If you mean broad leaf weeds such as lambsquarter, ragweed, dandelion etc. then Butyrac 200 is about the cheapest/effective herbicide used on clover, legumes etc.
BUTYRAC 200 BROADLEAF HERBICIDE IN ALFALFA & CLOVER

I usually mow/clip my red clover twice. Once around mid-may and again around the first of july. It mainly will depend on rainfall/season also. I will wait till 25 to 50% of the clover has bloomed on the first cut and just over 50 % on the second cut.

Its very possible you will not need a chemical application, especially with the red clover, it usually out grows and smothers competition. Grass is more of an issue because it rebounds quickly after being cut and feeds off the nitrogen being produced by the clover. For grass control, depending on the type of grass, I have better results using Arrow or any brand that contains Clethodim.

If you're located near a Southern States coop, I would check there for prices on herbicides, the one located here has the chemicals mentioned and are reasonably priced. Most will gladly offer advice also.

ARROW GRASS HERBICIDE


POAST PLUS GRASS HERBICIDE