How Long Can Roundup Be in the Ground Before You Can Plant?

Roundup is absorbed by plants and doesn't linger in soil.

Roundup is a systemic herbicide with the active ingredient glyphosate. It acts on plants through direct contact and absorption into leaves and stems. Glyphosate doesn't linger in soil to kill weeds -- it's effectively inert. Once the chemical solution dries on the plant or soil, it can't be transferred elsewhere.

Function

Applying Roundup to a garden bed with weeds acts to kill all existing plants. Ample time must pass, roughly 72 hours, for the glyphosate to be absorbed and then transported through plant vascular tissues to all plant parts to kill the plant. Don't chop off weeds too quickly after spraying to prepare the bed for planting.

Time Frame

Once extant weeds absorb the chemical and dry and yellowing or wilting occur, the weeds can be tilled under or raked away. Plant other rooted trees, shrubs, perennials or annual plants after the residue of Roundup is fully dry. Wait 24 hours or more if excess humidity or dew is present.

Warning

Once you sow seed or plants in an area, do not apply Roundup flippantly. Roundup's chemicals will kill any and all plants that absorb it in spray form, including damp, swollen seeds or germinated sprouts.

References

• Natural Pest Control Information: Roundup
• Free Plants: Tips for Preparing a Planting Bed