I am covering my garden with plastic this year to help with weed control......i have 4 mil plastic and im wondering if that is to thick?.....Thanks for your help

If you're using the inexpensive 4ml plastic from somewhere like Home Depot, it will disintegrate in the sun in less than 2 months. The summer we tried using it, what a mess it made with small pieces everywhere. You can put it down for a few days in the sun to kill the tops of weeds, but don't leave it out long term.

I don't understand why you think the plastic could be too thick? For solarizing our beds through the summer here in FL we use 6ml greenhouse grade plastic sheeting. It's available online if you just google "greenhouse plastic".

Would you please fill in your profile with your location - city, state, country? It will help us to answer questions you have in future.

@kajett
I have used 4 mil black plastic in my vegetable garden to retain moisture, eliminate weeds, warm the soil - for my tomato, pepper & melon crops.
But that field is plowed down each fall and all traces of the plastic are removed, washed/sanitized, dried and re-rolled for winter storage. The plastic can last for up to 3 years.
For the permanent plantings in my perennial beds I used commercial poly fabric woven fabric mat used as a foundation for road construction. When I initially designed my perennial beds, I layered manure, element nutrients that my soil test revealed I needed, roto-tilled the works, laid the fabric mat, tucked the edges, pinned the seams, scored the planting spots, dug the hole, planted the perennial, broadcast 3" shreaded hardwood mulch.
That fabric mat has lasted 25 years. Of course the wood mulch has to be replenished every 4 years. If a plant dies, it is removed and the scored flaps are smoothed back in place and wood mulch applied.
When a perennial, like this hosta, outgrows its scored hole, I simply score the fabric back further and tuck it under.




I'm due for a couple of loads of wood mulch, but this gives you an idea of the end result.