Last year, wheat winter progressed quicker than usual due to warm temperatures. In our Pickaway County trials in 2016, wheat reached Feekes growth stage 6.0 by April 6. This year, with unusually warm temperatures, we may see something similar. Don’t rely on calendar date. Check your fields for growth stage.
Freezes can be a concern when wheat progresses earlier in the spring. Last year, we evaluated winter wheat freeze damage at several growth stages. At Feekes growth stage 5.0, very little to no injury was observed at temperatures as low as 14°F. At Feekes 6.0 (jointing), wheat plants were sensitive to temperatures of 24°F and lower. We are continuing our wheat freeze work this spring.
Feekes 5.0: Leaf sheaths are strongly erect. Plants will have an upright appearance, but the growing point is still below the soil surface.
Feekes 6.0: Prior to Feekes 6.0, the nodes are all formed but sandwiched together so that they are not readily distinguishable. At 6.0, the first node is swollen and appears above the soil surface. This stage is commonly referred to as “jointing.” Above this node is the head or spike, which is being pushed upwards eventually from the boot. The spike at this stage is fully differentiated, containing future spikelets and florets.
By Feekes 6.0, essentially all weed-control applications have been made. Do not apply phenoxy herbicides such as 2,4-D, Banvel, or MCPA after Feekes 6.0, as these materials can be translocated into the developing head, causing sterility or distortion. Sufonyl-urea herbicides are safe at this growth stage, but for practical reasons, weed control should have been completed by now. Small grains can still show good response to N topdressed at this time.
To identify Feekes 6.0 growth stage:
1- Pull, or better yet, dig up, several clusters of tillers with roots and soil from multiple locations in the field;
2- Identify and select three to four primary tillers from each cluster – usually the largest tillers with the thickest stem, but size can be deceiving;
3- Strip away and remove all the lower leaves (usually small and yellowish or dead leaves), exposing the base of the stem;
4- Now look for the first node anywhere between 1 and 2 inches above the base of the stem. This node is usually seen as a slightly swollen area of a slightly different (darker) shade of green than the rest of the stem. If the first node (and only that node) is seen at the base of the stem, then your wheat is at Feekes growth stage 6.
Here is a video showing how to identify Feekes 6.0 growth stage: https://www.youtube.com/watch?v=iukwznx4DPk