Correcting a Runaway Lawn
Or
How to Avoid Scalping

David M. Kopec, Extension Turfgrass Specialist

In last month's newsletter, we discussed scalping, why it is a stress on the lawn, and what to do afterwards.

This issue deals with how to avoid scalped lawn. Here we are talking about a condition where due to unseen weather conditions (rain, etc.) you were not able to mow, and now the lawn is quite high! What can we do to return the lawn to its original height?

It is much easier to do this on bermudagrass, than on cool season grasses. This is because:

(1) Bermudagrass has a fast growth rate, and bermuda
grows back from stolons and rhizomes.

(2) Cool season grasses need much more attention to return to the normal height because they grow from tillers only (ryegrass and tall fescue).

(3) Cool season grassed grow slowly in the summer.

If you return to your lawn after a vacation, a long weekend, or after the rain has stopped (lucky you!), here's how to "get back" to the original mowing height.

Bermudagrass

(2) You can scalp the lawn once (you have permission to do this, once).

(3) The next day you have to mow at the same (original) mowing height.

(4) The next day - - don't mow, apply iron.

(5) The next day don't mow.

(6) The next day, mow again.

After this mow 2-3 times weekly, so you don't remove more than 1/3rd of the foliage. If you find that this is too much work, simply raise the mowing height. Now mow twice weekly versus three times weekly.

Kentucky Bluegrass, Tall Fescue, Ryegrass

Scalping devastates cool season grasses, so here's how to avoid this:

(1) Set the mower to cut about 1/4" to 3/8" off the existing (elevated) height.

The next day, mow the grass at the same height.

(2) The next day, lower the mowing height by another 1/4" to 3/8". Mow in 2 directions.

(3) Mow every other day at this "second height" until the grass is green, even looking, and starts to grow across the lawn without looking spindly.

If you are at the "original" mowing height, you are OK.

(4) If you still need to go lower, then repeat steps 3-4-5 again.

If the grass does not respond to the changes in mowing and looks pale, thin, and weak, you must remain at a raised height until cooler weather occurs later in the late summer or fall.