Give Cool-Season Grasses a Boost

Lawn Care: September is here and that means it is prime time to fertilize your tall Fescue or Kentucky bluegrass lawns. If you could only fertilize your cool-season grasses once per year, this would be the best time to do it. These grasses are entering their fall growth cycle as days shorten and temperatures moderate (especially at night). Cool-season grasses naturally thicken up in the fall by tillering (forming new shoots at the base of existing plants) and, for bluegrass, spreading by underground stems called rhizomes. Consequently, September is the most important time to fertilize these grasses. Apply 1 to 1.5 pounds of actual nitrogen per 1,000 square feet. The settings recommended on lawn fertilizer bags usually result in about 1 pound of nitrogen per 1,000 square feet. We recommend a quick-release source of nitrogen at this time. Most fertilizers sold in garden centers and department stores contain either quick-release nitrogen or a mixture of quick- and slow-release. Usually only lawn fertilizers recommended for summer use contain slow-release nitrogen. Any of the others should be quick-release. The second most important fertilization of cool-season grasses also occurs during the fall. A November fertilizer application will help the grass green up earlier next spring and provide the nutrients needed until summer.  It also should be quick-release applied at the rate of 1-pound actual nitrogen per 1,000 square feet.  Power Raking & Core-Aeration: Why Power Rake? It Creates Pockets for Air, Water & Nutrients and 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 vertical mower 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.

TURFGRASS & Little Barley in Lawns: Many people mistake little barley (Hordeum pusillum) for a little foxtail because the foxtail and little barley seedheads are similar. However, little barley is a winter annual that comes up in late September - October and spends the winter as a small plant. It thrives in the cooler spring temperatures, forms seed heads and dies out usually by July. Foxtail, on the other hand, is a summer annual that does well in hot weather. Also, foxtail will not produce seedheads until mid- to late-summer. So, why are we talking about little barley now? Because now is the time to control it for next year. The best control for little barley is a thick lawn that is mowed high enough that sunlight does not hit the soil. Little barley seed will not germinate in such conditions. Overseeding now can thicken up a tall fescue lawn and prevent a little barley infestation. However, if you do not plan to overseed, preemergence herbicides can be used to provide at least partial control of this weed. Labeled specifically for little barley is Surflan. It is also sold under the name of Weed Impede by Monterey Lawn and Garden. Surflan can only be used on warm-season grasses (bermudagrass, buffalograss, zoysiagrass) and tall fescue grown in warm-season areas such as Kansas. However, Dimension (dithiopyr), is labeled for barley (Herodium spp.) which would include little barley and therefore can be used to keep this weed under control. Because little barley is a winter annual, apply the preemergence herbicide now and water in to activate. If overseeding, do not apply any preemergence herbicide as it will interfere with the germination of tall fescue. (Ward Upham) Submitted by Fairie Gardener