Here in the PNW we have all of the ingredients to brow and sustain moss year-round. What causes moss to grow? Moisture and Shade (and the combination of both) are key factors in creating a place moss likes to thrive. Lack of drainage, and over watering can also cause moss to take root and set up shop. Some tips to help you reduce the chances of moss growing are:
- Trim trees, bushes and shrubs that are causing excess shade. This can over your roof or in your lawn.
- Add a French Drain to pull away excess moisture and ensure moisture does not collect in your lawn inviting moss.
- Fertilize and seed your lawn. A good thick healthy turf will prevent moss from growing.
- Mosses do not force grasses out. They take over areas where grasses have failed. Healthy strong grasses keep mosses away.
- Grasses mowed too short, allow moss to move in, once you start treating the moss, try raising the cutting height of your mower.
But if you already have some moss and need to get rid of it, there are some options. Liquid and granular “Moss Out” options such as the “Lilly Miller” brand of “Moss Out” are great options. There are options specific for lawns and for roofs. It is important to note that the options for lawns should not be used anywhere else. They will stain concrete, fencing and your roof. While the stain can be removed, it’s time consuming will cost you some more money. It’s best to read the labels and pick the options suited to your needs.
Both Lawn and Roof options come in granular and liquid formulations. Most people find that the liquid formulations are the easiest to apply and work the fastest. The Lilly Miller brand offers a bottle with a hose end attachment. This is ideal as it does all the measuring for you and takes the guesswork out of the process. Simply attach your hose to the bottle and open the valve and spray the affected area(s). Within just minuets you’ll see the moss start to change color and die off. Its best to plan this when you’ll have some dry weather ahead. After spraying your lawn, give it two days and you’ll see a very noticeable difference. All the moss will have died off and turned brown and / or black. Now it’s time to rake out all the dead moss. You can use a hand rake, a thatching rake or even a power rake that you can rent from your local tool rental facility.
Depending on how much miss you had to start with, you may be shocked to see so much bare space in your lawn. After the moss is gone, you’ll want to seed your lawn. So, plan ahead here as well. Make sure that you are ready to seed your lawn, shortly after you remove the moss. If you still have drainage, moisture and shade issues, it will be tough to mitigate future moss growth. But a strong healthy lawn will prevent moss from taking hold. So seeding and fertilizing go hand in hand with Moss removal.
For your roof the process is very similar. Using the sprayer (or granules) cover the affected areas, and let the product do the hard work. Once the on about two days (sometimes less) one the moss is dry and has died, simply use a broom and gently sweep the dead moss from the roof, taking care not to damage any shingles. A side note, the moss killer may be harmful to the plants or lawn below, so if there is a possibility of run off, take steps to cover or protect the area directly below the roofline from drainage / spillage.
Ferrous Sulfate (also know as Iron Sulfate) is also used to kill unwanted moss. Timing is important when using any iron-based moss killers. Late fall and early spring are the best times to apply an iron-based moss killer. Try to do this when there will be two or more days with no precipitation in the forecast after application. A cool day is best for application. Remember to protect the surrounding shrubs, plants and fencing from the iron-based moss killer, and just apply to the affected mossy areas. Low wind is important to prevent unintentional overspray. It is most effective to apply when the moss is moist ad actively growing.
Iron based moss killers are typically safe to use around other established plants, but new grass can be iron-sensitive, and if applied too heavy, even established grasses and plants could be harmed. The iron in these products can permanently stain concrete, brick, and stone. Avoid sidewalks, patios, stone pathways. If you happen to get these products on those surfaces, stop immediately and wash them for the best chance of removing them with minimal to no staining.