Answer: There are some pre-emergent weed products available, whether or not they will help depends on what the weed is. Your county extension might be able to recommend something. However there are some other things you can try that have the added benefit of helping to feed the soil. One is to layer your organic mulch thoroughly and thickly enough to smother those seedlings and prevent them from coming up in the first place. Usually three inches of mulch is enough to do that, but if not, you can layer newspaper under the mulch. A layer about 5 pages thick and overlapped at the edges should exclude light and keep them from sprouting. Also, to prevent blown-in seeds from sprouting, be sure to periodically rake and fluff the mulch in addition to topping it up as needed. I hope this helps.
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