Test Overview
Duration: Typically 10 days
The Saturated Cold Test is a vigor test used primarily for corn to evaluate a seed lot's ability to germinate and develop following exposure to severe cold and wet conditions.
The test provides a greater level of stress than the Tray Cold Test (Iowa Cold Test) and can be useful for distinguishing differences in vigor among seed lots with similar standard germination results.
Because the test intentionally creates severe stress, results should be considered together with standard germination and other seed quality information rather than interpreted as a direct prediction of emergence under all field conditions.
Test Details
Seeds are planted on a thin layer of soil over saturated germination paper. The testing system is designed to ensure rapid uptake of cold water while saturated conditions restrict oxygen availability around the seed. Together, cold temperature, rapid imbibition, and reduced oxygen availability create controlled stress during the early stages of germination.
Seeds are held at 10°C (50°F) for seven days and then moved to 25°C (77°F) for three days to allow seedling development.
At the completion of the test, seedlings are evaluated and classified as normal seedlings, abnormal seedlings, or dead seeds.
Saturated Cold vs. Tray Cold
Both tests evaluate seed vigor following exposure to cold, wet conditions, but they differ in the type and intensity of stress imposed on the seed.
The Tray Cold Test (Iowa Cold Test) exposes seed to cold, moist conditions in a sand or sand/soil system, providing a moderate stress that incorporates the effects of the growing medium and, when soil is used, naturally occurring microorganisms.
The Saturated Cold Test creates a more severe and highly controlled stress by exposing seed to cold water uptake under saturated conditions with restricted oxygen availability. This combination places greater stress on the seed during the earliest stages of germination and can more sharply distinguish differences in vigor among seed lots.
Sample Requirements
A minimum of 200 seeds are required to conduct the test. Please submit at least 300 seeds to provide sufficient seed for testing.
Additional seed is required when other tests are requested on the same sample.