Q.Planting After Weeding
I want to end the vicious cycle of weeding by filling in my previously-spacious garden with hostas and ‘step-ables. ‘ I am unsure what to do now that I have pulled all of the weeds (again!) and want to plant the new plants. I was thinking about digging 3-4 inches of the soil throughout the garden, leaving the current plants in place, putting down newspaper, planting the new plants, and putting the soil back but it’s going to have all the weed-remnants and seeds in it. If I treat the soil for weeds, how long do I wait before I plant the new plants? How do I make sure it doesn’t hurt the current plants? How do I prevent weeds from coming back while the new plants grow and fill in the spaces?

Certified GKH Gardening Expert
You are definitely on the right track. Here is my suggestion: Leave the soil, if feasible. Lay wet newspaper six to ten layers thick throughout the area and around your plants. Make sure you overlap the edges by at least six inches to kill any weed seeds that may be present from trying to pop through. Add about six inches of compost or rich soil on top. Put your new plants in this and fill in around your current ones. Top it off with a layer of organic mulch.
If you really feel the need to treat the soil, here is an article that you may find helpful: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-long-does-weed-killer-last-in-the-soil.htm