Thoughts on Cotton Planting – Soil Temperatures

By Keith Edmisten

The soil temps have not looked very good for the last few days. Optimum would be to get up to 65 or more degrees at 10 a.m. We would at least like to see it get near 65 degrees sometime in the morning hours. As you can see below, we only reached 65 degrees late in the day on the 25th. The forecast is looking like that should start to change for the better this week.

Is 65°F at 10 a.m. a hard and fast rule? Well, some states say by 8 or 9 a.m. or suggest a slightly different depth, some say it should be at 65 degrees for several days before you plant, so there is no hard and fast rule. When I arrived in Alabama, I was engrained with the Mississippi “rules.” I went to South Alabama and told them that they could plant earlier than they were planting based on my analysis of their soil temperatures. A wise old grower took me aside afterwards and said Keith, yes we could plant earlier, but we have learned not to due to hurricanes. Lesson learned? No way. I went to North Alabama and repeated my spiel about 65 and there again a wise old cotton grower took me aside and said that if we do that we may never get our cotton planted. He also told me our well-drained red soils warm up faster during the day than the soils you are used to in Mississippi. These wise Alabama farmers taught me that cotton production is too complicated to totally depend on hard and fast rules and formulas.

Over the years I have learned that soil temperatures are very important, sure 65 or more degrees is ideal, but there are other factors that influence successful stand establishment. There are factors that can help result in successful stand establishment besides relying on soil temps alone.

When I consider the phone calls I have had concerning planting when cool night is predicted, I make the same recommendation to several calls, in this instance let’s say I recommended against planting. It was not unusual when I follow up with the growers or their agents that some went ahead and planted, some realized an acceptable stand and some did not, Why is this? I think this points out that there are other mitigating circumstances that relate to cool germ, seed size, soil moisture levels, planting depth, soil temps going into the cool snap e.g.

Why am I telling y’all this? We will be publishing planting conditions forecast for the next several weeks. and hopefully many of you will use our Cotton Planting Decisions Calculator. The recommendations in our charts are fairly conservative. You may choose to accept more risk. Knowing your cool germ, considering seed size, planting depth, soil moisture, and drainage capacity, soil crusting, likelihood of packing rains and other factors will help you make better decisions when you decide to accept more risk. Let’s face it, planting cotton is always a risk, it is about how much risk you are willing to accept.

A grower could use the Cotton Planting Decisions Calcutor to develop strategy for the day or next two days and then refine that strategy by checking soil temperatures in the morning. In some cases you might want to wait until later in the day as soil temps increase. You can find soil temperatures at Map.