Coffee Grounds for Roses?

Question:

How much and how often do I use coffee grounds for my roses?

Hardiness Zone: 10a

Takisha from Pittsburg, CA

Answer:

Takisha,

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.

Ellen