Which is the best herbicide to remove the weed from the lawn? And when is the best time to do it? Thanks!

This doesn't really address the chemical issue, but I am finally winning the crabgrass battle by seeding red clover every other February. Clover isn't as aggressive as the crabgrass around here, but where it takes it's so dense that the crabgrass doesn't spread.

I don't like herbicides except for plain old vinegar.
I once walked on some treated grass in my bare feet and both feet swelled up horribly. Who needs chemicals on our skin, pets, and in our ground water?

I don't like herbicides except for plain old vinegar.
I once walked on some treated grass in my bare feet and both feet swelled up horribly. Who needs chemicals on our skin, pets, and in our ground water?

5% Acetic Acid (plain old vinegar) is a chemical produced by the fermentation of ethanol (booze). Ground water is contaminated Dihydrogen monoxide (H2O).

The more you know ...

I think I'll try the clover too!