After a long dormant winter it is important to assess your winter wheat crop in the spring when the snow has melted, the weather has become warmer, and your crop will begin to grow again. There are many things to look at when assessing your winter wheat in the spring. Here are the things you should look for:
Winter Hardiness Factors
What was the plant stage before freezing?
It is important that your plant has a developed crown (three leaf and a tiller) before going into winter. A plant at this stage has maximum reserves and will be able to resume growth in the spring. Optimal seeding date and depth are important in seeing this stage before winter.
What was the snow cover over the winter?
It is important that your winter wheat crop be covered in four inches of snow (light and fluffy snow is best) for the coldest part of the winter (December 22 to March 20) to buffer from extremely low air temperatures.
This is an important nutrient in creating winter hardiness for winter wheat. It also helps in spring recovery of damaged plants.
Assessing Winter Wheat Survival
By removing a few of your winter wheat plants on a warm day, you can easily assess your winter survival. Keep the crowns on a moist paper towel exposed to light in a warm room for a few hours, maybe a day. If the crown tissue is damaged it will turn brown. If the tissue is not damaged it will stay white and begin to produce roots in a few days. Assessment should be made of the “worst-case” areas, where fertility may have been poor, snow cover was lost in cold temperatures, and/or plants did not develop the crown before winter. If the plants have survived in the worst-case areas the rest of the plants in the crop that did obtain these things should be fine.
Winter survival cannot be determined by leaf colour in the field. A brown leaf may not mean the plant is dead and a green leaf may not mean the plant is alive. Winter wheat plants need time to recover, so it is important to scout the crop as late as possible. When the plant has grown new roots, then new leaves will form; this will be aided by cool damp weather. If there is hot dry weather in the spring it can cause cracking and drying of the soil, which will be detrimental to the plants. Winter wheat crops should be assessed between May 15 and 25.
Don’t be alarmed by a thin stand in your winter wheat. Due to its excellent ability to tiller, winter wheat can be thin but still produce an excellent crop. Because winterkill often occurs in patches it can be difficult to assess plant population, so this shouldn’t be a reason to reseed. The optimum plant stand is 20-30 plants per square foot; however, 10-15 plants per square foot can still produce a profitable crop.
If You Choose to Reseed…
Some agronomic factors must be considered if reseeding after a winterkilled winter wheat crop. Reseeding to another wheat could cause an infestation of the Wheat Streak Mosaic Virus, so that should be avoided. Also, broadleaf crops (pulse, flax, canola) should not be seeded on land that was treated with 2,4-D in the fall or early spring. Remember to credit fall fertilizer.