Sweet Pea Seed Saving
If you’re new to saving seeds, the best advice I can offer, is to follow the natural rhythm of the plants. I know, that’s a bit vague, but hear me out.
First, save seeds from your healthiest, most robust plants or stems, this is ideal for the healthiest stock seed. Seeds remember the growing year, we call this adaptation. Adaptation includes everything about the growing conditions.
While some seeds will continue to mature off the plant, not all do, and not as well as they would on the plant. So letting them mature as much as possible on the plant, and catching them just before the plant drops/shatters them into the soil, will give you the highest quality seed. This is the moment the plant deems them ready, listen to your plants, they know what they are doing!
Sweet peas fall in the category of not maturing much or well off the plant. (It’s like cutting a dahlia bloom in bud stage and hoping for it to open fully in the vase.) harvesting them early will give you a higher rate of hard seed, immature seed, and lower germ rates. So while waiting can be hard, waiting to harvest till the WHOLE pod feels like sand paper, and you feel tension in the pod, like it might explode in your hand (and it might!), that’s the ideal moment to harvest a sweet pea pod. I like to then store them in a paper bag (top folded and clipped shut to keep exploding pods/seeds contained) in a warm dry space, for a couple of weeks, to dry down (dry out any remaining moisture, as moisture in storage leads to mold.). And then the cleaning begins. If you’re saving for yourself, remove the pods and any other plant material. And then save the biggest, fullest seeds. Small and highly deformed seeds can be genetically compromised - not always, but personally I don’t like risking it.
“For a seed to achieve its greatest expression, it must come completely undone. The shell cracks, its insides come out and everything changes. To someone who doesn't understand growth, it would look like complete destruction."
— Cynthia Occelli