What Causes Spongy Grass Seed Development?

Thatch

• Thatch is the primary cause of sponginess in grass. Thatch is a layer of partially decomposed grass, leaves or stems that sits above the soil. Thatch is almost always present in lawns, but if it gets to be longer than ½ inch, it will start to hold the water and fertilizer away from the roots. Walking on thatch also causes that characteristic spongy texture as you walk across your grass.

Thick Soil

• Thicker soils, such as clay soil, can also cause spongy grass. These soils absorb water and fertilizer very slowly, like water draining down a clogged drain. This slow process will keep water and food on the surface and will make grass feel softer and wetter to the touch.

Weeds

• Weeds are a constant problem for lawns, and while they are not the main cause of spongy texture and reaction in grass, they can certainly play a role. Aside from looking horrible, weeds also absorb food and water that should otherwise go to your grass. This can cause water and food to be absorbed as soon as it hits the grass, instead of sinking deep into the roots where it is needed.

Solution

• The solution depends on your problem. Renting an aerator to run over your lawn will punch small holes in thick soil and can also break up some thatch. Treat weeds with herbicides; make sure you know what type of weed you have before you decide on a treatment, since different weeds respond differently to different chemicals. As for thatch, using a power mower, which is like a mechanical rake, will break up the thatch. Using a regular garden rake will work for smaller thatch problems, but this can be back-breaking work if the thatch is significantly thicker than ½ inch. Finally, if your grass has grown so weak and spongy that it is unusable, you can remove the sod or reseed the entire area.