Thatch and Power Raking

Considering all of the questions we have had recently about thatch and power raking I figured we should throw some info out there…

Thatch is an organic layer of material that is immediately above the soil and below the grass shoots. The first thing to keep in mind about thatch is that all home turfs have it. In fact, there are benefits of a small amount of thatch, .5 inch or less, (Christians, 2011). Most notably, it is believed thatch insulates the soil from heat stress in mid summer, and may help battle weed infestations. Another thing to understand, most of us do not have a thatch problem.

Thatch is typically caused when new grass is growing faster than microbial life can break it down. So, the first thing to ensure is that you’re not overusing fertilizer. Excessive nitrogen, the first number on the fertilizer bag, is responsible for shoot growth. Keep in mind the maximum number of fertilizations per season is 5, and we recommend a maximum of 4. Make sure you’re putting down 1 lb. of nitrogen / 1000 sq. ft. or less, otherwise you will create excessive shoot growth. Additionally, there might be a lack of microorganisms in your soil, therefore not capable of breaking down the organic material. Try switching to an organic fertilizer, such as Richlawn or Colorado’s Choice. Another option is topdressing the soil with a nutrient and microbial rich topsoil. Also, don’t over water. We shouldn’t have an issue with this for the summer, considering regulations. But, keep in mind, too much water can choke out the microbial life. They need oxygen as well, not to be swimming.

Now, power raking. We do not power rake, and we never will. There is overwhelming evidence showing that power raking removes more living material than dead material, and therefore is more harmful to the turf. Period. It is said that if you have thatch problems, try the remedies above, basically changing your ‘management’ approach. If you legitimately have thatch, the best fix is proper, seasonal aeration. This means aerating once in the spring and once in the fall. Aerating pulls plugs up, containing thatch, which can then break down naturally. For proper aeration each piece of turf needs to be aerated over twice, ensuring that plugs pulled are within 2-3 inches of one another. Going over it only once, plugs will be 4 inches apart, not truly helping the situation.

*Christians, Nick E. 2011. Fundamentals of Turfgrass Management, Fourth Edition. pp. 215-218.

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