Much of Oklahoma’s dryland cotton has begun to stress, says Extension cotton specialist J.C. Banks, prompting mostly dryland growers to question the crop’s potential to make a decent yield.

"Where cotton has moisture it has responded with rapid growth and fruiting." Banks says. "Irrigation is on full schedule for those with water; cotton is using some of the subsoil moisture received in early spring in dryland areas."

Don’t give up yet, Banks, advises.

"Cotton growth and development is controlled by heat units received, but we can get reasonably close by counting the number of days," Banks says in a weekly update for NTOK Cotton (an industry partnership that encourages production on the rolling plains of North Texas, Oklahoma and Kansas).

"From pinhead square it takes 21 to 23 days to produce a white bloom. In one to two days, the white bloom will turn red and fall off. This is officially when the fruiting form becomes a boll. Boll development from this stage to full maturity requires 50 to 55 days for the boll to open and be ready to harvest.

"The fiber elongates and develops maximum length during the first 16 to 18 days following bloom drop," Banks says. "Any severe stress during this period can cause short fiber content. The extent of short fiber will depend on the number of bolls in this critical stage when the stress occurred.

"Micronaire develops after fiber length occurs. Low micronaire problems occur when fiber development is stopped before the boll fully matures. This usually results from cool weather late in the development process. Now we get back to the question of ‘does this crop have time to mature?’

Sept. 1 bloom

"In most areas of Oklahoma we have our first freeze near the first week of November. We normally receive very few heat units during the last week of October, so fiber development will be terminated at this time. Since fiber needs to be mature the last of October, and development from bloom requires 50 to 55 days, a Sept. 1 bloom should have time to mature under normal conditions.

"Since a pinhead square requires 21 to 23 days to become a bloom, a square formed the first week of August should have a good chance of developing into a harvestable boll. Cotton blooming the first week of August will normally have at least six to eight squares above the bloom.

"Weather conditions in August will determine how many of these bolls the cotton plant will keep, but at least this gives us an idea of the potential of our crop," Banks says.