Agronomy •  2023-02-24

Assessing Swath Timing via Seed Colour Change

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How do you know when to swath? Believe it or not, your seed will tell you. One of the best and most reliable ways to ensure you’re getting the most from your crop is to look at seed colour change.

Agriculture experts agree that 50-60% seed colour change (dark to black seeds) on the main stem is the ideal time to swath. This means getting right into the field for some hands-on CSI (crop science investigation).

Five steps to assessing swath timing via seed colour change

1. Pull a plant

Look for plants that best represent the entire field. Avoid underdeveloped or larger plants. Identify the main stem.

2. Begin opening pods from the main stem to examine seed colour.

Start at the bottom of the main stem. Lower pods should be more mature (darker seeds) than upper pods. Pods that have begun to fade from a dark green to a lighter yellow are a good sign of ripening. These pods will have darker seeds. However, scalding from the sun can make pods look more mature than they really are, so it is important to open every pod to examine the seeds within.

3. Move up the main stem.

While it is not necessary to check every pod, growers should check at least 4 samples (lower, lower-mid, upper-mid, top). The development of darker spots on seeds indicates that it is well on its way to ripening.

4. Check the top pods.

In many instances the upper pods will be much greener. Roll these seeds between your thumb and forefinger. Firm seeds that withstand pressure indicate ripening.

5. Look at a side branch

Repeat the examination process with pods on the side branch. Firmer seeds on side branches indicated that the crop should be ready to harvest in approximately 3-5 days.

The advantage of morning & evening swathing

Once you’ve made your decision to go into the field, try to swath early morning or later into the evening, when temperatures are no higher than 22°C or 23°C, to prevent green lock and red seed.

Have questions on this or other canola related topics? Contact your local Pioneer Sales Representative.