The Texas Cool Germination test was developed specifically to test cotton seed under cool soil temperature conditions. This germination data is NOT required on the state seed tag, but many seed companies will provide this information. The state seed tag reports Standard Germination data and it is performed in a different manner. It is usually guaranteed on the seed tag at a minimum of 80 percent.

Texas Cool Test data are obtained from a test conducted at 64 degrees Fahrenheit with seedlings counted after 7 days. Higher Cool Test data indicate higher vigor under temperature-stressed conditions. If the Cool Test data for a specific lot of cotton seed is known, then potentially more vigorous seed lots can be identified. This can be used to determine the planting sequence and possible planting date. Producers should begin planting with higher vigor seed under cooler temperatures and finish up with lower vigor seed under warmer temperatures. Planting conditions for rapid germination and emergence include:

  1. high quality seed with good to excellent Cool Germination Test data (>60 percent)
  2. a favorable 5-day forecast                         
  3. minimum air temperature of at least 50 degrees
  4. maximum air temperature of at least 80 degrees
  5. plant into a firm, moist seedbed 1 to 2 knuckles deep
  6. proper and uniform seeding rate of no more than 4 to 5 seeds per foot in 40-inch rows.

Imbibitional chilling injury occurs when cotton seed is subjected to cold conditions during the first 2 to 3 days after planting, or during the time when the seed is imbibing moisture from the surrounding soil. Cotton seed contains lipids which must be converted to energy during germination. The cell membranes must develop properly. Soil temperatures 50 degrees or below around the seed can damage seedlings during this time. Soil temperatures of 41 degrees or less may kill or severely injure the seedling.