The KPRC Radio Gardenline Tip By Randy Lemmon For 03-03-05 Printer-Friendly Version
De-Thatch And Other Interesting Stuff...
Randy, do I need to DE-THATCH my grass?
Randy, how often should I have my turf AERATED?
Randy, when do I SCALP my lawn?
I'm getting inundated with versions of these questions both on and off the air as of recently. And while we did an email tip sheet just a few weeks ago on DE-THATCHING alone, I'm still getting lots of questions about the differences between DE-THATCHING & AERATION & SCALPING, and are they one-in-the-same? Here's the link to the tip sheet from February that was dedicated totally to debunking the DE-THATCHING myth.
< http://kprcradio.com/pages/listenernewsletter/GardenTalk_01-27-05.htm >
Anyway, here's the whole story on DETHATCHING/AERATION/SCALPING!
First, let's get the record straight on "DE-THATCHING" for the Houston area. "Thatch build-up" has risen to mythical proportions in recent years. Unlike parts of the Midwest and Northeast, we just don't have a serious Thatch Problem. If your mulching mower is pulverizing the grass small enough, you shouldn't have a thatch build up. Those that still bag their grass clippings (I don't understand that, and it's a huge soap box issue for me, but we'll leave that discussion for another day) absolutely should have nothing to worry about. Even then, a once-a-year AERATION also helps to prevent a thatch build up. By definition, THATCH occurs when our organic material from the mulching process is produced faster than it can decompose.
A certain amount of thatch is desirable, because it works as a cushion for high traffic areas and an insulator from extreme temperatures and reduces water evaporation. Finally, if you actually used a DE-THATCHER on St. Augustine and Bermuda lawns, they'll look horrible, and quite possible damage them to a point of no return. The key to finding out if you have too much thatch is to dig out a small square of grass with dirt, roots and all. Then look at the layer of organic material between the grass blades and the soil line. If it's thicker than one-half inch, then an AERATION is probably in order. (By the way - If someone has told you that you have a THATCH PROBLEM, my bet is they were also trying to sell you some product or service.)
So, let's focus in on AERATION and SCALPING. Many people may actually be unfamiliar with what we call SCALPING. The scalping is usually the first mowing of the spring, in which we lower the mower by an inch or so below the normal setting. And this is the one time of the year I actually encourage the use of a bagging lawn mower. Because, by lower the mower and using the bagger, you're vacuuming up all the debris and dead grass from the winter. Not only does scalping remove the dead to dormant grass, but it opens the roots and soil to fresh air and sunshine. WARNING: If you scalp too soon into the season, and we suffer a freeze, the root system of the grass is extremely vulnerable. That's why we SCALP only when we are certain there are no more freezes heading our way. Finally, if you don't have a lot of dead material in the lawn, you don't really need to SCALP, instead you probably just need to AERATE.
Thus, we are back to AERATION (Which by the way is pronounced AIR-A-Shun, not Airy-a-shun, another soap box issue for another time). You can rent one, hire a company or chemically do it yourself. Companies that you hire, normally use a Core Aeration Machine that pulls plugs out of the ground, which in my view, is the best kind of Aeration. There are some Aerators that you can rent, that poke holes in the ground. And then, there's the do-it-yourself Microbial/Soil Activator Aeration. This is using any of the liquid or granular treatments that organically treat the soil. This is a gradual process and needs to be done consistently for several months.
If you've never tried any of the treatments mentioned above - AERATION, SCALPING, MICROBE TREATMENT, SOIL ACTIVATOR etc. - try a combination of any or all of the above, especially if you know you have compacted soil.
Until next issue, here's to
Great Gardening from the GardenLine, heard
exclusively weekend mornings from 8 to noon
on Talkradio 950 KPRC.