How to get moss off a concrete patio
Image by Andrew Fogg; Flickr.
Moss grows in clumps or mats in moist, shady habitats. Mosses reproduce by throwing off spores. Some people buy moss for their concrete or stone patios in order to give them an aged look. Others cannot abide moss and do everything possible to get rid of it. Both points of view are understandable.
Moss does give an air of ancient respectability. And it does create a significant safety hazard because it is slippery. If you want to eliminate moss from your concrete or stone patio, try these solutions.
Mix 4.5 litres of white vinegar in a bucket with 1 tbsp of washing-up liquid. Use an old mop, a long-handled brush or a large sponge to wipe down the patio with the solution. The moss should be gone in a couple of days, though a second application may be necessary. Repeat the process if the moss comes back.
Splash boiling water over the patio. Be careful not to splash the water from the pot on yourself. The hot water will kill the moss. Like vinegar and dishwashing liquid, boiling water will also call kill other plants it touches, so don't splash too far.
Scrub the moss away with a long-handled stiff brush. Since moss does not have roots, it will come away quite easily. For a little more efficacy, add 1 part chlorine bleach to 5 parts water and scrub the solution on the patio as you are scrubbing away the moss. You can also add a little washing powder to the water-bleach combination.
Remove the moss with a pressure washer or power sprayer if it covers an area too large to comfortably treat by hand. Practice somewhere where nothing is growing first. A mishandled pressure washer can tear your garden and decorative pavers apart.
Apply a commercial herbicide. There are dozens on the market and most of them will get rid of moss. Apply according to the manufacturer's directions if none of the less environmentally harmful strategies work. Test the commercial herbicide on a small area of your patio before you apply it everywhere. Some herbicides will discolour concrete. Most likely, you will not need to use the commercial products in any case.