Cool germination is a measure of the vigor of cotton seed and an estimate of its ability to emerge under less than optimum conditions in the field. Cool germination is conducted in the laboratory at temperatures that attempt to mimic actual field conditions. The germination given on the seed bag is called standard germination. Standard germination is conducted at higher temperatures and is not necessarily a good indicator of seed vigor, especially if the seed is planted under less than optimum conditions.
Select the highest quality seed possible. High quality seed is critical to success in the first forty days and the crop’s ultimate performance. Vigorous germination and emergence is best because it narrows the window for seedling diseases and minimizes the impact of pests. In addition to the standard warm germination test, a cool germination test is recommended. When cool germination and warm germination numbers are added together, high quality seed will have a vigor index of at least 160 (i.e., a warm germination of 90% plus a cool germination of 70% equals a vigor index of 160). Early planting into cool soils requires a high vigor index. When planting early, plant the best vigor index available in the variety you are planting.
