Got Shade? Expect to have Moss this Spring
We are observing an increased percentage of moss in lawns this month thanks to the mild winter. As explained below, high concentrations of moss in turf can be caused by one or a combination of several factors impacting your lawn. If you really want to eradicate moss you have to find out the actual problem that is causing it, rather than just treating it. The reasons are various, but not too difficult to isolate.
Generally, turf that is well maintained will have fewer moss issues. Moss forms in turf because of one or several of the causes outlined below:
- Shaded Lawns - overhanging trees or large shrubs; turf growing on the north side of a structure, this is the most common reason for moss. Particularly when one of the following also occurs
- Waterlogging - in winter or summer
- Acid soil - low pH
- Mowing too close - a common cause, for it weakens the grass - allowing moss to take hold. We recommend mowing at 3"
- Drought - if severe enough to harm or kill the grass. Not to be confused with a bit of summer-browning
- Sandy - free-draining soils. This can weaken the grass and allow moss to take over. Some mosses are quite happy in these conditions
- Compaction - continued use by children and pets
Moss can be temporarily controlled with Iron Sulfate applied as a liquid or granular but will only kill off the current growth. The aim should be to rectify the cause. Carry out a soil test at some stage to assess the acidity of the soil. If in need of adjustment, then lime can be applied.
- Determine if there are areas of dense to moderate shade in your lawn, and try to minimize this by removing or cutting back the trees or shrubs if possible. Consider eliminating turf under large trees and planting shade tolerant plants
- Apply a Ferrous Sulfate based moss-killer to the affected area
- Apply a lawn fertilizer routinely to strengthen and improve turf density
- Mow the lawn properly, regularly, throughout the summer - NOT too short
- Keep the lawn well- watered in drought conditions to allow the new grass to keep growing
- Fall - aerate the lawn, apply top dressing at this time if the lawn is either uneven, or in need of organic matter particularly useful on weak sandy soils
If by the autumn, your lawn is growing well, then most if not all of the moss in your lawn will have been controlled. Further spot treatments may be needed or maybe even a full treatment for most lawns again the following season.
Moss isn't necessarily bad
There are several species of moss that thrive on Cape Cod. Dry soil is susceptible to moss which tend to grow in upright habit with small leaves and do not spread much. Damp, compacted and waterlogged lawns usually results in mosses that have a creeping habit. If you are battling moss in a wet / shady spot on your property you may consider giving in and let the moss be. Add other shade loving perennials and ferns to create an interesting, carefree shade garden.