Hardiness Zone: 10a
Takisha from Pittsburg, CA
It isn't necessary to use coffee grounds more than 1 or 2 times per year on your roses. Any more and you can start to alter the pH too much. To be safe, I would recommend purchasing a simple pH test. These test kits are easy to use, inexpensive and readily available at lawn and garden stores. Performing your own test will not give you the same accurate results you would get from a certified soil-testing lab, but it will give you a good general idea of where your soil lies on the pH scale. Roses (and azaleas and rhododendrons) do prefer acidic soil, but too much acid will kill microorganisms and harm your plants. A few grounds once or twice a year is safe, but unless you have really alkaline soil, I wouldn't apply any more than that without performing a soil test first. Incidentally, I would say the same about applying wood ashes to your soil to make it more alkaline. Use one cup of grounds per bush for each application to give your roses a nice boost.
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By Cathy (Guest Post)09/23/2006
Check the soil acidity first, as roses like a certain level. I have been adding coffee grounds to my roses for several years, whatever is in the refuse container, I just sprinkle it around. The roses seem to enjoy it.
By (Guest Post)08/25/2006
Coffee grounds are exremely acidic. Do not add them to roses. They are best for hydrangeas that you want to have blue flowers and for azaleas. I am waiting for cooler weather to try banana peels for my roses. I read about that on this site, I think. By the way, you just loosen the soil and mix the stuff in with it, near the roots....
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