Warm season home lawns (bermuda and zoysia) are not designed to be maintained like golf course greens and therein lies the problem. Because golf greens are constructed with a very specific soil mixture they can be maintained at short mowing heights. Compaction is also a problem on the course but the greens are aerated multiple times every year to reduce the problem. When sod is installed at a home the soil present on the property is not properly prepared. In fact, in most subdivisions any quality soil is stripped off as the builders seek to level lots. The subsoil is a very low quality soil for root systems and it takes decades to rebuild quality soil. Just adding “top soil ” to the yard before sodding is not the same thing as completely constructing a specialized subsoil structure just for the turf.
If the lawn is then top dressed with sand, compaction levels increase even more. Short mowing with a reel mower will further increase compaction. Root depth becomes shallow because the soil is too compacted for deep root growth and the turf cannot produce adequate food because the leaf blades are so short. Subsequently the turf is not healthy and is more susceptible to winter kill, heat injury and attack by fungal disease pathogens.
As you move into August mowing heights must be raised before the first frost to allow the turf to increase its top growth and produce food for storage in the roots and to build new roots. Without this recovery period winter kill is always a possibility. We are not saying that you can’t reel mow your turf but if you do there are cultural practices you must follow to reduce problems that are created by this type of mowing.
If you do not aerate, your compaction level increases. In highly compacted soils, soil pore spaces are reduced and this decreases the available water to the plant roots. Clay already has very small pores and can already reduce water availability to the plant roots. Compaction makes this worse resulting in poor root growth.
Also, as more water is held in the pore spaces there is less room for oxygen so the roots begin to suffer oxygen deficiency. This also results in poor root growth.
Another effect of compacted soils is that the roots, already unable to properly absorb nutrients and moisture essential to plant growth and health, must now spend an increased amount of energy and resources pushing through compacted soil. This energy is being taken away from other growth processes in the plant weakening the entire system. You can see that eventually the plant becomes severely weakened and is more susceptible to pests and weather influences.
While yearly core aeration cannot completely reverse compaction it can manage it within tolerable levels.