Someone explain to me when to sheet mulch!!

[Anonymous]

Do you sheet mulch in the winter for beds in the spring? Won’t weeds reestablish themselves by then?
Or should I sheet mulch in the spring? If I put seeds on top (cosmos) will roots be able to get through the cardboard?

[Anonymous]

What are you trying to achieve? “Sheet mulching” can mean different things to different people. Some people are talking about multiple layers to build a raised vegetable bed. Some people just mean using cardboard to smother grass or weeds.

If the latter, you can do it now. If you cover the ground with cardboard, then a layer of compost and/or mulch, the cardboard will be mostly gone by Spring and your cosmos seeds will be fine. You probably will kill the grass but probably not tough perennial weeds like dandelions and I bet some annual seeds would also survive, because they’re dormant now.

If you do it in Spring and leave it over the summer it will do better at smothering weeds, though some might still survive and new weeds will blow in and grow on top of the mulch.