Two to three cotton plants per row foot is generally accepted to be an acceptable final plant population in 30- to 40-inch rows. To achieve this population, seeding rates should be slightly higher due to less than 100% germination. Most cotton seed sold will have at least an 80% germination reported on the bag. This is the result of the warm germination test. Field conditions, however, are typically more adverse than laboratory tests. The cool germination test can approximate adverse field conditions and is a measure of seed vigor. Results from the cool germination test are not reported on the bag but can be obtained from the seed company. Growers are urged to find this information.
Being aware of the results of the cool germination test is more important than determining what is actually a good or bad cool germ. For example, a seed lot with 85% cool germ is more vigorous than one with a 65% cool germ. If the 65% cool germ lot is planted in good, warm conditions, however, overall germination is likely to be as high as the 85% lot. Under adverse conditions, the 85% lot is likely to germinate at a much higher rate than the 65% lot. A somewhat arbitrary division of the cool germ test results is shown in the following table:
| Cool germination % | VIGOR |
|---|---|
| >80 | Excellent |
| 65-80 | Good |
| 50-65 | Acceptable - Use special care |
| <50 | Poor - most companies will not sell this seed |
Remember, a cotton seed is a living organism that is used as delivery mechanism for genetic traits, transgenic technology and often seed treatments. Care should be taken to preserve seed quality and plant high-quality seed to ensure adequate plant stand.
