Removing mold safely from bricks

QUESTION: We have a small, beautiful backyard surrounded by used bricks that I gathered out of a Venice canal years ago. The problem is that due to moisture and shade in the garden, a slippery, black mold develops on some of the bricks. How can I get rid of it without killing nearby plants and lawn?

JOHN SCHACHT

Venice

ANSWER: Scrubbing the mold with a stiff brush and white vinegar diluted about 50% with water will do the trick, according to Jackie Scheidlinger, a landscape designer based in Woodland Hills and a master gardener volunteer with the University of California Cooperative Extension.

If the mold has become thick, use a power washer on the mold, she says. These can be rented by the day at stores that rent garden equipment. You also can hire a power-washing company to come out and do the work for you.

To keep the problem from recurring, Scheidlinger recommends applying the vinegar solution every few months. “It’s like mildew in a shower,” she says. “If you keep up with it, it won’t build up.”

The Common Ground Garden Program at the UC Cooperative Extension helps individuals with gardening questions. A master gardener will answer questions about almost everything -- aphids, composting, weed control. Call (323) 260-3238 or e-mail mglosangeleshelpline @ucdavis.edu.

-- Christy Hobart