Coffee Grounds
Question from Curtis:
We love your book and are encouraging our neighbors to garden organically. I’ve heard many anecdotal stories of coffee grounds helping acidic plants such as blueberries. However, I’ve have not seen a garden book recommend them. I would appreciate your advice.
Answer from Pat:
It is beneficial to throw coffee grounds (and tea leaves also) over the roots of such acid-loving plants as azaleas, camellias, blueberries, and blue hydrangeas. Coffee grounds may also be added to the compost pile or straight into garden soil and count as a nitrogenous material. I believe my organic gardening book mentions coffee grounds as a useful acid amendment to throw over the roots of camellias, but next time I revise it I will be on the lookout for where I mention them.
Hi Pat:
I add coffee grounds to my camellias, blueberries, and hydrangeas. I am nervous about adding as a general soil amendment. Do I need to be concerned about turning soil too acidic via coffee grounds? I live in the Orange County area of Southern California.
-Monty
My advice is to continue putting the coffee grounds on camellias, blueberries and hydrangeas. You could put all you have over the roots of those plants and it would never be too much. One of the great things about coffee grounds and tea leaves also is that they are nitrogenous and thus quickly rot and become part of the soil helping to feed plants and adding to the microbial activity in soil. Coffee grounds are especially beneficial since our imported water with which we irrigate is alkaline. So no need to worry about where else to put them either. You could put your coffee grounds anywhere in the garden and no harm done, except on a plant such as Goji berries, that specifically requires alkaline soil.