I just moved into a new house, and the people who lived here previously did not ever weed their garden. Literally every square inch is covered in weeds. I am now trying to take care of this garden, and after I am done weeding, how do i get rid of the remainder of the roots that are still in the dirt? I really don't want to weed and then have the entire garden in the same condition in a week (with weeds sprouting in every nook and cranny)