We mentioned seed viability recently, so let’s dig into it! Seed viability deals with the length of time that a seed can still germinate and become a seedling. Essentially, how long they are viable.
Different types of seeds will have differing levels of viability. Some last a short time whereas others last a long time, typically ranging from a single year to upwards of five (or more) years. This variability is usually due to the type of seed, but it can also be influenced by things such as seed storage (temperature, humidity, etc.) and biological things like the genetics and health of the parent plant.
Now, it’s important to know that seeds don’t just suddenly expire. Seed viability is better described as a hill, not a cliff. As you push further and further into the expected lifespan of a seed, you’ll simply observe lower and lower germination rates of those seeds.
If you have some older seeds that are past their estimated viability date, they aren’t necessarily trash. But, you may need to sow greater quantities of that seed to get the desired quantity of successful plants. When we notice exceptionally poor germination, usually less than 50%, we make a note in our garden journal to replace that seed the following season.
You can also test seed viability. For us, we simply grow far too many seeds and plant types for this to be feasible. So, we just kind of “wing it” based on the seed’s age and do our seed replacement corrections from season to season. Sure, this does sometimes mean we “screw up” and don’t have the plant counts we want. But, as a general practice, we over-sow the quantities of seed in order to better meet our transplant production goals.
It’s also important to remember that there are many causes of germination failure outside of just seed viability. We’ll be talking about that in the future. But, in the pre-season, our main goal is to try and make sure our seed collection is “up to snuff” for what we expect to do with it this season.
We do have an article that goes into a lot of depth on seed viability, including viability charts for most common vegetable, herb and flower seeds. We also detail seed viability testing procedures. We thoroughly revamped it this year, too, as our former version wasn’t quite up to our desired quality standards for our articles. You’ll find that link down in those comments!
Bonus! We also made a video about this topic!
