How to Prevent Cats from Soiling the Garden

Cats select soil as the most favored litter substrate. Many deterrents can be tried, but what works for one cat may not work well for another so sometimes it takes a few trials to establish the best strategy.

Because outdoor cats may hunt and thus pick up toxoplasmosis, a parasitic zoonosis it is important to keep yards and gardens clear of cat feces (especially those deposits that are over 24 hours old and thus infectious to humans). This is in order to protect children, or most importantly pregnant women who might be gardening where stool has been deposited. The term zoonosis refers to diseases shared by humans and animals.

An ideal solution is to cover the garden soil with deep layer of mulch including bark chips or strips, gravel or river stones, or other commercial mulch that has components of a large size. Cats love fine sand and soil texture for litter, and do not appear to dig through heavy pebbles or bark chips so these mulches can act as safe deterrents. Unfortunately, the homeowner will incur considerable cost if the garden surface area is large. The layer must be about 4" or 10 cm deep to function properly. Other advantages for the homeowner exist though, and include the proven fact that mulch is effective at reducing weed growth and watering needs, so there are peripheral advantages from the gardeners' perspective.

Fences around gardens have been tried with limited success. A high thin wire mesh fence that is not particularly strong and steady, or a closely spaced picket fence can discourage a cat, but may not be esthetically pleasing or fit into the landscaping theme. Those fences with gaps that can admit a cat will not discourage them.

Booby traps are sometimes set by neighbours, but must be set with care in order not to harm roaming cats. Upside-down mouse traps were often set in the past, but can inadvertently entrap and injure a paw or tail and are not recommended for humane reasons. A safe booby trap consists of a sprinkler system set to water the garden at irregular intervals. This can be a helpful strategy though water restrictions in the local community may make this impractical at certain times of the year.

Another old-fashioned approach was to place mothballs throughout the garden. The smell of them repels the cats, but for environmental and safety reasons, these are not recommended. Young children may think they have found a candy and try to eat one. The active ingredient, naphthaline (NAP) is a polyaromatic hydrocarbon, a known toxin to humans, animals and is classed as a serious environmental pollutant. NAP originates from coal tar and petroleum so if it melts in rainwater, and a cat drinks even small amounts of tainted water, the cat may also experience serious illness because cats are particularly sensitive to the tar and petroleum class compounds. This concern applies also to wildlife such as rabbits and birds.

Another safe, and perhaps the only definitive solution is to let cats out only when their owners are observing them. It is important to make sure cats are not left out on a leash unattended due to a risk of strangulation. Sometimes, they will also slip their collar. A harness is a safer and more comfortable point of attachment for the leash.