What Is Thatch?
Thatch is made up of tightly intertwined pieces of stems, roots, and debris that are slow to decay because of high cellulose content. It builds up in a layer between the grass blades and the surface of the soil. If the thatch gets too thick and/or the soil gets compacted, roots may start growing into the thatch, and since thatch does not hold much water, the turf becomes increasingly prone to drought stress.
What Causes Thatch Problems?
Thatch buildup is due to over-fertilization, over-watering, and/or soil compaction. In the case of over-fertilization and over-watering, the growth of the lawn out paces microbs breaking down old organic material. Thatch problems are seen more in lawns that are over maintained or have high foot trafic.
How Much Is Too Much?
Thatch isn’t always a bad thing. In fact, a layer of thatch between 1/4″ and 1/2″ thick is beneficial. It provides a cushion against the soil surface and helps to reduce drastic fluctuations in soil temperature.
Thatch doesn’t become a problem until it gets over 1/2″ thick. Too much thatch restricts water and air movement, reduces fertilizer and pesticide response, increases disease problems and grub activity, and may result in the grass taking root in the thatch itself.
How Do I Get Rid Of It?
If you get to the point where you have a real problem with thatch build up, you may need to use a dethatcher to help get rid of excess thatch buildup.
When dethatching, you only need to dethatch part way into the layer of thatch. You don’t have to remove all the thatch. If you do remove all or most of the thatch, reseeding may be in order.
If the thatch gets really thick, say thicker than 1″, you may even use a sod cutter if you like to remove it. In this situation, you’d want to set the sod cutter to a very shallow depth so you don’t take off more than you need too. After doing this you will definatly need to reseed. Using a sod cutter would be a very drastic measure taken only because dethatching alone wouldn’t be enough.
How do I prevent it?
Probably the best way to prevent thatch is to not over-fertilize or over-water your lawn. Also make sure that you aerate on a regular basis to keep the ground from compacting too much. Most lawns only need to be aerated once per year. Some lawns may need to be aerated more often than that.