Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover Multi-Surface Cleaner, Ready to Use, 64 Ounce

I have used Wet & Forget for three years to protect the screens in my screen porch from developing moss, mildew, and that Green Gunk. Before using it, I had to powerwash the screens from the outside, which is not simple. Now, after my annual powerwash of the porch screen room and screens from the inside, which is simple, I use a mop-like tool to wet the screens on the outside, which is also simple. Spraying doesn't work well because the product goes through the screen into the screen room and takes a lot of product. Using a mop-like thing on the end of a pole is a quick, effective, easy job. It really, really works to stop the Green Gunk, and my screen porch is mostly North facing. Cheap, effective, simple to put on. Oh yeah, I called the company before using the first time to ask if the produce would harm or deteriorate the nylon screen. Nope.

It worked! I had a lot of algae on a shady back deck. I read wet and forget would work, but it would take a long time, maybe even weeks. But in my case the algae was literally gone the next day after application. I'm interested to see if it also helps get rid of some other unidentified buildup on the deck railing, but that would just be a bonus at this point. I thoroughly saturated the railing on a somewhat cloudy day with no wind or rain. Maybe 12 hours later the green on my deck was completely gone. It did rain a little a few days later which I think is supposed to help reactivate the product or something, but by then all of the algae was already gone. The sprayer was easy to put together and easy to use. It's probably a little less economical but I like that this version was premixed so I didn't have to measure or add water.

Does as advertised. Gets siding clear. I live on a lot of land. I did notice that earthworms came to the surface and writhed in agony in areas where I applied this. Other insects seemed to be extremely bothered, most fleeing even light applications. I'm no naturalist, and I seemingly have enough gross worms to seemingly repopulate the world, even after application of Wet and Forget. But, maybe keep your cats and dogs away for a few days after application.

I did a test — see photo — plastic fence was moldy after several years, so I sprayed half the panels with this product (on the right) and sprayed with water as a control (on the left). After two weeks, the panels I had sprayed were quite clean, as you can see in the photo. (Photo was taken a few months later, in winter, of two panels.) I have had similarly strikingly good results on the vinyl siding of my house. Note, that along with mold there is often trapped dirt. This product kills the green mold, but a bit of dirt sometimes remains, so results do not always look perfect, but the mold is gone and seems to stay gone. I have been very careful, as instructions say, not to spray on any plants, and to wear gloves, and not to breathe it in. When I researched this, I read that this is the same anti-mold chemical that hospitals use. And indeed, having worked in a hospital, this is what some of their chemicals smell like (not alcohol, a different smell.) Don’t use it if it will rain in a day or two; it must dry onto the surface you are cleaning. You can use it in cold weather, but not freezing cold. The product came with a detached sprayer, so I found myself lugging the bottle in one hand and spraying with the other hand, which was perfect. I much prefer doing that rather than buying the version that attaches to your hose, which does not seem as precise a delivery mechanism. Product also warns not to spray on anything that little kids will be playing on, or around, e.g. kids’ toys I suppose or jungle gyms that might get this on their hands and then into their mouths. I would also keep it away from any gardening areas, since molds and fungus can be an important contributor to soil fertility. The reason I wanted to use this method rather than power washing is largely because power washing is known to force water in between the cracks of vinyl siding and mess up the interior of houses. I didn’t want to risk that. But, on the other hand, this certainly is a strong chemical.

I read all the reviews, I know someone that used this and said it works, well it did not work for me, I recently bought a villa, the front had concrete edging around the mulch, it was covered in black mold and mildew, I used the entire bottle, read the instructions and followed them, I even tried brushing the edging, nothing worked and they are just as black as when I first started. I would not recommend this as it did not work for me.

We live in an area where the front yard gets a lot of shade and we are 'blessed' with algae, moss, mold, and mildew problems in those areas that need to be treated every now and then. A spray and forget product is the ideal solution for treatment vs anything that needs to have a scrubbing follow up. This seemed like it might do that from some of the reviews, but not so much. Application. The product is designed to be generously spread over the effected area using the included pump handle. While this would probably be effective for spot treatments, any larger area requires you to repeatedly pull the spray pump handle and soak one spot at a time over the entire area you want to cover. This becomes repetitive and painful if trying to do in in one go. Maybe transferring it to your pump sprayer would make it easier, but they get a 1-star as is it set up now. The coverage also leaves a lot to be desired. I was able to treat only a few sidewalk sections and a small part of the porch during this test run. Effectiveness. Half credit here. The product is designed to work its magic and then let rain and wind remove the remains for your cleanup. I sprayed on a Friday and the end of the next week we had our first wind/rain event. The mildewy green on the sidewalk sections did almost have most of their green topcoat cleared up in the first few days, but it was not 100% effective. The walk pictures here show the before and after shots and this was where it did the most good. The porch shots show the darker mold coverage that looking now it claims will take several months to remove. That's just not effective. Going out during the rain, I was able to foot scrub one of the darker spots that looks a little lighter in the after photo, but the rain poring on it was not cleaning it at all. So the Forget part of the spray and forget may work, but I can't have a product that takes months to finish. As for moss, the stonework around the flowerbed in the before and after shots show basically no effect whatsoever. The moss I test sprayed in the landscape timber shot does show some minor yellowing on one cluster, but the bulk of that piece and the remainder of the moss along it is still growing strong. Spraying the porch brickwork also yielded minimal results. So, overall, if you have the light green algae/mildewy coating on a relatively non-porous sidewalk, this is probably a solution that would work for you as it was effective for that limited purpose. Anything tougher I would suggest you pass on this for something stronger.

AMAZING product! I tried everything to get rid of the green algae on my outdoor cushions and nothing worked....until Wet & Forget. I will be a customer for life.

I initially thought I'd need to scrub the tiles and it worked, but it was an unnecessary effort. Just thoroughly spray and let the formula do it's magic. It takes time, but it works and is so much easier.

I have already tried the product. It was good. The mold and algae were slowly disappearing. I will sure order again. Only thing i hope is the seller can lower down the price a bit as it's quite an expensive product.

I was very surprised how well this worked. The side of my house (see red highlight in pic) had algae growing on it. I sprayed on wet & forget and within a few days can see an amazing result. I will definitely buy it again.

Expensive and not able to work as intended. Very disappointed.

I spray Wet & Forget Outdoor on 30th July 2021 on a external wall, the algae disappeared in 1-2 weeks. now (19th August 2021) there are some black stains left, I am not sure if those stains are dead algae, mold, or mildew, need to wait for a few months to see the effectiveness since the wall was sprayed 20 days only.