Seeds and Seed Collecting

Some Seeds From My Landscape Plants

I've been meaning to write about seeds and collecting them for some time and my last post made it finally seem like the right time. I make no pretense about where I stand on the issue of planting seeds or plants in a native plant landscape; I waffle a bit in the middle because I collect seed, plant it in flats of potting soil and then add the seedlings to my landscape. After a great many years of planting landscapes of native plants, I've learned that sowing seed directly into bare Florida soil almost never produces satisfactory results. There are just too many moving parts so to speak, and my bare-soil areas are always colonized most with aggressive lawn weeds when I try the direct seeding approach. It seems economical to purchase a packet of seed from a desired plant when you get 50-100 seeds for a few dollars instead of 1 plant for $4-5 and sometimes it is; just not often enough in my experience.
Most of the problems related to seeds have to do with their biology. We often think of them as inert objects when they are complicated living organisms. Seeds contain the baby plant and this embryo is not much different from an animal embryo. It is alive and has a base metabolism. To stay alive, it has to feed and breathe. The embryo inside the seed slows these needs down to a certain extent while it waits for just the right stimulus to germinate, but there is a limit to how long it can wait and do this before it expires. I read from time to time about discoveries of seeds in ancient tombs that are still viable and from which formerly-extinct plants are brought back to the living world. These examples are fascinating, but extremely rare; certainly out of the norm. Plants adapted to really harsh conditions often evolve seed-germinating strategies that allow them to remain dormant for long periods of time. For example, if a rain event is rare in a desert, seeds requiring moisture to sprout would want to evolve an ability to wait for that rare event. Here in Florida where the weather is pretty favorable to plants year-round, few species need such adaptations. Most of the seed I grow in my home nursery here dies after about 3 months. If I don't plant it within that time frame, I might as well throw it out.
I could extend the life of some of my seed by keeping it cold. As plants are "cold-blooded" creatures, keeping them cold slows down their core metabolism and extends the time period before they run out of energy. I generally don't do this because I sow my seed as soon as it's ripe. It just seems easier that way and I don't have to remember dates and clog up my refrigerator. Chilling dry/mature seed in a refrigerator is not the same as stratifying moist seed that way. Some seed needs to experience a cold period to realize that it is now spring and warm enough to sprout. Cold-stratification generally works best with seed in a moist environment. Keeping seed cold to prolong its viability is best done in a sealed envelope/container that prevents moisture from complicating things.  Envelopes that are hermetically sealed function this way to prolong viability. Envelopes that are simply sealed with a gummed flap do nothing to prevent the loss of viability over time.
If you purchase seed from a seed company, they generally have an expiration date on the envelope. If they don't, be VERY wary of achieving success with those seeds. There are a few exceptions to my 3-month rule, but I've spent a good deal more money on the ones that aren't than the few that are. Blazing stars (Liatris spp.), are one genus that perish rapidly after the seed matures. If you purchase seed in the spring or summer, it is most definitely old and not likely to contain a single viable seed. Purchase seed within a month or so from its typical ripening date and ask to make sure you're not getting last year's seed.
As I've written so many times and in various places, I collect seed from my own plants. I purchase a couple of plants when I can find a nursery that propagates it. This helps keep good people in business. If no one grows a particular plant I want, I collect some seed myself and grow a few plants to collect from in the future. There are just right and wrong ways/legal and illegal ways to go about this and Ill write more about that in a future post.