Building the Seed Bank

By Maggie Gaddis:

Now is the time to think about starting next year's garden from seed. As summer flowers senesce, keep an eye out for the right time to harvest the seed. After the flower fades, the seeds mature. The right time to collect seed is the last minute before you think they will blow away or fall off. The seed pod will be brown and perhaps cracked open, but not fully open. Some of the easiest native flowers to collect from include Rudbeckia, Solidago, Cleome, Liatris, Penestemon, and Ratibida. Collecting is fun on evening walks around the neighborhood (ask neighbors for permission). Check with your local open space managers for regulations on seed collection.

Growing native seeds in a greenhouse is a challenge because many require periods of cold (stratification) or physical weathering (scarification). It is much easier to move the seeds to their garden homes now and let the weather take care of the preparations. Likewise, preparing seed for storage involves numerous steps to isolate, clean, and dry them. Plant the seed now.

I own a gardening business and as a result, I have buckets of seeds from deadheading, lots of little seedlings that get out of place, and very little time to nurture the orphans. The picture below is my plant orphanage, a wild flower garden for my bees. It’s not all native, but it all started from seed or little seedlings with the exception of a peach tree we planted from a pot. The echinacea in the center was planted squirrel-style; I dug a little hole last Fall, dropped a spent flower/seed head into it and covered up. Voila! It is an echinacea plant this year, a factory of seeds with which to inoculate other garden areas. I don’t clean them; I put whatever plant material came with the seed into the ground and cover it up.

The same simple process is effective with grass seed. In the fall, I collect Schizachyrium scoparium (little bluestem), Andropogon gerardii (big bluestem), Bouteloua gracilis (blue grama), Bouteloua dactyloides (buffalograss), and Oryzopsis hymenoides (Indian ricegrass) seeds and spread them around in my garden beds, cover them with soil, and hope for the best. Now is the time to purchase native seed in bulk for use in the same fall planting application. The monsoon season of the late summer is best because, ideally if it's a moist monsoon, some seed will germinate and begin to establish this year. Next year you will have second-year plants and more seed to establish the area. If it gets into September, wait to spread the seed until you hear it's going to snow. Spreading the seed before a snow reduces herbivory and helps establish good soil-seed contact. 

Building the seed bank is about delayed gratification and extended plant observation. Sometimes seeds don’t come up. Then they come up next year. The point is, you should always be feeding your garden with seeds. What is missing is a seed bank. We follow the same mantra in the vegetable garden. Every interspace has cilantro, savory, forget-me-nots, lettuce, borage, chives, marigolds, basil and spinach seeds lying in wait or growing now…because the time is right. We want the interspaces to be filled with herbs, flowers, and greens that we like to use and that produce flowers for the bees. This is how the wildland ecosystem works. There is a time and a place for all species, but if the seeds are not in the soil, there is no opportunity to establish the community.