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One cotton expert’s take on the 2021 season and how to mitigate risk with a late-maturing crop.

Ginger Rowsey, Senior writer

August 12, 2021

4 Min Read
Cotton Blooming
For much of the Midsouth, the latest date growers can count on a white flower contributing to yield is quickly approaching or already passed. Following research-based termination timings are the best bet for saving yields and profitability. Ginger Rowsey

When you ask Bill Robertson how concerned he is about the lateness of the 2021 cotton crop, his answer is simple. 


Robertson, the Extension cotton specialist with the University of Arkansas System Division of Agriculture, says he has rarely seen a cotton crop as late as 2021. While most cotton was planted later than average, the crop went in at about the same rate as 2020. However, as we’ve witnessed, 2021 weather has done everything it can to make a late crop later. 

“We had winter and spring, then another winter and spring,” Robertson said. “Every cotton grower I talk to say they are running two to three weeks behind where they normally are.”  

“Typically, growers will have a few fields that are later maturing, but for many growers this year all of their fields are going to be late. That will make timely harvest difficult and could cause yield reduction. There is a lot of potential out there, but I’m worried we don’t have enough calendar left to see it through.” 

Growers have spent heavily on this cotton crop that may or may not produce the record-breaking yields of the past two seasons. While most of the crop management is through, Robertson says a focus on protecting fruit while recouping costs and maintaining profitability will be crucial. 

“Our goal is to get as much black ink on the ledgers as we can,” Robertson said. 

Stop spending money? 

The immediate challenge for cotton growers is figuring out when they can safely stop spending money without sacrificing yield. Robertson says determining cutoff date is the starting point. 

“In most years we can used a plant-based cutoff date. In Arkansas, we recommend the day the crop reaches nodes above white flower five (NAWF = 5), but in a year like this I think it’s best to go by calendar date which uses historical weather to determine the last date that a flower has a reasonable chance to make a harvestable boll.” 

For Arkansas those dates range from Aug. 10 in the northern end of the state to Aug. 23 in the southern end. 

“Growers may be tempted to push their cutoff dates later, but I think that’s very risky,” Robertson adds. “We just can’t predict what the fall weather will do.” 

Once a cutout date is determined, growers can track heat units to determine accurate input termination timings. 

“You can stop plant bug applications after 250 heat units as long as fields are below threshold. For bollworm it’s 350 units and clean fields. 450 for stink bugs. We wait until we’ve reached 600 heat units for defoliators. We have to have leaves on the plant to have the energy to feed the bolls. For harvest aid applications, we typically say 850 heat units.” 

The University of Arkansas recently unveiled a new online DD60 Cotton Growing Degrees Day Calculator.  


“For irrigation termination, the rule of thumb is to irrigate until first open boll. Very seldom have I watered after 600 heat units after cutout. When we get 10 days past cutout, we can start stretching water out. We don’t want to turn water off too soon, because we want to want to keep feeding the bolls, but after 10 days past cutout we can start tapering off on irrigation. This will put good stress on the plant and help it start to senesce.” 

“A general rule is that September watering in cotton does not pay,” Robertson adds, “but again, we just don’t know how weather in the coming weeks could affect us.” 

Pray for warm September 

Even with best management practices, Robertson acknowledges that much of the fate of the 2021 cotton season now depends largely on the weather. 

“We’re going to have to have some help from Mother Nature. If you look at long-term data, the best cotton yields typically occur when we have a cooler than average August and then good heat units in September. The last thing we need is a cold September.” 

“At this point, determining cutout dates and following termination guidelines will help producers better manage inputs and their costs without having a negative impact on yield and quality. Managing costs will be even more critical in a year that yields may be closer to average as compared to record breaking that we have experienced the last few years.” 

“Nov. 1 is our target harvest completion date. Getting harvest aid applications initiated in a timely fashion is key to getting the pickers in the field and harvest completed to help preserve yield and fiber quality potential. Nothing about harvest works good in the mud and the last thing any of us want is to still be harvesting cotton in December.” 

About the Author(s)

Ginger Rowsey

Senior writer

Ginger Rowsey joined Farm Press in 2020, bringing more than a decade of experience in agricultural communications. Her previous experiences include working in marketing and communications with the University of Tennessee Institute of Agriculture. She also worked as a local television news anchor with the ABC affiliate in Jackson, Tennessee.

Rowsey grew up on a small beef cattle farm in Lebanon, Tennessee. She holds a degree in Communications from Middle Tennessee State University and an MBA from the University of Tennessee at Martin. She now resides in West Tennessee with her husband and two daughters.

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