Seed Viability & Germination

Seed Germination

Just like the plants in your garden, seeds need the appropriate amount of light, moisture, oxygen and the right temperature to germinate. To maintain the viability and vigor of seed, it is essential to make sure they are stored in the appropriate conditions. Ideal seed storage requires very low humidity and temperature approximately 40-50˚F and 25-35% relatively humidity.


Seed Viability Test

Regardless, of how perfectly you stored your seeds, if you didn’t use them all in their first potential growing season, you will want to perform a viability test. To do this, simply place a specific number of seeds between two rolled up and moistened paper towels then place them in a plastic bag and seal. Make sure the seeds remain moist and warm (70-75˚F). If the germination rate is less than sixty percent, don’t waste your time, money and energy sowing them. If it is less than one-hundred percent. But still an acceptable range, just sow extra to account for the non-viable seeds.

Germination Conditions

Many seeds readily germinate in warm, moist environments. However, as with any plant species, many have different and specific requirements for optimum germination. For instance, most parsley varieties require darkness for germination, so it is best to check out what the seed packets says concerning ideal germination environmental conditions for that seed variety.

When choosing the best media for seed germination make sure it has good drainage, fine texture, a low soluble salt level (Electrical Conductivity EC), and of course, is pathogen free.

The ideal soil temperature for most seeds to germinate is between 70-75˚F. If the soil’s temperature dips below 70˚F sluggish erratic germination will occur.

In general, light requirements for germination are relatively low. However, some smaller seeds need to be sown on top of the soil to receive adequate light, while a few species prefer darkness for germination.

Important water requirements include uniform application and low water electrical conductivity. High water-EC will cause germination to become sluggish and sporadic, and also leave the seedlings more susceptible to disease. Inconsistent watering, where the media is able to dry out between applications will also damage or kill the seedlings.


Transplanting can make or break your crop literally. If you are starting your seedlings in open flats then you can transplant after they have grown their first set of true leaves. If transplanting out of anything larger, it is important to make sure you have given the young plants time enough for their root structure to fill their current pot. If you attempt to transplant before the roots have filled the pot, the “root ball” will crumble and your plant.  If your transplants recover, growth will be stifled, it will ultimately be a sluggish producer and a waste of space and time in your garden. Conversely, if you wait too long to transplant your plantlets you can face a whole other host of problems including stunted growth; stem elongation; disease susceptibility; precipitate flowering; and, ultimately a lower yield.  So pay close attention.


Dole & Wilkins, Floriculture: Principles and Species. New Jersey: Pearson. 2005.