How to Mix Zinc Sulfate Powder to Kill Moss

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Things You'll Need

  • Gloves

  • Breathing mask

  • Safety glasses

  • 5-gallon bucket

  • Zinc sulfate powder

  • Warm water

  • Painter's stir sticks

  • Garden hose

  • Garden sprayer


Discourage moss growth by pruning back tree branches, thus facilitating air circulation over your roof.

Remove as much moss as possible before spraying a zinc sulfate solution on the shingles.

Place buckets under your downspouts to capture excess solution. Dispose of the runoff according to the manufacturer's directions.


If exposed to zinc sulfate powder by swallowing, inhaling or getting it in your eyes, contact Poison Control and your doctor immediately. Follow the first aid procedures listed on the package directions.

Avoid climbing on the roof if possible. Wet roofs may be slick; do not risk falling off your roof.

Do not use zinc sulfate on roofs that have copper gutters and downspouts. The zinc will react with the copper.

Protect your plants and shrubbery from over-spray with plastic sheeting or tarps.

Clean all supplies with soap and water according to the manufacturer's directions.

Keep out of reach of children and pets.

Wood shingles are a favorite place for moss to grow.

Removing unsightly moss from your roof is an important part of home maintenance. Moss is more than just ugly — it can dam and divert water runoff, causing water to leak into your home. However, while mixing and spraying a zinc sulfate solution, you must be careful to protect the surrounding vegetation and watershed. Zinc sulfate is toxic to fish and other invertebrates.


Step 1

Put on safety gear, including work gloves, a breathing mask and safety glasses.

Step 2

Pour 3 gallons of warm water in a plastic 5-gallon bucket. Do not use metal — the zinc may react with metal items.

Step 3

Add 1-1/2 lbs. of zinc sulfate powder slowly to the water to avoid dispersing the powder in the air. Stir it with a disposable painter's stick to mix it thoroughly.

Step 4

Pour the zinc sulfate solution into a garden sprayer. Attach a garden hose to the sprayer and apply it to the roof.


references & resources

Ruth de Jauregui

Ruth de Jauregui

With degrees in fine and commercial art and Spanish, Ruth de Jauregui is an old-school graphic artist, book designer and published author. De Jauregui authored 50 Fabulous Tomatoes for Your Garden, available as an ebook. She enthusiastically pursues creative and community interests, including gardening, home improvement and social issues.