Telling the Difference Between Good & Bad Seeds

Germination Test

• A simple germination test gives you an indication of whether your seeds are good. Place 10 seeds on a moist paper towel and roll them up in the towel. Place the towel containing the seeds in a plastic bag and leave them at room temperature for a week or two. You can estimate the germination rate from the number of seeds that germinate, and use the estimate to determine whether the seeds are good or bad.

Conditions

• Some seeds need special conditions in order to germinate. Read the back of the seed packet to find out if the seeds have special requirements. Some need light to germinate, while others need complete darkness. Temperature requirements and the length of time required for germination vary. Try to accommodate any special requirements when testing the seeds. The North Carolina Cooperative Extension's Seed Germination resource gives the basic germination requirements for a number of plants commonly started from seeds.

Interpreting Germination Test Results

• After a week or two, unroll the paper towel and count the number of seeds that sprouted. Multiply the number of sprouting seeds by 10 to get an estimate of the germination rate. For example, if eight seeds germinate, multiply eight by 10 to get 80, indicating an 80 percent germination rate. A germination rate of 80 percent or more is good enough to use the seeds as you would fresh seeds. Keep in mind that this is a rough estimate. Performing a germination test on 50 to 100 seeds gives a more accurate germination rate, but home gardeners don't usually have this many seeds to spare.

Using Seeds with Low Germination Rates

• You can use seeds with a low germination rate if you adjust the rate at which you sow the seeds. When starting seeds indoors, plant several seeds in each pot. Outdoors, sow them close together. When the seedlings emerge, thin them to the recommended spacing by clipping or pinching them off at ground level. If the seeds have a germination rate below 50 percent, mix a few of these seeds with fresh seeds and space the seeds as recommended.