Should I aerate my lawn? If so, how do I do it? (ASK Around)

What is aeration?

Did you know plant roots need to breathe? Natural soil is only around 50% solid materials, and the other 50% is empty pore space where air and water flow through. However, when our lawns get lots of traffic from feet, paws, and wheels, these tiny pores collapse, and the soil becomes dense and compacted. This means it’s time for aeration!

Diagram via UF: healthy soil on the left vs. compacted soil on the right – no room to breathe! (Image source UF blog) 

Aeration is the lawn care practice of creating holes in your soil to loosen it up and allow airflow to the grass roots. These holes let your soil breathe, improve drainage, and can also help fertilizers or seeds get down into the soil where they need to go. Aeration reverses soil compaction and helps fight thatch buildup in lawns. There are several different machines and tools you might use to aerate your lawn – read on to learn more!

When should I aerate my lawn?

Most lawns need aeration every 2-3 years, but high-traffic lawns might need it annually. Soils with high clay content might also need more frequent aeration.

How can you check if your lawn is due to be aerated? One rule-of-thumb is the screwdriver test: try to insert a screwdriver straight down into your soil. If you meet with a lot of resistance, it’s a sure sign your soil is compacted and needs aeration. Other signs you can look for are puddles forming due to poor drainage or a spongy lawn indicating thatch buildup. If you’ve recently had construction work on your home or there’s been heavy machinery on your lawn for any reason, it's definitely time to aerate.

As for what season to aerate, it’s important to make sure your lawn is actively growing, since the aeration process can cause damage to dormant grass. For cool-season grasses, fall is usually a good time, while late spring to early summer is usually good for warm-season grasses.

How should I aerate?

Once you know your lawn needs aeration, the next question is what kind of equipment to use. There are three categories of aerators: core (or plug) aerators, slice aerators, and spike aerators. Spike and slice aerators rearrange the soil without removing anything, either by poking holes (with spikes) or making cuts (slices) through the soil. These strategies might work well for sandy or loamy soil, but they can also make compaction worse by pushing soil closer together around the new holes. These kinds of aeration are not recommended for clayey soils. Some people do spike aeration by hand using a tool like a pitchfork or by foot using spiked boots! While inexpensive, these methods are quite labor-intensive.

The best option for aeration is usually core aeration, also known as plug aeration. This process uses small metal tubes to remove narrow cores of soil, around half an inch wide and up to 3 inches deep. Your local lawn care store likely has core aeration equipment options available to rent, since most people only need to use them once every year or two. Rolling, tow-behind, and stand-on aerators can all be effective for core aeration, and the best option for you will depend on your budget and the size of your lawn.

When you’re ready to aerate, there are some steps you can take before, during and after to get the most out of it:

• First, make sure your soil is moist (but not water-logged) by irrigating beforehand or aerating the day after a rainfall. This will make aerating easier as your soil will be softer.
• You may want to mark any in-ground sprinklers or pipes with flags so that they don’t get run over and damaged.
• During aeration, make sure to pay special attention to and make multiple passes over any particularly compacted area.
• After aeration is a great time for fertilizing or overseeding, since the new holes will help increase contact between fertilizer or seeds and the soil.
• What about the little soil cores left on top of your lawn? They will break up soon due to normal yard work such as mowing combined with rain and the elements. It’s important to leave them on your lawn to return important nutrients and materials to the soil.

As always, if you have specific questions about your lawn, reach out to SoilKit and ASK an expert!