perform nitrogen fixation in soil.
Nitrogen fixation is an important function in gardening, particular the organic variety. "Fixing nitrogen" is a process where gaseous nitrogen from the air is absorbed by the plant which, eventually, dies and then is released back into the soil. So, for the fixing to actually occur, the plant has to die and the roots to have some degree (I don't know how much) decay to release the nitrogen. According to my reading (admittedly, my recollection of college chemistry is very rusty), atmospheric nitrogen that is absorbed is is compound whereas the nitrogen that's released through decomposition is singular from a molecular standpoint. Nitrogen in soil is important for many things, but most obviously peppers and tomatoes love it. That is one reason why crop rotation is important: nutrient replenishment.
Growing legumes (in my garden: peas or beans) is rather simple. You plant seeds at the recommended depth (1" or so) and spacing (4"-6" apart), do some light fertilization, and water. They come in two primary varieties: bush and pole. Pole beans are grown up something, such as up a pole. There are a number of ways of accomplishing this upward growth: poles, trellises, arbors, and a native way to do that is through companion planting around corn stalks. While it's implied that bush beans have no need for trellising, my experience is that they still need trellising just something less impressive than pole beans. 2'-3' high vs 4'+ with Scarlet Runner Beans being listed as 10' long.
Companion planting was a mixed bag for me last year. I had read that marigolds assist with pest deterrence. That may be the case, but Mexican Bean Beetles paid no attention to it other than, perhaps, thinking that mine were both plentiful and pretty. Despite my attempts at using Neem Oil, my beans (red, green, and lima) were wiped out by the Mexican Bean Beetle. I have since read that Summer Savory, Rosemary, and Petunias are good companion plants for beans. In addition, Nasturtiums attract predatory insects which may also help. I'll be planting all but Summer Savory - my reading indicated that it takes more constant care than my somewhat constrained schedule can support. I'll apply insecticide soap to supplement, if needed.
Nutritional Information on Boiled, Unsalted Green Snap Beans
Green snap beans are an "excellent source" (20%+ RDA) of Vitamin K and are a "good source" (10-19% RDA) of Vitamin A, Folate, Manganese, and Fiber. There are also notable quantities of Riboflavin, Thiamin, Vitamin B6, Niacin, Copper, Iron, Magnesium, Phosphorous, Potassium, and a host of essential amino acids. All are presuming 1 cup consumption.