Controlling weeds before they take control of your garden
Perennial weeds, such as bindweed, dandelion, nutsedge and quack grass, are the most persistent, resilient and toughest to control. Dig often and dig deep!
Certain weeds favour specific types of soils. Stinging nettle only grows where soil is nutritious, especially where nitrogen and phosphorus are plentiful. Most weeds, however, grow best in poor, nutrient-deficient soil—thyme-leafed spurge will even grow at the edge of a lawn beside an asphalt driveway, while dandelion grows well in compacted soils low in calcium and high in phosphorus. Weeds such as plantain and prostrate knotweed have special roots to deal with excessively compacted soil. Another group of weeds, called “pioneers” because they're the first to recolonize after a fire, includes fireweed, which thrives on the nitrates found in ashes.
There are many ways to tackle a weeding problem. For large areas you can use an old-fashioned hoe, but in small areas it's best to weed by hand or with a trowel so desirable plants nearby are not damaged.
To make weeding easier, water the day before to moisten the soil. Hoe on a dry, sunny day so that small seedlings will bake when they're uprooted. A Dutch hoe, circle hoe or swoe slices off weed seedlings or young weeds just below ground level.
When removing a mature weed manually, you must get the entire root to be successful. Use a cultivator to loosen the soil around large weeds; then pull them straight out. Use a garden fork, not a spade, to weed a border. A fork keeps weed roots intact; a spade slices right through them, leaving behind pieces that might regrow—purslane, for example, regrows from very small pieces. Remember to check after a few days and get any ones you missed.
Black plastic or mulches smother weeds by removing light and air. Other remedies such as boiling water, steam irons, mechanical wallpaper strippers, hot-air paint strippers or propane torches have their advocates as well.
The saying "One year's seed gives seven years of weeds" is true. One important key to successful weed control is to remove weeds (or at least the seed pods) before the seeds ripen. Cut down those weed-forming seed pods with a line trimmer, hedge shears, hand pruners or lawn mower.
An innovative weed-control strategy is to use natural insect predators, moths, micro-organisms, parasitic fungi or disease spores to fight weeds. Research is being done on the abilities of certain plants to control weeds by releasing toxins into the soil. Quack grass is highly effective for this, but sorghum, sunflowers and some types of cucumbers also have this ability. Who knows? The weeds of today could be an integral part of the weed killers of tomorrow.