ProCrop

Frost Effects on Canola Swathing Time

The recent frosts have raised many questions regarding the time of swathing as it relates to frost damage. In normal years, the optimum stage to swath for both yield and quality is up to 60% seed color change. However, the early frosts and abnormally cool weather may have altered the decision making process. The condition of the frost affected areas fall into three main categories, with appropriate swathing strategies for each category. Carefully assess each field and note which scenario the majority of the plants fall into.

Scenario 1: when there is little evidence of frost damage. The pods remain mostly green or tan-green, with few, if any, white spots on the outside of the pods. The seeds inside are mostly intact. Check the color of the inside of the seeds as well. If the outside of the seeds are starting to turn, the insides should be yellow or a light lime-green. If seeds are still green on the outside and the inside of the seeds are still watery, the outside seed coats should remain intact and turgid. In these cases, leave the crop to continue to mature until further seed and or pod color change occurs.

Scenario 2: when there is considerable whitening of the outside of the pods for a majority of the plants. Check the following link for a photo of severe crop damage:

In this case, the pods will begin to shrink and desiccate rapidly, and swathing should begin immediately to reduce pod shelling and pod drop and conserve any seeds in those pods.

Scenario 3: when there are only white specks on the outside of the pods, or only a few seeds in immature pods are not intact, or only a few seeds in the upper plant parts are prematurely browning. Check the following link for a photo of moderate crop damage:

Premature browning occurs when the outside of the seeds have been damaged by the frost and the insides of the seed remains dark green. In these cases, the fields should be left and monitored on a daily basis to evaluate further crop changes. If no further damage is evident, the remaining crop may continue to fill and mature. If the seeds continue to deteriorate and/or pod integrity declines, begin swathing to conserve seed volume.

In all cases, monitoring should be done on a daily or bi-daily basis to evaluate further crop development and conditions, especially if warmer temperatures and sunshine return.

Back to Fall Frost - Environmental Damage Menu
Back to Environmental Damage Menu
Back to Main ProCrop Index

Further Contact Information