By: Tony Koski, Extension Turf Specialist

A few thoughts on lawn aerification (core cultivation) from now through the fall.

1. If lawns aren’t being regularly watered (as is the case in MANY communities), the lawns will likely be so hard that aerification will not be terribly effective. That is, plugs will not likely be pulled from such hard lawns without the benefit of a good soaking rain or a couple of days of intensive irrigation.
2. Lawns that are stressed due to some of the more extreme watering restrictions will not likely benefit from fall aerification (or earlier “beat the fall rush” aerification being promoted by some companies right now). These stressed lawns may actually suffer additional stress (traffic stress from the equipment, increased drying because of open holes).
3. Aerification holes will promote drying of the soil if they do not heal over quickly. On actively growing, regularly watered lawns the holes heal quickly. On stressed, infrequently irrigated lawns the holes will stay open longer and thus promote drying of the soil – something we don’t need at this point. Plus, drought stressed and (especially) non irrigated lawns will not produce much in the way of new roots this fall – even if they are aerified. In fact, they may produce MORE roots if left undisturbed (NOT aerified) than if they are aerified.
4. Those lawns that are being watered enough to get good penetration/plug pulling would probably benefit because they are growing “normally” (new roots will form, holes will heal over).

So, lawns that do not appear to be under stress and are irrigated regularly enough to allow effective pulling of cores can benefit from fall aerification. Where watering restrictions have resulted in stressed lawns and hard soil, aerification may not be effective and may actually cause more harm than good.