Easiest way seems to be placing down chicken wire over the squares at planting time. If a cat can't "fluff" the soil, it won't go there. Safe for the cat as well.

i seen on another site here that people put down forks and knives (plastic) the handle end down, all over in the garden area, and the cats and dogs will stop going in there. they start to get into there and get poked and usually thats the end of that. i'd use the clear ones!! secret weapon!! evil meaness!!!! LOL ~Medo

Chicken wire would be fine for some plants whos parts are harvested above ground, but how would you treat a bed of root crops? Can't pull a beet or an onion or a carrot, etc., through chicken wire.

Granny

Here is a link that might be useful: Annie's Kitchen Garden

I think you'd remove the chicken wire before it was too late to do so. I agree leaving it in place would be problematic for root crops.