Feed lawns, plants with soy

A gardener asks, "What should I feed my lawn?" The answer is soybean meal, a fertilizer that could feed any hungry plant. Another gardener asks, "What can I feed my roses?" Soybean meal. "What about my rhododendrons?" Soybean meal. "What about...?" Soybean meal. Soybean meal. Two pounds per hundred square feet.

Soybean meal is what remains after you grind up and squeeze the oil from soybeans. The meal is rich in protein, which is why it is usually sold as a feed for pigs, cows and chickens (and is available in feed stores). But put soybean meal in the soil and microorganisms there first cleave the protein molecules into amino acids, then tear apart the amino acids to create ammonium ions, and, finally, nitrate ions. Read the fine print on any bag of fertilizer, and you will see that the nitrogen within is supplied as ammonium and-or nitrate ions, which are the two forms of nitrogen palatable to plants.

When you add soybean meal to the soil, you are tapping into an elegantly designed natural system for feeding plants. Wet, warm weather spurs microorganisms to work hardest, and this is the same weather that makes plants hungry and grow fast. Also, plants that like very acidic soils enjoy their nitrogen served up as ammonium ion, which is the kind of nitrogen that soybean meal becomes in such soils.

Although soybean meal can feed any plant, it is not unique in this respect. Any organic material rich in protein would serve just as well. In some places you can put your hands on such exotic, nitrogen-rich byproducts as hoof meal, feather meal or horn dust. More familiar is cottonseed meal, typically packaged in 5-pound cartons and lined up on the store shelf with other fertilizers. But soybean meal is inexpensive and generally available.

Two caveats are in order when using soybean meal or any of the other fertilizers mentioned in the previous paragraph. Early in the season, when the soil is cold, microorganisms are sluggish. Succulent vegetables, such as lettuce and celery, might need a boost from some quick- acting, soluble fertilizer -- either a synthetic fertilizer or an organic fertilizer such as fish emulsion.

And although soybean meal is rich in nitrogen, nitrogen is not the only food that plants need. Offer plants a balanced diet by also constantly enriching the soil with plenty of bulky organic materials, such as leaf mold, wood chips, straw, manure, and -- best of all -- compost.