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Adventures of a balcony gardener
Gardening editor and high-rise dweller Marjorie David chimes in today, with a different perspective from Beth’s ground-level view.
Somehow I thought gardening on a balcony would be different than gardening in the soil. You know, easier. No digging, spraying, weeding. But nature happens, even 16 floors up. In early November, I brought two prized containers of herbs indoors for the winter. One pot contained a handsome sage, the other a large thriving rosemary. Everything appeared to be OK for a couple of weeks. Then one day I noticed that my sage plant had gone from beautiful and bushy to furry and stunted. Leaves were drooping and I found a powdery substance on some of them. Powdery mildew had found its way to my balcony garden. I tried washing the leaves. But soon, the mildew was so pervasive that it coated the stems of the plant. I harvested what clean leaves I could find and disposed of the plant. But I wasn’t quick enough. A few days ago I found telltale signs of mildew on the rosemary, a plant I had started from a cutting last year. Now even some of the stems are coated with mildew.
Powdery mildew is caused by fungi. The spores (produced in the white patches) are blown on the wind (and indoors, by the heating system). The fungi thrive in hot humid conditions (remember that warm humid October?). The diseased leaves that fall into the soil can spread the spores to the soil. And cold winter temperatures will not kill the disease. That’s a very good reason to always use fresh potting mix. (For a good explanation of the disease with photos of mildew-scarred plants, see the Cornell University powdery mildew fact sheet.
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