Fall Turf Care

September is the optimum time to power rake or core-aerate tall fescue and Kentucky bluegrass lawns. These grasses should be coming out of their summer doldrums and beginning to grow more vigorously. This is a good time to consider what we are trying to accomplish with these practices.

Power raking is primarily a thatch control operation. It can be excessively damaging to the turf if not done carefully. For lawns with one-half inch of thatch or less, I don’t recommend power raking but rather core aeration. For those who are unsure what thatch is, it is a springy layer of light-brown organic matter that resembles peat moss and is located above the soil but below the grass foliage. Power raking pulls up an incredible amount of material that then must be dealt with by composting or discarding.

Core-aeration is a much better practice for most lawns. By removing cores of soil, core-aeration relieves compaction, hastens thatch decomposition, and improves water, nutrient, and oxygen movement into the soil profile. This operation should be performed when the soil is just moist enough so that it crumbles easily when worked between the fingers. Enough passes should be made so that the holes are spaced about 2 to 3 inches apart. Ideally, the holes should penetrate 2.5 to 3 inches deep. The cores can be left on the lawn to decompose naturally (a process that usually takes two or three weeks, depending on soil-type), or they can be broken up with a power rake set just low enough to nick the cores, and then dragged with a section of chain-link fence or a steel doormat. The intermingling of soil and thatch is beneficial to the lawn.  (Ward Upham)

We are often asked, “What’s the best shade grass for Kansas?” The answer is simple but requires explanation. Tall fescue is the best shade grass for Kansas. That does not mean that tall fescue is the best shade grass of all those grown. True fine leaf fescues such as sheep’s fescue, hard fescue, and creeping red fescue are actually better adapted to shade than tall fescue, but they have difficulty surviving Kansas summers. It might be better to say that tall fescue is the best shade grass adapted to Kansas conditions. Although tall fescue is our best shade grass, that does not mean that tall fescue is all that good in the shade. Large trees that produce deep shade will not allow tall fescue to survive over the long term. I say “over the long term” because fall-planted cool-season grasses will often do well under shade trees through the fall and spring when there is less leaf cover and growing conditions are better (cooler and moister) than in the summer. We often see people plant tall fescue in the shade each fall and then wonder what happens the following summer. The answer is stress from multiple fronts. Sunlight that passes through the leaves of trees has had most of the “good” light that drives photosynthesis stripped out. The grass struggles to make the food it needs for survival and growth. When this poor diet is combined with the additional stresses of drought and heat, tall fescue is unable to survive.

So, what should you do if you have too much shade for your turf? You have three choices. Reduce the shade by pruning up the lower branches of your trees so more early and late sun reaches the turf. This is not practical with many trees because it can destroy the desired shape. A second option is to plant a groundcover that is well-adapted to shady sites such as periwinkle or English ivy. Another solution would be to mulch the area under the tree.