I have problem with moss growing in my lawn underneath some cedar trees. How should I handle this problem?
There are several causes of moss in lawns and garden areas including: decreased soil fertility, heavy shade, compacted or wet soils, a thick thatch layer in lawns and acidic soils. Once you have isolated the problem/s they are relatively easy to fix.
Amending garden soils with well rotted, organic compost and applying mulch can improve garden bed fertility. Lawns can be fertilized early spring with a balanced lawn fertilizer, such as a 14-4-8 blend. Look for these numbers on the packaging or ask for assistance at your garden centre. These numbers show the amount of Nitrogen, Phosphate and Potassium in the mixture. Towards the end of summer, you can add a high nitrogen blend to your lawn e.g. 23-3-23. This will encourage root growth and green up your lawn. Make sure to irrigate your lawn for 20 or 30 minutes, twice a week, early in the morning (before the sun gets too hot) to prevent the fertilizer from chemically burning the lawn.
If your soil is compacted or poorly drained, aeration will help. Dig a garden fork into the soil, at regular intervals, where the moss is a problem in your garden bed or use an aerator on your lawn. This helps to increase the amount of air getting to the root zone, which will increase microbial activity and accelerate the rate that organic matter is broken down, such as thatch in lawns. If your lawn has the moss problem, check to see if there is a build up of thatch. If you have more than 2 inches of thatch (dead grass) accumulating at the base of your lawn, dethatch with a stiff rake. If its a large lawn you may wish to rent a dethatcher to save your back. Dethatching should be done early spring or early fall to reduce the chance of weed outbreaks. This helps to expose your young blades of grass to water, air and light which will allow it to thicken up fill in the patches that are now taken up with moss. Healthy lawns don’t usually have moss problems.
If your moss covered area is very shady, you may wish to thin the tree or shrub canopy to let in more light.
If you try all of the above to no avail, you can test your soil to see if your pH is low. If this is the case, dolomite added to lawns- according to the manufacturers instructions, will increase the pH. You can buy this at your garden centre. Take care not to spread it on pathways as it contains ferrous sulphate which can leave rusty stains on hardscaping.
You may wish to refer to an answer to moss problems previously posted on our web site here. Good luck.