Sometimes it may be better to spray with Roundup or its generic equivalents. It all depends on the type of weeds and their root system. Using a chisel plow helps to spread the root system of some weeds. If roundup is used, sometimes it is best to not till the soil. Working the soil can bring up new seeds which will then germinate. Roundup onlykills the plants thatare up and active. If Roundup or a similar chemical is used, I suggest waiting ten days to two weeks before you work the soil. Yearly use of a particular chemical weed killer is not a good practice. You increase the chances of having mostly weeds that are immune to that chemical.