Seed Testing: Germination and Vigor

Seed germination and emergence is the first step for successful production of most plants. The ability of seeds to germinate (often called viability) and to emerge in soil is the key for plant establishment. Seed testing is commonly used to assess viability (the ability to germinate under ideal conditions) and vigor (the ability to emerge in soil under stress conditions), and to determine the purity of seed lots. These then help plant producers with many management decisions, including determining seeding rates and to avoid planting weeds.

The Nebraska State Seed Law requires that all commercially sold seed lots to have the percent germination (viability), purity and weed seeds to be reported on the seed tag. Vigor tests are used by companies for research in hybrid/variety development, and to understand the ability of seed lots to emerge from soils under stress conditions or to maintain viability during storage. The percent germination (viability) is tested using the warm germination or tetrazolium tests, while the cold and accelerated aging tests assess seed vigor.


  • Describe the methods of conducting warm germination, cold test, accelerated aging, tetrazolium stain, and purity tests.
  • Explain the uses of germination, vigor and purity tests, and interpret test results.

Using these lessons:

In each of the following sections, The steps are explained in words and pictures, many sections end with a link to a movie about the process.