Lawn Aeration by Bruce Clark An aerator helps the soil breathe; a power rake gets it ready for seeding. Lawn looking thin, bare or brown? You can revitalize it in a weekend using just one or two tools from a local rental or garden center. The power core aerator loosens any compacted soil in your yard and breaks up thatch. Thatch is a cushion of old, partially decayed grass roots and stems that develops in many sodded lawns. It separates the actively growing crown of the grass plant from the soil surface. The power rake is equipped with vertical fixed tines to cut the soil and prepare a thinned-out lawn for reseeding. For you Northern homeowners whose lawns experience a hard freezing winter, the first dew in August is your signal that it's time to aerate to ensure lush grass next spring. For homeowners in warmer or more arid states, aerate your lawn next spring to boost those warm-climate grass varieties before they go dormant in mid-summer. Most lawns, whether seeded or sodded, are planted over a fairly skimpy layer of topsoil. Over time, lawn mowers, pets and pick-up football games compact the soil, making it difficult for air, water and vital nutrients to penetrate to the grass roots. Your challenge: to restore healthy soil conditions that nurture your lawn. To loosen and aerate the soil, rent a power core aerator. They're available at rental centers, plus some hardware stores and garden centers. An aerator rents for about $20 per hour. This self-propelled lawn machine employs a row of evenly spaced, hollow, 3/4-in. dia. spoons that penetrate the soil up to 3 in. deep. They pull out soil plugs, leaving a pattern of holes in the lawn that will readily absorb water, air and nutrients. Our rental power core aerator may differ from what you'll rent, but they all work basically the same. Ask your rental center to demonstrate the machine's controls and the procedures for turning and reversing, then follow these general guidelines: To avoid damaging the aerator's spoons and scarring your sidewalks, driveways or steppingstones, run the machine across them with the rotating spoons in the raised position. Flag and avoid lawn sprinkler heads or you'll risk busting them and springing a leak. Don't use aerators on hillsides with a slope exceeding 35 degrees. For the safest hillside operation, go up and down hills rather than across them. MAKE TWO PASSES across the lawn perpendicular to each other with a power core aerator so that the aeration holes are spaced 2 to 3 in. apart. Set the spoon penetration by turning the depth control knob to the deepest setting. For operation on hills and uneven terrain, load or remove one or both onboard weights to increase stability. RUN the aerator in the morning when the turf is cool and moist (but not soggy). You want the aerator's hollow spoons to easily penetrate 1-3/4 in. to 2-1/4 in. into the soil and pull out full-length dirt plugs. If a large, straight-slot screwdriver can't easily penetrate 3 to 4 in. into the soil, the soil is too dry. The day before aerating, water the soil till it passes the screwdriver test. Mow your lawn just before watering and aerating it. PREPARE soil for reseeding using a power rake. Its solid tines slash through any thatch mat and score the surface of the soil. Power-rake only after aeration and in the afternoon, after the morning dew has dried-so the dead grass and roots lift out loosely without clumping. Make two opposing passes with the power rake, each 45 degrees across the pattern used by the power aerator. Often, older lawns that haven't been aerated and maintained have turf that's scraggly and thin. After power-aerating the lawn, your first step to correct this problem is to rent a power rake-a gas-powered lawn machine that's roughly the size of a lawn mower but 1-1/2 times heavier. They're available at rental centers for about $15 an hour. The power rake is much less complex than a core aerator and easier to operate. Ours wasn't self-propelled; we pushed it around the yard. It should be operated at full throttle to maximize the power of the continuously spinning, solid, vertical tines that pull dead grass and lawn debris up to the lawn surface, and leave a pattern of 1/4-in. deep slits in the soil surface. Used after the aerator, the power rake will prepare the soil to receive seed and/or fertilizer. Follow these tips for using a power rake: Some power rakes (like ours) have fixed vertical tines for slitting the soil. These are better for penetrating any thatch and getting to the soil surface than loose, "flail-type" tines. Rent a power rake with depth controls that can be set the tines to cut 1/4 in. deep into the soil for seeding. For lawns with smaller areas of bare spots or thinned areas around the perimeter that you can't efficiently power-rake, prepare the soil for seeding by using a flat-nosed shovel to chop slits in the soil 1/4 in. deep. After seeding, use the knuckles on the back of a fan-type rake to "scuff" the seed into the soil. Power rakes work best on lawns with even terrain. On bumpy lawns, a power rake will scalp the high spots and ride over dips in the lawn without cutting the soil. Power aerators and power rakes can usually be rented by the hour, half day or day. Because these two machines are in high demand (especially on weekends), ensure that your work plan will flow uninterrupted by reserving both machines in advance. Save some money by first renting the aerator, then picking up the power rake when you drop off the aerator. Rejuvenate your lawn using these strategies: Budget your time: You should be able to aerate and power rake up to 5,000 sq. ft. in three to four hours. Avoid renting aerators that are equipped with spikes and only roll over the lawn and perforate it. The core aerators that actually remove soil plugs-like the one shown-are vastly superior because they open up more soil volume. Recruit a buddy who has either a pickup truck or a minivan to help wrangle these heavy lawn machines home and back to the rental center. Inquire whether your rental center offers delivery and pickup (at additional cost). If your grass is thinned out, adopt a more aggressive plan for total lawn rejuvenation. Between passes with the power RAKE, always use a hand rake to loosen dead grass and lawn debris to ensure that new seed or fertilizer will contact the soil. If you reseed your lawn, make two passes with a rotary spreader. Each pass should contain half the recommended lawn seed for your square footage of lawn. Run it after each time you hand-rake in the same direction the power rake slit the soil so more seed can drop into the core holes and slits without being raked off. RUN the aerator in the morning when the turf is cool and moist (but not soggy). You want the aerator's hollow spoons to easily penetrate 1-3/4 in. to 2-1/4 in. into the soil and pull out full-length dirt plugs. If a large, straight-slot screwdriver can't easily penetrate 3 to 4 in. into the soil, the soil is too dry. The day before aerating, water the soil till it passes the screwdriver test. Mow your lawn just before watering and aerating it. If your lawn has excess thatch or you've laid new seed, use the spreader and apply decomposter mix to both accelerate the decay of thatch left in the turf and increase seed germination and rooting. Complete any plan by watering your lawn with up to 1/2 in. of water for thin lawns and 1/4 in. for bare soil. Overwatering will wash away the seed and nutrients. If you've never used an aerator or a power rake, practice on an isolated section of your yard. The first time I used a power core aerator, it nearly dragged me off the lawn and into the street. My uncle still enjoys recounting that story.

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