I use cocoa shells for mulch. Last season, mold developed on all the areas where I put it down. I used cocoa shells again this year and thus far I have not had the mold appear. What causes this mold? Would it be weather or maybe a “bad” batch of cocoa shells?
According to one of our favorite chocolate empires, Hershey’s, waste shell from the extraction of chocolate from the cocoa bean has been used for over 30 years as mulch. Just smelling it makes your mouth water for something chocolate! Cocoa shells slowly decompose and contain about 2.5 percent nitrogen, 1 percent phosphate and 3 percent potash, according to Auburn University Soil Testing Labs. Because it is feather-light, consumers are often advised to water it to keep the shells in place. This means no air circulation as the shells are compressed by the water. Although the shells are clean, they are still an organic product meant to biodegrade into your soil. Excessive rain in spring and summer as well as watering to keep the shells in place can cause a mildew-like mold to appear as the shells naturally decompose. Try to avoid excessive watering and keep air circulating through the shells by lightly top raking. They are meant to disintegrate, amending the soil as they do so. If you are mulching with cocoa shells in breezy areas of your yard, you might consider an alternative mulch that is slightly heavier and not subject to wind dispersal.