Moss may lend a touch of wisdom and age to a Japanese garden, but in a lush lawn, it means nothing but trouble. Moss will compete with your turf grass for water and nutrients and in no time, you’ll have an unsightly lawn.
There are a few things you can do to control moss. You can rake it out, aerate and thatch your lawn and of course, use a moss killer.
The best time to apply moss killer on UK lawns is in spring and autumn. The days are warm and wet, and moss is actively spreading in your lawn. For quick and effective results, mow your grass, identify the moss-wrecked areas, spread the moss killer and finally, rake away dead moss.
When does moss appear?
Moss is rather opportunistic. It will appear on your lawn whenever the conditions are ideal. Spring or autumn, the season doesn’t really matter.
Most varieties of moss enjoy shady lawns with inadequate sunlight. Damp, compacted soil, regular rainfall and poor drainage can also promote moss growth. Soon, your turf grass will seem shy about growing lush and full and a carpet of moss will overwhelm your lawn.
But where does moss come from?
Unlike seed-bearing plants, moss has spores, tiny cells that can reproduce on their own. These spores are carried by the wind from one place to another. If your lawn is damp and shady, these spores will find the perfect home to germinate and spread.
Image credit: @hampshirelawncraft
When to put moss killer on your lawn
To kill moss, ensure that it is actively growing. Late spring and early autumn are the best times to apply a moss killer. That’s when the weather is gentle and warm, but not hot.
There are many different types of moss killers available on the market. These generally come in liquid or granular forms. Note that while these will kill the moss, they won’t address the root cause of the moss problem.
Let’s take a look at some common moss killers and the right time to apply them.
- Copper sulphate: Copper-containing moss killers will kill moss on contact. Spray it over moss-affected areas in spring or autumn. Copper sulphate can stain concrete slabs and tiles around your lawn so be careful during application.
- Iron sulphate: Lawn moss killer with iron sulphate is often available in granular form. It’s very effective and brings results in 4 to 5 days. But note that iron sulphate is best applied in humid conditions, preferably after rainfall. Be careful not to add too much iron sulphate.
- Ammonium sulphate: Ammonium sulphate moss killers burn the moss. They should be applied during colder days, like early spring or late autumn. Avoid watering after application.
Next, follow these simple moss treatment methods in spring and autumn for optimal results:
Spring moss treatment:
- In late March, apply moss killer when the weather is warm.
- In April, proceed to rake out dead moss.
- Overseed the areas where the grass is thinning and top-dress if necessary.
Image credit: @joeslawncareltd
Autumn moss treatment:
- In mid to late September, apply moss killer to your lawn.
- Once the moss has blackened, scarify the lawn.
- Aerate to fix compaction.
- Lightly overseed and top-dress your lawn
Topdress your lawn in autumn to get it winter-ready. Image credit: @rasennerd
How to apply moss killer
You can apply moss killer in a single step. But you need to prepare your lawn to ensure that the formula reaches the moss-afflicted areas. Afterwards, rake away dead moss and top dress if needed.
Step 1 – Mow your lawn
Mosses hide beneath your lawn grass. To expose them, it’s important to mow your lawn before applying a moss killer. This will also allow the moss killer to reach the soil and work effectively.
If mowing in spring, keep the grass short. In autumn, raise the height of your mower blades since grass growth is slow. Remove the clippings and leave your lawn untouched for a week or two.
Step 2 – Determine the mossy area
You don’t have to apply moss killer on your entire lawn, apply it only over the parts covered in moss. Doing so has two benefits:
One, you won’t be overusing the moss killer in areas that don’t need it. And two, you can easily determine the quantity you will require.
Step 3 – Apply the moss killer
First, read the product label for instructions. This includes the concentration specified, watering needs, weather conditions and other important information.
If you’re using a liquid moss killer, simply spray it over the moss and soak it well. If you’re using granular or powdered killers, use a push-along spreader or manually spread them by hand. Water afterwards as directed.
Tip: Be careful not to apply too much moss killer. It can burn or even kill your lawn grass.
Step 4 – Rake away dead moss
In a week or two, you should see the effects of moss killer on your lawn. The moss will dry out, eventually turning black. At this point, you can rake it out using a spring-tine rake or lawn scarifier.
The effect of iron sulphate on moss. Image credit: @vines_gardenservices
Top-dress your lawn with a mix of sand and compost. This will help the grass to grow stronger roots. You can also overseed thinning lawn patches 4 to 6 weeks after moss killer use.
How to get rid of moss
Preventing moss from returning requires more than just applying a moss killer on the lawn. You’ll have to address the reason why moss is so fond of your lawn.
If your lawn doesn’t get enough sunlight, trim tree branches around it for more direct sunlight. Feed your lawn regularly and keep the grass healthy to encourage deep rooting. Also, improve soil drainage and compaction.
We’ve devoted an entire post to this common problem. Read more about how to get rid of moss in lawn.
Say goodbye to moss
Moss in the lawn is not just unsightly. It also steals nutrients, leaving your turf grass undernourished.
But you can count on moss killers. Available in liquid and granular forms, these products are effective and easy to use. In most cases, you’ll see results within a week.
Moss killers blacken the moss and dry it out. This makes it easy to rake the moss and clear your lawn. Put dead moss in your compost heap to make the best out of the waste.
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