Q. Our backyard block wall has some white stains on it. These appear where the sprinkler water hits the wall and I want to remove them. I have read on-line to use things like diluted muriatic acid, but I don't want to kill the plants my wife has throughout her garden. How can I clean the stains, and can I treat the walls to protect from more stains forming
|Salt deposit on slumpstone wall when plants are being|
irrigated by bubblers. Salt in the water is carried
up the wall where it evaporates, leaving behind the salts.
The other side of the wall does not have sprinklers
hitting it either.
A. These are salts remaining from either those sprinklers or water from the soil wicking up the wall. Our soils contain quite a bit of salt as well as our water. Water coming from Lake Mead carries about 1 ton of salts for every 326,000 gallons. It sounds fairly dilute but it is not.
Our soils vary much more in salt and can be removed by leaching. The salt in the water of course is consistent. The combination of the two can mean some pretty high salt levels. Salt dissolves readily in water and when the water evaporates from the wall, it leaves the salt behind. These are probably the salt deposits you're seeing on the wall. Even drip irrigation can cause problems like this since the water can wick through and into porous surfaces.
You don't have to use muriatic acid but you can use and acid, even vinegar to help remove it. The major concern with plants is having the acid fall on foliage. This will damage the plant. Of course the best way to prevent it is to not use overhead irrigation.In the case of drip irrigation, put the emitters on the opposite side of the plant from the wall, not next to the wall. Perhaps there is a treatment to the wall that could prevent this from happening. I don't know of any.