How can I keep cats out of my flower beds? They keep using them as a litter box. I’ve heard to use cocoa hull mulch or eggshells since cats don’t like to step on them. Is that safe, and will it work?
One of the main results I found is that cats are unpredictable, so you might want to try a
few possibilities. The most reliable approaches seem to revolve around creating
smells, textures, or situations that cats dislike.
We don’t recommend using cocoa beans or eggshells to prevent cats from going into your flowers.
Cocoa bean mulch is toxic to dogs and possibly other pets. In fact, it has more concentrated theobromine per ounce than most chocolate products. This page from the ASPCA (now archived) has more information, and it is further confirmed at Snopes.com, a site that evaluates word-of-mouth knowledge and urban legends.
Eggshells, on the other hand, are nontoxic, but seem likely to attract pests and thus create a new and different
animal problem.
Instead, there are a number of other solutions you might try. One that a
librarian here has had success with is planting strong-smelling plant like
lavender (Lavandula spp.) or other herbs (but NOT catmint, also known as Nepeta!).
Another tactic that might not offend your nose is to make the area unpleasant to
use as a litter box. In particular, you can make it unpleasant for cats to walk through and dig in. Laying chicken wire or hardware cloth out over the garden bed is said to be successful sometimes, though it would be difficult to do after plants were established. Another possibility would be making a ground-level lattice of thorny branches, like rose prunings, around established plants. Other possibilities include a stone mulch or some other kind of bristly mulch, such as prickly pinecones. This article discusses these and other cat repellents.
Please note, though, that we don’t recommend all of the ideas you will find there, like scattering mothballs in your garden, which is just as likely to be toxic to you as to the cats. You don’t want to harm yourself or anything else!
If you are looking for a long term solution with no toxicity and some fringe
benefits like doing your watering for you, motion activated sprinklers are
highly recommended as a cat repellent.