How often should you aerate your lawn?

Why bother

Packed soil shuts out water and air from the roots. A thorough-tier job. Skippable when life's busy, worth it when it isn't.

Why it's a range

Clay and heavy traffic want it yearly. Sandy, quiet lawns go two or three.

What the job involves

1. Mow a bit short and water the day before, so the soil is moist but not soggy. Dry clay will not give up its plugs, and a swamp just smears.
2. Run a core (plug) aerator over the lawn, then go again at a right angle to the first pass. You want roughly 20 to 40 holes per square foot, a proper checkerboard of pulled cores.
3. Leave the soil plugs where they fall. They look like the lawn made a mess of itself, but they break down over a couple of weeks and feed the grass back. Raking them off defeats the point.
4. While the holes are still open, overseed and feed and keep it watered. This is the one window where seed and fertilizer get straight down to the roots instead of sitting on top.

Do it yourself, or pay someone?

DIY is fine for a flat, average yard: a gas core aerator rents for about $65 to $100 a day (around $35 to $65 for a half day), plus a refundable deposit. Fair warning, the thing is heavy and the work is grim, worse on a slope. Hiring out runs about $75 to $250 a service ($140 average), or roughly $0.10 to $0.35 a square foot, and it is often cheaper bundled with overseeding. Pay a pro for big, sloped, or hard-clay lawns.

What skipping it costs

$300 to $4,000 and up, eventually, if compacted soil thins or kills the turf and the lawn needs putting back. On clay or a high-traffic yard, skipping aeration starves the roots of air and water, so over a few seasons the grass thins, thatch builds, and bare patches spread. The cheap end is a professional reseed or overseed of a damaged lawn, about $250 to $350. Angi puts a full lawn renovation at around $4,000 on average, and a lawn dead enough to need new sod runs $1.50 to $4.00 a square foot installed, which is several thousand on an average yard. It is a slow, probable outcome, worst on clay, not a guaranteed bill. Pulling a few plugs once a year is the cheap end of that.

Signs it's overdue

• Water pools or runs off after rain or watering instead of soaking in, and the ground feels hard underfoot.
• The grass is thin, patchy, or sulking despite watering and feeding, with shallow roots and a spongy thatch layer over half an inch thick.
• A screwdriver is hard to push into the soil, or the worn paths and clay patches stay bare no matter what you do.

When to start thinking about it

Give yourself about 7 days' notice. That's when Grumpty starts grumbling, so it doesn't land on you the day it's due. Mark it done and Grumpty sets the next one, every 12 months, so you can go back to forgetting it exists.

Questions people ask