weeds in lawn
How do I get rid of those pesky weeds in my lawn without chemicals? And replant my lawn with grass and clover. Weeds include: lesser celandine (like a carpet), creeping charlie, and hen bit. As of now, I'm using tarp to blocking the sun and rain. Will the lawn be dead by September, when I plan to sow grass seed? Do I want to spread sawdust underneith the tarp (and wood chips on top of the tarp?)
Montgomery County Maryland
Given the time this process will take, we suggest the simpler solution is to remove the weedy turf now and replacing it with fresh sod. The sod will (presumably) be weed-free and a fresh start can be had on weed control going forward. If the sod develops bare patches in the future and you wish to include cover in the lawn mix, you can seed it in at that time. This remove-and-replace option would allow the rest of the garden to benefit from as much rainfall as their roots can access (such as in the covered area, which the tree's roots will permeate). Covering could be shifted to the brick pathway weeds instead, if it would not be a safety hazard, as this area will not have enough plant roots underneath to be of concern.
If you prefer to continue with the smothering of the lawn, the tarp alone should be sufficient. Be aware that Lesser Celandine is tough and stores energy reserves in its roots, and it's possible some of it will survive the initial covering.