Dethatching Zoysia Grass Lawns

Thatch is the worst potential problem associated with a zoysia grass lawn and can be especially bothersome on the faster growing cultivars. Thatch is a collection of dead plant parts like stems and grass clippings that collect on the soil surface. Thatch is generally a problem when it becomes thicker than .5 inches and grass roots begin to grow into it as if it was soil. Thatch dries very quickly in hot summer conditions, and grass roots growing in it are much more likely to have problems from drought. In addition, thatch often encourages insect and disease problems.

The best way to control thatch in zoysia grass is to prevent it. There are a few ways to do this. Begin each year with a clean slate by mowing your dormant lawn and raking/removing as much of the dead top growth as possible (see mowing). Bag your clippings during the growing season, use slow release fertilizers and fertilize moderately. Last you can use Lazyman Gold to aerate and thatch your lawn which will naturally keep your soil porous and your thatch to a minimum.

If your zoysia grass accumulates a thatch layer greater than .5 inches of thatch during the growing season, you may need to mechanically dethatch. Vertical mowing (dethatching) is tricky and should be performed with extreme care. Do not cut too deeply or make more than one pass over the entire lawn. In addition, never us a vertical mower during periods of drought. After vertical mowing, rake and remove all thatch from the zoysia grass surface.

You may be tempted to burn your zoysia grass during the winter to remove the thatch and dead top growth. This is not recommended. Fire can damage zoysia grass rhizomes and stolons and kill areas of your zoysia grass lawn. Zoysia grass is very slow to re-grow, so these dead patches can ruin an otherwise beautiful zoysia grass lawn. Besides, grass fires move quickly and are extremely dangerous.