As a cotton grower, there are times when you have to wear two hats as both farmer and coach. So when local conditions bring high heat and moisture, it’s time to put on your coach hat and implement a playbook to manage cotton growth ahead of harvest.
Scout carefully and apply a cotton plant growth regulator such as mepiquat chloride around the first fruiting branch stage in July. This can help ensure your crop is shorter and more manageable compared to a crop raised without a plant growth regulator (PGR).
Here’s the three-part playbook you’ll need to coach your cotton to a championship harvest season.
Play #1: Measure internode length to determine cotton plant stages of growth
Any winning sports team has a clear goal in mind. For your cotton crop, the goal is to slow internode elongation during active growth, shifting energy from vegetative growth to boll development.
Start by measuring internode length to ensure you don’t miss the PGR application window. The internode is the gap between two nodes, i.e., the space between branches on the plant’s main stem. Nodes should be counted from the top of the plant (newest growth) down toward the soil.¹ If the fourth internode (the length between the plant’s fourth and fifth nodes) is greater than 2” to 3”, a PGR application might be needed.²
Confirm this spacing with a quick test: Hold out one of your hands, stack your fingers on top of each other and see how many of them can fit into the fourth internode. If you can fit more than three fingers into the fourth internode, you might need a PGR.
Miss this window and your PGR is likely to be less effective than it otherwise would be.
Play #2: Time applications of plant growth regulators for optimal cotton plant growth
Try to treat your crop when it’s between 12” and 16” tall.
For dryland cotton, it’s typically best to apply PGR at first bloom at a rate of about 8 ounces per acre.³ It’s possible you’ll need to do a follow-up application or two if your cotton continues to grow aggressively.
For irrigated cotton, it’s common to apply 16 ounces per acre at first bloom, then another round at the same rate roughly two weeks later.
Play #3: Adjust cotton management for environmental or varietal variables
Finally, adapt your approach to using cotton plant growth regulators based on your specific cotton varieties and your growing conditions.
Cotton is at a higher risk of out-of-control growth when it has access to more water, such as in a high-rainfall or irrigated environment. You can also study field history and fertility data to determine whether available conditions might promote high growth–and thus merit the use of plant growth regulators for cotton.
For best PGR results, apply on cotton that is healthy, is well-watered and has access to plenty of nitrogen. PGRs also work best with large, indeterminate cotton varieties.
This approach has an added benefit of mitigating boll rot. That’s because a PGR opens the crop canopy, boosting boll retention and encouraging healthy development.⁴
Experts are available to help you make your cotton plant growth decisions, from kickoff to the final play of the season. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative.
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Endnotes
- Bynum, Jason B., et al. “Development and Growth Monitoring of the Cotton Plant.” Texas A&M AgriLife Extension,https://cottonbugs.tamu.edu/development-and-growth-monitoring-of-the-cotton-plant/. Accessed 23 Apr. 2026.
- Hand, Lavesta, et al. “Cotton Growth Monitoring and PGR Management.” CAES Field Report, University of Georgia College of Agricultural and Environmental Sciences, 19 Oct. 2022,https://fieldreport.caes.uga.edu/publications/C1244/cotton-growth-monitoring-and-pgr-management/. Accessed 23 Apr. 2026.
- Hand. “Cotton Growth Monitoring and PGR Management.”
- “Growing Cotton in Missouri.” University of Missouri Extension,https://extension.missouri.edu/publications/g4258. Accessed 23 Apr. 2026.
