Timing Glyphosate Application When Planting Spring Bulbs: Spray First, Then Plant

A gardener in Pennsylvania planned to spray Roundup (glyphosate) on weeds, then plant spring bulbs a few days later. He asked whether to spray before or after planting, and how long to wait for the herbicide to translocate to roots.

Spray First, Then Plant

Apply glyphosate to actively growing weeds. Disturbing weeds during planting can cut roots that haven't yet received the chemical, allowing regrowth.

Translocation Time

• Hot, sunny, windy: 1 day.
• Cool, cloudy, 40°F soil: 1 week or more.

In typical fall conditions, wait at least 3 good sunny days before planting.

Follow-Up Control

Glyphosate isn't absorbed by bulb roots. After bulbs emerge, you can spot-treat any surviving weeds by painting glyphosate on their leaves with a sponge or brush—just avoid bulb foliage.