Rainfast is the time it generally takes for a herbicide application to not be impacted by rain. Always check the labels as updates do occur.
Some of the newer ones aren't listed, will update later.
http://www.docstoc.com/docs/document...doc_id=4868447
http://www.afschem.com/Pictures/Rain...0Herbicide.pdf
Herbicide Rainfast Chart
Linear Mode
