Cat Poop in My Box Planter!

It seems that some of the neighborhood cats have been using my above-ground box planter for a litter box. Sadly, I had been planning to use that planter for growing edible herbs this year, but now I fear that bad bacteria and viruses may be present in the planter from the feline excrement. Any suggestions about a good way to sterilize the bad guys out of my planter soil? I'd really rather not have to empty the entire planter and refill it with clean dirt, and I really don't want to take the soil out and heat it to 130°F, although I suppose those are last-ditch options. Or maybe I can just wait until next year and the bad bugs will all be dead. Thanks for any thoughts and recommendations.

In colder climates with a good winter you can just clean out any visible deposits and plant. In your location I'd suggest removing any visible deposits, skim off the top 3-4 inches and dispose of it. Replace it later with some fresh mix. Then fully saturate the remaining soil with boiling water and let it bake well in the sun.

There has been a great deal of research done on this issue and the consensus is that any threat is minimal given weather exposure and time, and the lack of live tissue to support bacterial growth.

But how comfortable each gardener is with using the soil is an individual choice. So you have to determine what you will be comfortable with. When making your decision do keep in mind that (1) the plants don't just 'suck up' any contaminants in the soil. If that was the case we couldn't garden in any form of dirt. And (2) you will be washing your produce before eating it anyway.

Dave

Going forward you might want to do something to prevent the animals from doing their business where you don't want. If you don't care much for your neighbors, use a live animal trap baited with some food and take the felines to the SPCA or similar organization. If you'd rather not do that, I would suggest taking 1" chicken wire and anchoring it at the soil level. This will prevent animals from digging around in there and I would think it would keep a cat out as it would not be able to dig. Just a theory, I haven't tried it but I do know it keeps squirrels from digging up fresh planted bulbs.

I agree with Dave. And in keeping with preventing new digging, maybe a layer of stone will do that. Many herbs like that anyway. Should keep the cats out and the 'dirt' down under the surface

I have found two mulches that work well to discourage cats- crushed hazelnut shells which are a bit hard and sharp (but roll around on the driveway but this would not be a problem in planters), and cocoa shells. The cocoa shells are expensive, and seem too lightweight to stay in place, but when they get wet they get a slightly gel-like exudation that sticks them together, then they never blow away. For some reason the cats don't like them. I love the smell.
Putting rocks or gravel in a box where you want to put food crops in every year could be a problem. The shells eventually break down and add to the soil. The hazelnut shells take years to really break down. Hazelnuts are grown commercially in the Pacific Northwest, so they are not too expensive. In Texas maybe pecan shells would be available.

Coarse chunky bark mulch may suffice too.
My cats seem to like dry leaves, so don't get anything fluffy.

Cats have a very strong sense of smell. If you spritz the soil with something like Liquid Fence, even one time (it's very safe for veggies), it's possible they'll never use that area again. To be on the safe side, you might want to spray it a few times when the veggie plants start to grow. There's even a Liquid Fence specifically for cats & dogs.

Cats can be so fussy about the scent of where they do their stuff, that people sometimes complain about their kitties refusing to use litter boxes with some of those fancy new types of litters.