Come the beginning of September, most grower should have one thing on their mind. No this should not be dove hunting, but rather planting. When it comes to canola producers, it is this time of the year that many want to start getting seed into the ground if moisture is present. With recent rainfall throughout a good portion of the state, this decision is starting to being made this week.
Should this be done:
Determining whether you should plant early or not depends on your situation. First and foremost, for insurance purposes, insurable planting begins on or after September 10th and goes through October 10th. This would basically call for waiting until at least this Saturday to start planting. However, with moisture, many producers would be more apt to plant into good conditions than to wait for the optimum timing and plant. This is understandable; however, there are other things that need to be considered.
When planting early, many producers just want to ensure that enough growth has been achieved before the first killing freeze to store enough reserves in the plant and rooting system to survive the winter. This is a good thought to always have when planting canola but canola only needs around 6 weeks of growth to increase the likelihood of winter survival. Planting on September 6th would result in 8 weeks before the average light frost (November 2nd, NOAA), 10 weeks before the first hard freeze (28F, November 14th, NOAA), and 12 weeks before the first killing freeze (24F, November 25th, NOAA). If a large amount of growth was the only factor in achieving high winter survival and good stands in the spring, then planting into good conditions as early as possible would be the best practice. However, with increased vegetative material, a high amount of water and nutrients will be needed to sustain the plant in later winter and early spring. This increased stress can result in diminished winter survival and spring stands.
Managing early planted canola:
Recent research projects at Oklahoma State University have begun to look into the use of PGR to manage fall canola growth. Results of these trials have been somewhat mixed. While a PGR that restricts growth when the canola is planted early or a PGR which increases root growth when applied to late-planted canola did not decrease yields, no yield benefit were found either. These results currently show that the addition of these PGR to most winter canola producers are not cost effective as a means to manage planting dates with our canola crop. Additionally, while not significantly, higher yields were typically seen when the canola was planted on-time rather than outside of the optimum window and then managed with PGR. Furthermore, most PGRs are not labeled for use in winter canola production. Those that are labeled for use are labeled under a different use (i.e. fungicide) and therefore application as a PGR would be considered an off-label application.
Overall, winter canola planting can be a challenging time full of decisions that will influence the productivity of the remainder of the production season, especially in Oklahoma when September through October can have highly variable weather. An optimum planting time for canola will typically occur around the 20th of September. No-till growers need to start making this decision earlier as these soils have a tendency to restrict growth and become cooler faster than conventionally tilled soils. Even if producers wait until the last two weeks in September to start planting canola and moisture is not present at that time, the planting window stretches for several weeks beyond that time.
We at Oklahoma State University wish all producers a safe and productive planting time. If any further guidance is needed regarding planting issues feel free to contact your local county extension office, regional agronomist, or myself with any other issues.