Crop Rotation and Legumes
More than one backyard farmer has enjoyed a bumper crop of tomatoes one year, only to be disappointed the next year when his or her beefsteak tomatoes turned out more like cherry tomatoes. The solution is either to build the soil up again from scratch, or practice crop rotation.
The southern United States had been plunged into poverty by the U.S. Civil War, and crops were struggling. Professor George Washington Carver of Tuskegee University needed to find a way to grow crops again to feed the people. The soil had been depleted by generations of cotton growth, and Dr. Carver found that growing peanuts* restored the soil's fertility.
The wonderful and useful thing about peanuts was the bacteria that attach themselves to the roots. The bacteria on the roots of peanut plants fix nitrogen from the atmosphere to the soil, where it becomes an important nutrient for growing plants.
Although we call them nuts, peanuts are actually members of the legume family, a kind of bean. Legume roots form nodules, homes to several species of bacteria, collectively known as diazotrophs. The diazatrophs on legume roots release ammonium, a nitrogen compound, into the soil, where other bacteria turn it into nitrites and nitrates. Nitrates are taken up by plants to use for making amino acids which, strung together, make up proteins.
Edible legumes you can grow in your veggie garden include several species of peas, beans, and even clover (sprinkle it onto your salad for fresh flavor). Plant pea seeds in early spring so that they can get a good start in cool weather. They tend to wilt in the heat of summer. Choose a location that gets at least 6 hours of full sunlight per day. Plant your seeds in soft, rich soil at the depth specified on the seed packet, and keep the soil slightly moist. You can use either tomato cages or pound sturdy bamboo stalks well into the ground for your vines to grow up. When seedlings first sprout, you will want to use a fine spray when you water, to keep from them washing away. Pick your peas when stop growing but while they are still green. Beans should be planted much the same way, in the late spring so that they can flourish in the warm summer months. Pick beans before they are completely mature for the best flavor. Red and white clovers are perennial herbs, usually planted in the fall. Pick the young leaves and flowers before they become permanent.
After a season of growing legumes, your soil should be ready for replanting in other veggies. If legumes do not appeal to you, please see my instructions for lasagna gardening. Happy eating.
*Professor Carver invented peanut butter to give peanut farmers a finished product to sell.