Depending on the kinds of weeks in your lawn, spring weed management can be easily done, said a University of Illinois Extension horticulture educator.
Richard Hentschel reviewed some typical weed problems faced by homeowners and ways to address them.
"If your concern is annual crabgrass, then any of the commercially available crabgrass preventers will work well," he said. "Crabgrass is a warm-season annual. When you are applying a control product, you are applying a chemical that prevents the crabgrass--and other annual weed grasses--from germinating.
"Apply too early and the protection wears off before the crabgrass seeds stop germinating for the season and you end up with some crabgrass in your lawn."
If you are going to do any re-seeding or overseeding of bare or thinned areas, most crabgrass control products will also control your new seed, so avoid those products in those areas. Tupersan (chemical name Siduron) is one crabgrass-control product labeled for use at seeding time. Be sure to read the label of any product to be sure what you are applying.
"Broadleaf weeds provide an additional challenge to the homeowner," he said. "Not only do we have the weeds in our lawn in the spring, but they will also be germinating all summer, so even if we control them in the spring they will be back in the fall.
"A better way to control broadleaf weeds is to wait and do a late-summer application that will take care of those weeds from spring and any broadleaves that have germinated during the summer. A big benefit besides better weed management is that very little harm will come to your flowers, vegetables, groundcovers, shrubs, and trees when making those late-summer applications of broadleaf weed control materials."
Hentschel said the most troubling weeds can be those perennial grasses like tall fescue and quack grass.
"They behave just like our preferred lawn grasses, and any material used to control either weed grass will control our lawn grasses," he noted. "These areas will need to be spot-treated and later you can re-seed or sod."
At the same time you are thinking about weed control, remember mowing.
"While you are waiting to mow for the first time, dig out the lawn mower and prepare it for the mowing season," he said.
Drain and replace the old gas with fresh gas and put the old gas into the family car. Fresh gas ignites much better than old, stale gas and is greatly appreciated by those who have to pull start the mower.
"If you did not change the crankcase oil last fall, now is the time," he said. "Another item easily overlooked is the air filter. Make sure to clean and/or replace the air filter. A dirty air filter can cause hard starting and causes more air pollution from the mower engine during the summer.
"If it has been a couple of years or more since the spark plug was changed, a fresh spark plug will definitely help you start the mower engine more easily."
Spring is also a good time to check out the underside of the mower deck. Pull the wire off the spark plug and remove the cutting blade to make easy access to the underside of the deck. Use a wire brush or putty knife to clean the caked grass and debris from underneath the deck. Have the blade sharpened.
"The last thing you can do is make sure the mower is sitting flat and that all the wheels are adjusted to the same point," he said. "Your lawn will always look better by setting the mower deck to cut the grass longer than shorter. A taller cut will leave the lawn looking greener, and you will avoid scalping those high spots.
"A shorter lawn allows more sunlight to reach the soil surface, drying out the grass roots, and allows the germination of weed seeds. Your goal should be to remove no more than one-third of the grass blade at any mowing, no matter what the cutting height is. A clean deck, a sharp blade, along with a flat mowing deck will mean a much better-looking lawn when you are done."
Hentschel added that lawns will have areas that grow sooner than others, such as on the southern and western exposures. These should be mowed as soon as the grass is tall enough, even if the rest of the lawn is not ready. Freshly seeded areas should be mowed as soon as they are ready, too. The grass plants will begin to fill out as soon as you start to mow.
"Lawns naturally green up and begin to grow without an application of fertilizer each spring," he said. "The goal should be to extend that spring greening without causing excessive growth.
"You can wait to apply that spring fertilizer until after you have mowed the lawn two or three times. Using a combination weed-and-feed type of material can be a compromise between good weed control and causing early excessive growth. Consider making that crabgrass control application separately from your fertilizer application."
Source: Richard Hentschel, Extension Specialist, Green Industry Programming, hentsche@uiuc.edu
