Ask the Hort Agent: Wet Lawns

Published 12:00 am Friday, July 26, 2013

Question: What should I do for my lawn under these wet conditions?

Answer: There are several things to consider when faced with waterlogged lawns. First, we will assume your yard is wet this year from excess rain. If your yard is wet most years, then you need to address water flow across your property. Above and underground techniques can be used to keep water from ponding.
The general rule for mowing grass is to wait until the grass dries out. Another general rule for mowing is to cut off one third of the grass blade when mowing. The combination of these rules has been a problem for the last two months. Many people find themselves forced to mow wet grass. Of course this clogs up the mower deck and throws clumps of wet grass onto the lawn.
If your mower is leaving tracks, ruts or throwing up a rooster tail, then the ground is too wet to be mowing. In this situation you wait. Obviously, the grass and weeds keep growing. When it does dry out enough to mow, then be sure to raise the mower deck to accommodate the taller grass. Lower the mower deck every time you mow until you get it back to the required height for the type of grass you are growing. If you do it correctly, you should not have to rake hay after you cut the grass. In other words, there should not be windrows of clumped grass laying in the yard when you finish mowing.
While the grass may be dry enough to mow, the soil may still be very moist. Wet dirt is most susceptible to compaction. Be sure to change your mowing pattern. Do not follow the exact same path when you mow. The mower tires will cause compaction. This is especially true of the new heavier zero turn mowers. While heavy mowers can obviously cause compaction, even a push mower can cause compaction if the same path is followed every time.
Resist the urge to fertilize. The only grass that requires nitrogen in late July or early August is Bermuda. Unfortunately, this type of grass does the worst in wet conditions. If your Bermuda is struggling in the water, do not compound this situation by putting out fertilizer. The other warm season grasses (like centipede, St. Augustine and zoysia) and fescue don’t require fertilizer this time of year. Putting fertilizer on them will only create problems.
For more info about lawn height and mowing, visit http://www.ces.ncsu.edu/depts/hort/consumer/quickref/lawns/mowing.html If you do not have internet access, then call me at 910-893-7530 or email me at gpierce@harnett.org
The wet weather has certainly inspired some backyard mechanics to modify their equipment. The use of “monster mowers” on your lawn will only cause problems that will have to be fixed later. Don’t let your husband talk you into this http://www.youtube.com/watch?v=ZEbvyE3u4SU or http://www.youtube.com/watch?v=dQL1gZodjgs I can assure you this is a lawn killer, not a lawn mower (the guy and the machine) http://www.youtube.com/watch?v=SzpLw15UfFg

Gary Pierce

http://www.harnett.org/coop/horticulture-programs.asp