Seed Saving of Cultivated Edible Crops

This week we held our monthly potluck at Whole Foods on St. Francis. Two free classes were involved and the crowd was pleased with the information provided. We wanted to post it online for more to be educated. Pablo Navarot wrote the following information for seed saving. We hope to see everyone at our seed exchanges in February and March of 2013.  On November 3rd, Pablo will present a TEDx talk regarding seed saving.

Conserving Cultural and Ecological Heritage

As gardeners, we inherit an impressive legacy through through seeds.  A great example is corn.  Corn in its present form never existed in nature.  10,000 years ago people began cultivating a hybrid between teosinte and another tropical grass of the Americas.  Corn does not exist purely in nature; the kernels can’t set root in soil without someone peeling back the husk and removing the kernel from the cob before it will germinate or rot.

Seeds are imbued with a memory of the environment that they are grown in.  Tropical chili peppers have adapted to New Mexico’s intemperate climate, whereas chili strains adapted to other regions may not be fit to germinate and produce prolific fruit when introduced into a high altitude Southwest garden.  In biology, this may be described as an example of an environmental selection pressure.

The grower’s choice of seeds to save represents a cultural selection pressure (selective breeding).  In commercial seed production, the diversity imbued in seeds is bottlenecked because the grower (who may have a large operation in an environment much different from the home gardener) selects seed from parent plants that did not succumb to crop failure and possess marketable traits.  This seed stock may not include specimens adapted to overcome the ever-evolving garden pests and pathogens of a particular region.

Local seed exchanges offer non-commercial sources of seed that have not only proved successful in that particular region, but they also reflect the selection pressures of multiple growers.  Seed exchanges foster crop diversity through the complexity of its networked architecture and support a continual evolution of crops; an average gardener can both grow heirloom seed for the next season and foster a unique lineage of seeds for their grandchildren’s generation and beyond!

Initial Acquisition
It is important to start with seeds or plants that will reward you for your seed saving efforts.  Local seed exchanges, family heirlooms, online sources, nursery plants, commercial seed sources, farmer’s markets, and grocers will all offer the home gardener sources for starting seed lineages.  Avoid F1 (a.k.a. ‘hybrid’), and genetically modified seed.

Heirloom, Landrace, and Hybrids
Heirloom seed may be defined as seeds that can produce crops of particular traits over multiple  generations.  Landrace seed is similar to heirloom stock but it is associated with a particular region; Chimayo chili may not produce the same fruit when grown in a greenhouse in Maine.  Hybrid, or ‘F1’, seeds are crosses between two (often cloned) parent plants that reliably produce an offspring with particular traits but subsequent generations may not resemble the traits of the initial hybrid or first generation (F1).

Cloning – Division, Stem Cuttings, and Layering
Plants often clone themselves in nature or they can be cloned, but since there is no flower pollination, there is no increase in genetic diversity.  For example, garlic cloves are genetically identical to its parent plant.  However, the bulblets harvested from matured garlic flowers are genetically recombined, and may have cross-pollinated with other garlic strains; the resulting garlic plants may not be the same as the mother plant.  Planting garlic cloves, potato tubers, or separating clumps of chives are all forms of ‘division.’  Some plants such as basil, mint, rosemary, thyme, or tomatoes can be cloned by taking a piece of stem and placing it into a peat-based potting soil exposed to super humid conditions (like under a plastic food storage bag).  In low light, the stem will grow roots in about 3 weeks; rooting hormone is not necessary for the above mentioned varieties.    Layering is when a branch is covered with soil to root then cut from the parent plant to produce a new cloned plant.  Many breeders use a combination of cloning and cross-pollination to produce new crop varieties.

To produce your own seeds, be mindful of the pollination process.  Does the plant require isolation from other strains or need to be grown as a large group?  Can this isolation be accomplished by using a barrier like agricultural fabric, physical distance, or simply insuring that different strains are not flowering at the same time?  Refer to sources such as or for additional information, but remember that there are crops such as common beans that typically do not require isolation of any kind to reproduce true, they most often self-pollinate.  And in some cases like cilantro, it can’t self-pollinate and requires bees or other insects to do the job for them.  Often cross-pollination may not significantly compromise the the integrity of the lineage; in nature cross-pollination is important to keep populations strong.

Processing Seeds
Allow seeds to age on the plant as long as possible before saving them.  Mature, robust seeds will be an ideal fit for germination.  As chefs, we often harvest cucumbers, zucchini, and peppers (green) before they have matured fully, the seeds from these young fruits may not be viable.

For wet seeds like melons, pumpkins, tomatoes save seeds from the cutting board by placing them onto a dry napkin and write on the napkin the name of the variety and year.  One can also place them in a jar of water for a short period of time to allow the coating to be consumed by yeast, the seeds that fall to the bottom are the ones that are still alive.

Cosmos and arugula seed is a favorite food for birds in Santa Fe.  Plan to sweep remaining seeds off of the ground to collect them, or allow the seeds to be stored in the mulch and left in the garden.

Seeds that are not found in fruits such as basil or kale can be collected by harvesting the whole stem, tied into groups and completely dried when hung upside down.  Chop the stems into a fine plantable hay using long bladed shears; threshing (to break the seed from the chaff) and winnowing (blowing the chaff away) is optional for most crops.  Thresh by wearing dishwashing gloves or stomp on the stems over a tarp, and winnow with a fan while agitating the mix. The advantage of planting seed hay is the gardener has a visual clue as to what areas have been sown and to avoid the process of winnow seeds, the disadvantage is that the seeds will not be evenly distributed in this hay and seeds storage requires greater space.

Keep seeds in a dry place protected from mice and insects; envelopes and plastic bags are efficient but don’t work well in the garden when windy.  Jars with lids are ideal for harvesting and planting, but are best when not airtight.


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