it will tell you on the container the do's & dont's of post applied chemicals Guest. Good luck trying to eradicate horsetail, this is a long term sustained attack to get the better of it.

You will need to wait until next spring to do any planting, I'd be cautious of growing veg there until you know the horsetail is actually gone.

I find that the only thing that gets rid of it is................ a lawn.

Glyphosate becomes inert on contact with soil, so it's sually safe to plant immediately. The horsetail may come back, as MG says, but if you strim it lightly first, to bruise and break the foliage, that allows the weedkiller in to the soft tissues and the core of the plant. Phil J

Phil there is now a body of evidence that glyphosate does not break down on contact with the soil. Hence I would not plant until spring 2011. In fact even before I knew this would not have used on land to grow veg on.

Compost tea, or other forms of "humates" help the soil bacteria to break down glyphosphate residue more quickly. I would apply that now, and again in spring a week or two before planting. Works for many other herbicides and soil contaminants--except toxic metals--too.