Monitoring Cotton Growth

After stand establishment, it is necessary to monitor the growth rate of cotton to determine whether or not a cotton field is making acceptable progress. Although growth and development will vary from area to area, the rate of development is related to degree days and should be fairly constant. When growers and consultants monitor and record DD60s, they make more accurate estimations of growth and development deviations from acceptable growth in their fields.

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DD60s are a measure of the energy available for growth. This equation is accurate whenever the minimum temperature is greater than the lower threshold (60 ̊F).

Growth Stages Indicated By Accumulation of DD60s and Days

Average Low High DD60s
From planting to emergence 7 4 10 50-60
From emergence to first fruiting brand 24 21 27 300-340
From emergence to first square 32 27 38 425-475
From emergence to first white bloom 55 50 60 825-875
From emergence to peak bloom 90 85 95 1385-1435
From emergence to open boil 110 105 115 1700-1750
From emergence to 60% open boils 140 135 145 2180-2230

Certain events in the growth of cotton occur at a set number of DD60s after planting. Although there is some minor variability between varieties, most varieties are similar enough that a table of growth stages as related to DD60s can be developed. Remember that varieties will vary slightly, and environmental conditions (such as water stress and fertility levels will also impact growth.

This article is from the Cotton Management Guide, a publication with year-round advice on managing high-yielding cotton. Download the Deltapine Cotton Management Guide now or sign up for new content to be delivered to your email each month.​​​

Click here to learn about cotton growth physiology.