May planted cotton should be squaring and getting close to bloom, if it’s not there already. Bloom usually occurs 9 weeks after planting and water requirements begin to approach peak demand during this time. Water is critical during the “first flower to first open boll” phase. This growth stage takes place between 9-17 weeks after planting. During this stage, cotton may require up to 1.5 inches of water a week or .2 inches a day. The Soil Water Holding Capacity (SWHC) for most of our soils is about 1 inch/foot of soil. The crop can only access water where it has roots and of the SWHC only about 50% of the water is plant available. Therefore, a cotton plant with 18-inch rooting depth will have access to .75 inches of water at field capacity, meaning that it will require irrigation every 3-4 days minimum. This is based on rainfall and irrigation efficiency during this stage. Don’t let your cotton experience water stress during this stage as it can reduce plant growth which in turn reduces the number of fruiting positions. Weather plays a big part in this. If it’s cooler and cloudier you may not need to water as much as you would when it’s sunny and hot. Credits to Cale Cloud, Extension Agent, David Hall, Extension Water Educator, and Wesley Porter, Extension Precision Ag, and Irrigation Specialist.

This graph should give you a good idea of weekly water requirements through July if you planted your cotton in April-May.

Just so you have an idea of where the state stands as of the end of June below is the current GA Drought Monitor Map. Currently, we are not in a drought anywhere in the state. https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?GA.

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