Warm Germ - Paper Towel

The warm germination test is the standard test used to assess viability of seed lots. The seed is germinated in nearly ideal conditions, and the result is the germination percentage reported on the seed tag of commercially sold seed, as required by the Nebraska State Seed Law. Ideal temperature, relative humidity and light vary depending upon the plant species being tested. The materials needed to conduct the warm germination test of large-seeded crop species, such as corn and soybean, are:  wetted thick paper towel, wetted thin paper towel, a seed counter tray, and a container to hold the seed.

Seed from the seed lot to be tested is placed in the container.

The seed is poured into the counter tray.  Seed is placed into each hole, and the excess seed is poured off.

The seed counter tray is placed on the wetted thick paper towel.

A sliding drawer is pulled, dropping 50 seeds on the paper towel.

Note that when the seed counter tray is removed, the seeds are evenly spaced.

The thin wetted paper towel is placed over the seeds and the thick paper towel, and the edges of the paper towels are pressed together to seal them.

The bottoms of the towels are folded to keep the seed from rolling out.

The towel is rolled up. This facilitates handling and helps keep the towel from drying out.

The seed lot number is written on the towel for identification. Special pencils that are capable of writing on wet paper are used.

Intermediate sized seed species, such as wheat, can be counted and placed on the paper towels using a vacuum plate. This reduces the time required. Seed are placed on the vacuum plate (tubes not showing), and each vacuum point holds a seed.

Extra seed is poured off, and seed remain where the vacuum pressure is present.

The vacuum plate is laid on the thick wetted paper towel, the vacuum is released placing the seeds uniformly on the paper towel.

The paper towel is rolled and marked as done for the large-seed crop species.

The germination chamber controls temperature, relative humidity (humidifier at bottom) and light.

The portable humidifier used for humidity control is similar to one used in bedrooms during the winter.

Temperature and relative humidity are recorded inside the germination chamber .

Temperature settings vary depending upon ideal temperatures for germination of seed from different plant species.

The rolled paper towels are placed plastic sacks to prevent drying, placed in a germination chamber with the proper temperature, humidity and light.

After the prescribed time (often one week), the towels are removed from the chamber.