July and August are ideal months to get a head start on weed control. Last Quarter phase is a good phase for weeding because seed germination tends to be lower then, and you are less likely to stimulate further weed seed germination while removing weeds. Many weeds that germinate in cultivated soil are and pests that damage vegetable crops. July is too late to eliminate the lawn weed Bindii as the spiky seed heads will be starting to form.
You can find organic treatments for troublesome weeds in the ‘Weeding Between the Lines’ category on this blog.