Less is more when it comes to spring lawn care

It's a Minnesota tradition: On the first warm sunny day of spring, joggers are wearing shorts, and someone is out raking their lawn.

Our enthusiasm for yard work seems to rise with the temperature. This year, we think, I'm going to fertilize my grass. This year, I'm going to get rid of that creeping Charlie. This year, I'm going to seed those bare patches.

Unfortunately, the best time to do most of the things that improve our lawns is from August to October. But there are steps you can take now.

First, hold back on the hard raking. Spring turf is tender, and you don't want to rip grass up by the roots. Don't rake if the impressions of your shoes remain on the turf after you've walked on it. Use a springy, light rake to remove the remains of last year's leaves but stay off the lawn until it is dry.

If your lawn is hard, bumpy and the site of hard use by kids or dogs, consider aerating. While the best time for aeration is in the fall, spring aeration — paired with a repeat in autumn — can really help an abused lawn. Many weeds, including pesky prostrate knotweed, thrive in hard-packed soil and can start to take over as grass suffers.

Don't bother stomping around the yard with the spiked shoes that some garden catalogs sell. Aeration — pulling plugs of soil from the ground so that nutrients and water can more easily reach grass roots — is best done with a core aerator, a machine that looks a bit like a snowblower. Aerators, which can be rented at many rental and garden centers, pull 3-inch-long plugs of soil that look like little cigars from the ground.

To make it easier for the machine's prongs to penetrate the lawn, give grass a good watering or wait until it has been soaked by a good rain. The aerator should be run at least two or three times over a lawn in different directions. If you want to cry when it's done because it looks so awful, you've done a good job. Lawns recover amazing quickly from aeration, with the soil plugs totally disappearing in about 10 days.

Aeration also helps lawns absorb fertilizer, and minimizes runoff of both nutrients and water. While the University of Minnesota Extension Service suggests fertilizing low-maintenance lawns in August and October, you can fertilize in May and June, too. Remember that leaving finely chopped grass clippings on the lawn through the summer acts as a nitrogen fertilizer.

For homeowners with weed problems, a weed-and-feed or a fertilizer with crab-grass preventative can be applied in spring. Crab grass, an annual weed, begins to germinate when night soil temperatures reach 52 to 55 degrees, according to the U of M. That usually happens the last week of April to the beginning of May.

Since few of us take the temperature of our soil, a guideline that may be easier to remember is to apply crab grass pre-emergent when you see lilacs beginning to bud. Only use weed preventers where you've had a problem before, and remember that crab grass may sprout earlier near sidewalks and driveways because of the warmth.

It seems logical that spring would be the best time to plant grass seed, but that's another job that's best done in August and September. That's because weed seeds germinate mostly in the spring, so there's less competition for grass seed that is planted as fall approaches. But now is a good time to lay sod if you're prepared to keep it watered through the hot summer months.

As for killing weeds, perennials like dandelions and creeping Charlie are easier to dispatch when the weather cools in late summer and the plants are directing their energy to their roots. But you can rake out a lot of creeping Charlie in the spring — watch the grass! — and dig dandelions.

Mary Jane Smetanka is a master gardener and Minneapolis freelance writer.