Over time the soil beneath our lawns can become as hard as a brick due to soil compaction. This reduces pore space and increases soil density, resulting in problems for any gardener.
When no space is between particles, the movement of air, water and nutrients in the soil decreases. Water does not infiltrate into the soil and runs off site. Turf suffers as roots struggle to fill basic plant needs.
Most soil compaction occurs within the top 3 inches of the soil profile. Compaction may result from heavy equipment traffic, the layering effect of differing soil textures when gardeners top dress a lawn, or repeated tilling or aeration to the same depth. Many times we call this a plow pan in the soil.
Check for soil compaction by inserting a blunt rod or screwdriver into the soil to see how hard the soil is in a specific area.
The best way to combat compaction is with aerating.
Aeration opens channels in the soil through which air, water and nutrients can move more freely.
Typically in ideal conditions, soil with good structure allows water to move into soil (infiltration) and then move through soil (percolation). The movement of water improves with aeration. And hard soils soften with increased space between soil particles. Good soil structure is important for nutrient uptake by the plants, root growth and soil water recharge after a long hard drought.
If you need to aerate, use an aerator that pulls plugs of soil using hollow tines. One type of aerator is made of spikes, but the effect is limited and not as effective.
When you do aerate, ensure enough soil moisture is available to allow the tines to go through the soil fairly easily. Do not aerate when the ground is too soft, such as right after a soaking rain.
If the soil is too dry, the aerator will just dance across the lawn, not penetrating into the ground.
Aeration is best for the lawn when it is growing. For fescue, fall or spring is ideal. For Bermuda or zoysia grass, the summer is ideal.
Aerating can be done once a year or once every other year.
In extremely compacted soils, simple aeration may not be enough to fix the problem. In that case, a total lawn renovation may be needed.
If you have questions about when or how to aerate your lawn, just give me a call at the office.
Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, www.hallcounty.org/extension. His column appears weekly and on gainesvilletimes.com/life.