Saturated Cold Test
Duration: 10 days (Seven days cold, three days warm)
The Saturated Cold Test provides an estimate of emergence under more severe conditions. It provides very useful information, but care must be taken that it doesn’t unnecessarily eliminates seed lots that may produce an acceptable field stand under less severe conditions.
Saturated Cold Test
Test Details
A paper towel (germination paper) is wrapped sideways around a plastic grid (“egg crate”) serving to wick water from below the stopper supported grid to two paper towels with a thin layer of soil on them. Prepared trays in a air tight germination cart is placed in 10°C at a minimum of overnight so that seed placed on the soil take up cold water.
Three samples of 200 seeds each are planted on each tray. The cart containing the trays is placed in 10°C for seven days without light and then moved to 25°C for three days. The number of normal seedlings, abnormal seedlings, and dead seeds are recorded. Since there is less growth than in a tray cold test, the analyst must detect finer differences in the seedlings.
Seeds may be turned so that the side of the corn kernel closest to the embryo is down against the soil or they can be left randomly oriented. Seeds being embryo down insures that seeds will start germinating more uniformly as it takes longer for water to reach the embryo of a corn seed that is embryo up. Tests that have seeds embryo down or randomly oriented will produce the same or very similar results, it just takes more a bit more care to evaluate a test with random orientation.