What is lawn thatch?
Lawn thatch is an accumulation of tightly meshed dead and living stems and roots that build up between the zone of green vegetation and the soil surface. A less than 1/2 inch thatch accumulation is usually not detrimental to the lawn, but when more than 1/2 inch thatch accumulates, problems may occur. A thick layer of thatch may cause a shallow root system with roots growing only in the thatch, increased disease and insect attack, increased scalping from mowing, dry spots in the lawn, and reduced tolerance to environmental stresses.

Thatch develops when the rate of organic matter accumulation exceeds the decomposition rate. Cultural or environmental factors that stimulate growth or impair thatch decomposition will promote thatch accumulation.

What Factors Contribute to Excessive Lawn Thatch?
• Acidic soils with pH below 6, which reduces earthworm, insect, and microorganism activity
• Compacted soils with restricted oxygen levels which impair activity of decomposing organisms.
• Excessive nitrogen or watering that stimulates shoot growth.
• Infrequent mowing or excessively high mowing height
• Use of more vigorous growing turf grass varieties

Is my lawn susceptible to Thatch?
High maintenance lawns may require thatch control treatments annually due to vigorous growth while low maintenance lawns may never develop an excessive amount of thatch.