Early season weed control is important for preventing yield loss, as peas are poor competitors against weeds. A pre-seed or pre-emergent herbicide application is recommended, along with a timely in-crop application, applied when weeds are small and actively growing.
But Beware!! Field peas can grow very rapidly after emergence if growing conditions are favorable. In ideal growing conditions, a field pea can add a new node every five days. In warm soil conditions, that growth rate can accelerate to two node stages every seven days! That is two node stages a week. The window for post-emergent herbicide application may be very narrow this year if the current weather forecast rings true.
It is essential that growers and agronomists properly stage field pea crops and, whatever you do, do not use crop height as viewed from the pickup as your measure. Looks can very deceiving.
- Post-Emergent Herbicide Options for Pulse Crops 2026 courtesy of the Saskatchewan Pulse Growers →
- Table 7. Weed Control in Field Pea – Guide to Field Crop Protection courtesy of Manitoba Agriculture→
Along with the Field Pea Growth Staging Guide, here are some tips to keep in mind when staging peas:
- Peas always have two scale leaf nodes at the base of the plant. These may be above or below ground or a combination of both. Scale leaves are smaller than true node leaves and branches may develop from these scale nodes.
- To properly determine field pea growth stage, dig up plants to identify scale nodes as they are not counted when staging.
- The first true node leaf is the first stipule (leaf) and tendril that unfurls. Only true nodes are counted when staging for herbicide timing. If unsure, err on the side of caution.
- Subsequent nodes are counted once the clam leaves have unfurled. Unopened clam leaves are not counted when staging.
- Base staging off of the majority of plants in the field.
Make herbicide applications early, when weeds are small and actively growing for best control. Avoid applying herbicides if the crop is under stress from recent frost, excessive heat or drought. Wait three days for the crop to recover.
Make herbicide applications early, when weeds are small and actively growing for best control. Avoid applying herbicides if the crop is under stress from recent frost, excessive heat or drought. Wait three days for the crop to recover.