Hi Greg... Using Roundup months before planting anything is not a problem. It works when the plant soaks up the Roundup, and kills that plant all the way to the root. Which is why many of us keep a whole lot around...because it kills the plant you put it on (weeds in our case) but others can grow back in its place (or close to it...)...So I generally make several rounds with the stuff in the summer..about six weeks apart.... It would probably kill tomatoe plants as well if it were sprayed on them...but as it is in your case, it should be fine..... Just don't spray it around your yard on a windy day! Take care, Jan Taylor San Antonio, Texas Greg Park wrote: > Hi all, > > A nice friend of mine has decided to let a poor soul like me use part of his > backyard for growing some tomatoes!! However, he sprayed a weed killer > called "Round up" over the area a few months back to kill off some tall > weeds (he was planning to cement the area but ran out of money) > > Is anyone familiar with Round-up and it's effect on gardening? I've been > told it is a 'systemic' weed killer, although I'm not quite sure what that > means exactly...Should I till the soil or will that put the poison in the > soil deeper and be a long term detriment to my tomatoes? Is there anything > I can add to the soil to counter act any lingering effects? > > Trying to avoid a disaster... > > Greg Park > zone 10 > CEO-in-Training > Park Steel Company, Inc. > Park.Steel@worldnet.att.net