Wesley Porter -Extension Precision Ag and Irrigation Specialist, UGA
Most of the cotton should be planted during early- to mid- May. Similar to peanut, cotton does not require very much irrigation during the first month or so of growth and in some cases if adequate rainfall is received cotton can go up to squaring and even bloom without additional irrigation applications. However, if it gets hot and dry again like it did during late March and May of 2019 you may need to apply a small irrigation applications either weekly or potentially a few times per week. The red box below represents cotton water requirements the first five weeks after planting. Keep track of rainfall and temperature, your irrigation efficiency (typically around 65-70% for high pressure systems and 80-90% for low pressure systems), and make irrigation applications accordingly. Keep in mind that the water requirement below is irrigation plus rainfall, and the weekly water requirement recommendation was developed based on a historical average of evapotranspiration. So your actual water/irrigation requirement may vary slightly based on weather conditions and rainfall during the growing season. For a more in-depth irrigation recommendation it is suggested that you look into implementing a computer scheduling model, online or via a Smartphone App, or soil moisture sensors.
UGA Extension has developed a quick and easy irrigation scheduling guide that is laminated and contains the four major row crops grown in Georgia. The guide can be downloaded at https://extension.uga.edu/publications/detail.html?number=C1189.