How do you test seed viability?
Written by
Paul Reynolds
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Testing seed viability to save wasted time and effort in your garden is worth the time and trouble. There are three basic methods available: water test, germination tests, and tetrazolium tests. Each test determines the viability of the seeds in different ways. The water test determines the buoyancy of the seeds. The germination tests actually cause the seeds to sprout. The tetrazolium test shows the activity of the cells in the seeds. Each to be chosen depends on what kind of seeds you have and the instruments you have available.
The water test is best suited to larger seeds that include beans or corn. The seeds are immersed in water, and their buoyancy is noted after 15 minutes. The most viable seeds sink because they are compact; the hollow seeds float. The exceptions are corn, which sometimes floats even if sound, because of the air pockets found in all seeds. Results must always be verified by some other means.
Germination testing reveals real potential for growth by utilizing items commonly found around the house. Put the seeds between damp paper towels placed in sealed bags. Maintain temperatures between 70°F and 80°F for successful sprouting. This method can be used for the majority of seeds, but is not suitable for those that germinate very slowly. Be sure to mark the bags during the test, so there is no confusion with any taken during the test.
The tetrazolium test employs chemical reactions to reveal living tissue. Seeds are soaked in tetrazolium chloride solution. This causes the living tissue to become inflamed and appear red. This laboratory method requires careful dissection; therefore, safety precautions must be taken. Laboratory gloves should be worn, and good ventilation is necessary. The results of this test are visible within 24 to 48 hours and show positive cellular activity.
Water Test
- Best for: Large seeds like beans and corn
- Time needed: 15 minutes
- Accuracy: Moderate, confirm with germination test
- Tools: Bowl, water
Germination Test
- Best for: Most vegetable and herb seeds
- Time needed: 2-14 days
- Accuracy: High, shows actual sprouting
- Tools: Paper towels, plastic bags
Tetrazolium Test
- Best for: Scientific precision
- Time needed: 24-48 hours
- Accuracy: Very high, reveals cellular activity
- Tools: Chemicals, dissection tools
Select the testing method that best suits your specific seeds and situation. Water tests allow speedy preliminary checks for large seeds. Germination tests give you reliable evidence of growth potential. Tetrazolium gives scientific breeding accuracy on valuable seeds. Testing ensures that every seed planted has the maximum growth potential. Start your viability tests today.
Read the full article: Seed Viability Test Guide: Ensure Your Seeds Grow
