Weeds are divided into two classifications: broadleaf (dicot) and grassy (monocot). They are then subdivided into annual or perennial, and further, according to growth style such as clumps or patches. Annual weeds come up just once each season; the plant then dies and the same plant will never grow again. Typical annual weeds include crabgrass, barnyard grass, goose grass, and foxtail. Perennial weeds grow year after-year, that is, the same plant blooms again and again. Typical perennial grassy weeds include redtop, bent grass, coarse fescue, and timothy. Fertilizers with chemicals are available to control all of these weeds; the specific weeds are usually listed on the bags.
Lawn disease preventers are available with or without fertilizer; they may be used on mixtures of bluegrass and fescue, perennial ryegrass, St. Augustine, and bahia grasses. They prevent leaf spot and other fungus diseases. Lawn insect-control products take care of such pests as cutworms, lawn moth larvae, and flea beetles; they are available with or without fertilizer. For the West Coast, the products contain chemicals to stop Japanese beetles, European chafer, sod webworms, and May and June beetles.
A moss control/fertilizer is available for use in the extreme western sections of Oregon and Washington. Spread fertilizers according to the directions on the package. Some manufacturers build in a margin of error for fertilizers; others don’t. If too much fertilizer is spread on the grass, the grass will burn brown from the chemicals. Therefore, resist the temptation to apply more fertilizer than recommended. Set your spreader as recommended by the manufacturer, even though the amount of chemical being distributed may seem skimpy.
Different types of nitrogen (the first number on the label) have different methods of release and different performance characteristics. The types are listed on the label along with the correct spreader settings. Ammoniacal nitrogen is released quickly and is absorbed almost immediately by the grass; it produces very fast greening. If this chemical is not spread according to the manufacturer’s recommendations, it can burn the grass and turn it brown.
Water soluble nitrogen is released at varying rates by rain and sprinkling systems. The chemical starts to work about three days after it has been spread and continues to release nitrogen gradually for about three weeks or more. This type of nitrogen is safer than ammoniacal; it also provides good, extended greening. Water insoluble nitrogen is slow to release; the breakdown starts about two or three weeks after spreading and continues for several months. The chemical is converted by soil microorganisms. Some manufacturers use only one type of nitrogen; others mix a combination of all three, which is explained on the label. water soluble bag manufacturers