Friday, February 06, 2009
Exterminating moss on fescue and bluegrass lawns
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
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Q: Moss that is growing in sections of my bluegrass and fescue lawn. I noticed the moss last year and saw lush patches of moss growing this winter. What is causing the moss and how do I get rid of it?
A: Moss patches should be pulled or raked out of the lawn. Good grass seed should be sown in those bare places and then watered regularly.
Poorly drained, persistently wet soils encourage moss growth and weaken turfgrass growth. Look where water is draining from and why it’s not draining into the soil or off your property. Corrections might involve aiming gutter drain water elsewhere or making slight slopes as needed to channel water out of low lying areas.
Acidic soil conditions will weaken turfgrass and encourage moss growth. The remedy in Southwest Virginia is to make the soil pH between 6.0 and 7.0 with 7.0 being considered neutral. Soil for lawns should be tested every few years. Changing soil pH is a slow process, and it can take many months for a surface applied lime application to raise the soil pH even a little bit.
Medium to dense shade is another possible moss cause. Solutions can be as simple as pruning trees or as living with the fact that the north side of your house will see more shade than sun.
Repeated “scalping” of the turf on uneven lawn terrain hurts the grass and helps moss. Generally, close mowing has the direct affect of injuring or shortening the depth of turf roots. Raise the cutting height on your mower.
Is your soil compacted? If so, it will impede water drainage, limit root depth and reduce the amount of air in the soil. Moss doesn’t mind these problems, but vigorous turfgrass cannot thrive with this kind of environment. Core aerification, also known as “plugging”, can be done in a criss-cross fashion to allow air to enter compacted soil, assist drainage there, and loosen “tight” soil. Core aeration machines can be rented if you want to do this job yourself, or a lawn company can be hired to do the work. Aeration is often a job for the early fall, although some folks aerate compacted areas in the spring if lawn weeds are not numerous.
There are no easy chemical solutions to moss in turf, although you can find some so-called “moss controllers” in garden centers.
If the problems limiting turf growth are not solved, moss will bounce right back following treatment from spores that are already in the soil. The moss is not driving out your turf, but the absence of turf vigor allows the moss to thrive.
