Baking Soda, a Reprise
I lifted this from an article I wrote. You might find it interesting:
"What was really outstanding about Jan's rose fields were that they were only sprayed every week to ten days with feed-grade baking soda (finer than the kitchen variety stuff and, therefore, dissolves easier) and were absolutely clean! No rust, mildew, blackspot, aphids nor downy mildew! This last is a genuine fall-off-your-chair surprise. This time of year, baking soda really proves itself. His treatment works out to 8 grams (1 teaspoon) baking soda to 1 L water and 3 drops of liquid soap4. With so many blooms on the plants in the field, I asked Jan about nipping his roses in the bud to increase the bushiness of his crop, as Chris Pieper does on his highly automated farm outside London, ON. Jan said that it didn't seem to matter much. I wonder if that has to do with the considerably longer growing season on the West Coast (Cnd zone 8 vs 6b; US 8 vs 5), but Jan feels it is a very dubious proposition labourwise, and doing it by machine, doesn't take into account roses growing to different heights. Cutting leaves is cutting the lungs of the plant away. He does not think it is done in Holland except for tulips."
The complete article: http://www3.sympatico.ca/wm.saundersrose/articles/Visit.html