Maybe the neighbor’s lawn is always greener and has fewer weeds, or maybe you’re just looking at yours too closely. The best way to minimize weeds is to keep a nice, dense green lawn. Healthy lawn grass can choke out weeds. That, a dandelion digger and some time spent communing with nature are still your best bets. Unfortunately, a weed-free lawn is a myth unless you live in a bubble that can keep wind, weather, squirrels and the neighbor’s cat out.
Mow lawns the correct height and mow frequently. Kentucky bluegrass, Tall fescue and St. Augustine grasses all should be mowed at three inches. Bermuda and Zoysia grass should be mowed at 1 to 1 1/2 inches. Never take more than a third of the blade off; it causes the grass to lose moisture and nitrogen. Mow more often in the spring. While you’re at it, sharpen that mower blade once or twice a season. Sharp cuts heal fast, and dull blades shred leaves, resulting in excessive loss of water and nutrients.
Water your lawn infrequently but completely. Your lawn needs about an inch of water a week. If it does not get it from precipitation, water it deeply once to make up the deficit. Water your lawn during the early morning hours when the cool air keeps moisture near the ground. Leave a can or rain gauge out to measure precipitation and irrigation totals. Surface watering only nourishes weeds. Grass roots grow much deeper.
Apply the right fertilizer at the right time. Have your soil tested at your university agricultural extension to find out what kind of fertilizer your lawn needs and how often it should be applied. All lawns need nitrogen in the spring and fall. Never apply fertilizer in the heat of summer. Grass clippings can add up to 25 percent of the nitrogen necessary for a healthy lawn. If the topsoil is thin, you may need to make additional applications or top dress with manure or topsoil.
Learn to target weeds and use herbicides when they will be effective. Pre-emergent herbicide prohibits seed germination and is effective in early spring and late fall. Broad leaf herbicides must make contact with the leaves of weeds such as dandelion, plantain and chicory. A targeted herbicide such as glyphosate is a good choice for broad leaf weeds. Dig up quackgrass. It’s often mistaken for crabgrass, but since it spreads by rhizomes, a pre-emergent designed to kill seeds will not make a dent in it. Never underestimate the value of persistence and a good dandelion digger.
Look for signals. Moss, algae and yellow nut sedge, a thick grass-like weed with an impressive panicle, are signals of soggy soil. Moss and algae tolerate infertile or acidic soil. Knotweed grows in compacted soil. These and other plants signal problems with soil that must be addressed, often by digging up sod, amending or adding topsoil and re-seeding or re-sodding.