Caring for Zoysia in Kansas City

Lower lawnmower and scalp the old, dead top growth in late March or early April just as the new growth starts. This will do three things... remove material that would become thatch, reduce the insulating winter protection layer, and allow the soil to warm up quicker to encourage spring greening, and give the lawn a beautiful, solid green color instead of a half green appearance if the dead grass had not been removed.

Fertilize zoysia 2 times a year using a well balanced fertilizer like Fertilome Lawn Food + Iron that will provide 1 pound of actual nitrogen per 1000 sq.ft. with each application. The first application should be in May. The second application should be made in July. Avoid early broadleaf weed sprays on zoysia as it is greening up from dormancy. The weedkiller will slow root growth, spring green-up, and stress the turf.

Zoysia performs best when mowed 1-2 inches high. Most rotary mowers will mow 2 inches high on the middle wheel setting. Mowing lower than this usually scalps and causes damage because our lawns are not billiard table smooth. Reel type mowers can mow at 1 inch without scalping. Remember not to remove more than 1/3 of the green leaf tissue when mowing. Close mowing will slow zoysia thatch accumulation. You can catch the grass clippings and slow the thatch build-up... or you can leave the clippings which will increase thatch build-up. Either way, you will have to dethatch zoysia periodically. Note: leave zoysai tall in the winter to act as insulation.

Zoysia will accumulate thatch which requires maintenance to keep it down to desirable levels. Thatch of 1/4 inch is beneficial. Thatch insulates the roots from temperature extremes, reduces soil erosion, cushions against wear from physical activity, and increases water retention and penetration. Over ½ inch of thatch causes problems. Roots grow in thatch during moist spring and then die during summer when the thatch dries becoming difficult to rewet (hydrophobic). Air/oxygen exchange is also decreased and the turf suffers. Fertilizers are not efficient as they tie up in the thatch layer. Insects proliferate in the thatch environment, while protective insecticides are absorbed by the thatch like a charcoal filter.

There are many ways to keep thatch to a minimum or reduce it. Follow the above scalping, fertilizing, and mowing recommendations to minimize build-up. Reduce thatch by core aerating with a machine that takes out small plugs to temporarily get rid of the layer and allow water, air, fertilizer, and insecticide to move efficiently. The plugs will also help top-dress the turf with soil which will help reduce thatch layer.  At this time is also very beneficial to add Natural Guard Soil Activator to increase the rate of break down and add microbes back into the soil. This can be done monthly! This certainly helps in reducing thatch and also really improves soil texture. Verticutting is the quickest way to reduce thatch to under ½ inch. It is hard on the turf because it physically slices through stems and roots, loosening the thatch for raking. It is also labor intensive. Remember, verticutting should be done when the zoysia will recover the quickest... in late May through August.

Zoysia has several insect pests... chinch bugs, white grubs, and billbug larvae. Apply Hi-Yield Turf Ranger granules in late May and water in lightly. Apply Dylox granules in late July and water in heavily. Merit can be used in place of Dylox as a preventative in June and watered in lightly.

There are several diseases that affect zoysia... Zoysia Patch (Rhizoctonia), Zoysia Decline, Dollar Spot, and Northeast Brown Patch. There are chemical controls, but prevention is the best medicine. Use Fertilome F-Stop to control and kill any disease the zoysia might get. This practice will go a long way in preventing any problems with the zoysia.