Question: how long do you have to wait before planting after using roundup?
Answer: How long do I have to wait to plant after spraying weeds with Roundup? -Ron. According to Scotts, the manufacturer of Roundup (glyphosate) weed killer, its safe to plant ornamental flowers, shrubs, and trees the next day; and they say you can plant grasses and edible plants and trees after three days.