Renee,

The plastic probably can be used in the garden successfully, depending on what kind of plastic it is.

If it is the shiny kind of black plastic that looks like it is just a thicker version of a trash bag, then the issue is that water will run off elsewhere and not be absorbed by the garden soil, except where holes are cut into the mulch for plants. However, this plastic can be used very successfully in garden pathways where you don't care if water absorption occurs. It also can be used in the whole garden if you have cut enough holes for plants that adequate water gets to them OR if you run soaker hoses UNDERNEATH the mulch to ensure adequate moisture.

Another use for this type of plastic mulch is to help warm up the soil more quickly in the spring. You just place the mulch on top of the ground and weigh it down with large rocks or pieces of lumber so it doesn't blow away. Your soil will gain a few degrees of heat after a couple of weeks IF there has been more sunshine than clouds. You then can either remove the plastic, or cut holes and plant through it. If you leave it, though, you'll have to put some sort of mulch (shredded or chipped bark, pine needles, straw, etc.) both to keep weeds from sprouting underneath it and to keep it from OVERheating the ground as the summer heat cranks up.

If it is the nonshiny black plastic mulch sold by retailers like W-M or Sam's....the kind that has millions of tiny perforations to let water through, then the problems begin. Those tiny holes that let water through also let weed seeds, weeds and bermuda grass grow through the mulch, rendering it totally ineffective as mulch. Even if you cover it with an organic mulch like shredded bark, then weed seeds still wash through the plastic mulch's performations and sprout and grow.

If it is the woven plastic that looks almost like fabric and has a finish that somewhat visually resembles felt, it is great as a mulch material as long as you cover it with 1" to 2" of something else, like shredded bark, straw, pine needles, etc. Otherwise, enough light penetrates the mulch that weeds sprout underneath it. I use this kind of mulch and it is great.

Once, my brother put down the shiny black plastic to "suffocate bermuda grass" and planted a couple of plants in it, and then covered it with white rocks. Five years later, he removed the rocks and the plants, which never thrived (I'm guessing they couldn't get enough water) and then lifted up the black plastic.....and those white bermuda runners/stolons were still there and they were HUGE....just waiting for some sunlight. So, we know that bermuda grass can survive under black plastic for 5 years. LOL

Cats are going to be cats. There are some repellets that might work, but they wash away pretty quickly and have to be reapplied often. Sometimes putting something prickly in the bed, like pine cones or the little seedcones that come from sweetgum trees will work to discourage the cats. Sometimes laying down a barrier, like chicken wire will discourage them, but they will return the minute you pick it up. I know someone who stuck plastic forks in the flower bed with the tines sticking up to discourage the cats and it worked, but it wasn't too attractive. What works best for encouraging cats to move on and do their business elsewhere is to put down a mulch of rocks, like smooth river rock or something similar. As I said earlier, cats are going to be cats and you can't really change that.

Dawn