Counting the Degrees to Find the Best Time for Planting Cotton in the Central Valley

Drive around the Valley and you’ll see future cotton fields in waiting

“All the fields are ready. The rows are ready,” says field scout Carlos Silva. “I’ve even seen some pre-irrigation.”

Some cotton growers have started to pre-irrigate their fields.

Certainly, the recent string of sunny, warm spring-like days (How did everyone like the near-90 degree weather last week?) certainly put growers in the mood for planting the seeds for another cotton season. 

On paper, March 10 was the first official day that San Joaquin Valley growers could plant cotton. That date marks the end of the 90-day host-free period for the pink bollworm control program. Of course, that date usually isn’t a realistic start time. 

Carlos believes the first planting could come at the end of March or early April. Right now, growers are checking the weather forecasts, measuring the temperatures and working on calculations. 

Growers have prepared fields for this year's cotton season.

Of course, Mother Nature will have a big say. While today marks the first day of spring, the weather forecast this week is more winter like. Predictions call for a few days of rain and cooler 60-degree temperatures this week.

“If growers see any rain in the forecast, they are likely to hold off planting,” Carlos says.

When is the best time to plant?

Here’s what UC IPM says: “To determine the best planting date to establish a healthy stand, use a 5-day forecast of accumulated degree-days (heat units) and on-site soil temperature readings. Good stand establishment requires sufficiently warm air (measured in heat units) and suitable field soil temperatures.” Growers can use UC IPM’s Cotton Planting Forecast online site plus soil temperatures until an optimal planting date is determined.

“Cotton seed requires approximately 50 degree-days to accumulate in order to emerge when planted at an optimum planting depth. It is also important that temperatures be consistently warm and don't drop during the first 5 days after planting,” UC IPM adds.

 

FIELD DAY: Almond growers will learn about honey bee health and receive valuable disease, fungicide and pest management tips at a March 28 field day. The free event will be from 10 a.m. to noon at the Cook Orchard, 15640 Avenue 22 1/2, Chowchilla.  David Doll, a Merced County UCCE pomologist, will review bloomtime diseases found in almonds, chemical treatments, including the proper selection of fungicides and nitrogen applications. Florent Trouillas, UCCE fruit and nut specialist at the UC Kearny Ag Center, will explain the complexities of many wood cankers found in almond trees. He also will offer tips about treating the problem, including chemical and mechanical management practices. Sponsored by San Joaquin Sustainable Farming Project, the field day offers one hour of continuing education credit. For more information contact Project Director Marcia Gibbs at (530) 370-5325 or at marcia@sustainablecotton.org.