Easy Seed Saving with Promiscuous Pollination

by Irena Hollowell

Mineral, VA 

I’m sure many gardeners consider saving some of their own seed, but then feel like it would be too complicated. I’m guessing the main deterrent, for gardeners who have learned something about seed saving, is what we hear about isolation distances. Southern Exposure, for example, has for many years recommended that when home gardeners save their own seeds, they isolate their seed crops from other varieties in flower of the same species by at least 5 feet for lettuce, 40 feet for peppers, or 300 feet for various crops including corn, okra, and squash. For those gardeners who can’t isolate with distance, we describe methods including hand pollination, isolating in time, and isolating with physical barriers like row cover.  Without such isolation measures, it’s generally likely that pollen from one variety will reach the female flower parts of another variety, and that some offspring will have mixed characteristics of both varieties. With such isolation measures, it’s quite unlikely, but often still conceivable, that some offspring will have mixed parentage.

This post is a rare plea to go ahead and save seed, if you want to, regardless of how close your plants are to others of the same species.  Offspring with mixed characteristics are not forbidden in your garden. It is not wrong to let them grow. You might prefer to have a more predictable garden, or you might relish the surprises.

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Nigerian Molokhia

Here’s a little story of how I first began to stray from the gospel of isolating varieties. Rushdat Hale, a Nigerian gardener living in the US, shared seed with us for a Molokhia (a.ka. Egyptian Spinach) from her home country. I planted it in spring of 2018, and wrote to her that summer: “In our trial patch, the variety we got from you has two distinct leaf shapes. As far back as you can remember, has that variety always had both types? Do you know if it was already that way when it was brought over from Africa? Please write back to me to tell me what you know about the variation in the Molokhia.” She wrote back: “I’m surprised you’ve noticed only two leaf patterns. Back home they don’t separate varieties.”

I wrote back, “I find it very interesting that in your home country (and maybe most of your home continent?) varieties don’t get separated even when folks are saving seed. I wish I had a better idea of how widespread that kind of seed-saving was in countries like this one, as well, before there were many seed companies. I think there are some significant advantages to doing it that way, including in terms of adaptability to unpredictable growing conditions. But, it’s generally not the way varieties are stewarded at companies like ours.”

Over the course of the past two years I have thought more and more often about this conversation, and I feel increasingly confident that it has only been in recent decades that anyone has come to have the expectation that seed-savers will isolate their varieties.

I estimate that seed-saving philosophies like Rushdat’s are still common in most rural parts of the world, and also among many Americans who learned how to save seeds from relatives who learned how to save seeds from previous relatives. I expect that adherence to isolation distances is common only among people who have learned to save seeds from books, or from seed companies. I’m sure the academic-style learners (and teachers) are, as a group, much whiter than those who have learned to save seeds from their relatives. As with many other aspects of non-white cultures, I see a risk of unintentional disparagement if we say that things must be done the way we’ve learned in formal settings.

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There are plenty of other examples of traditional seed-saving practices that are quite different from what’s generally recommended in modern times. Will Bonsall maintains a type of flint corn from Byron, Maine.  The people of Byron had a tradition of mixing their corn: When a farmer was on his way to visit a neighbor, he would take a pocketful of corn from his corn crib, and during the visit he would drop those kernels in the neighbor’s crib.  The neighbor’s strain of Baxter Sweet Corn was probably slightly different, probably a little better adapted to that neighbor’s own microclimate. As modern geneticists would say, the mixing helped ensure that the farmers’ corn did not become too inbred. I wonder how often pocketfuls of Byron corn made it into corn cribs of farmers who are not from Byron.  I wonder what kinds of conversations those farmers had about this practice.

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Suzanne Ashworth decided to write Seed to Seed because, before the 1991 first edition of her book, “a comprehensive guide to saving vegetable seeds on a small scale was not to be found.” She also wrote that “The only isolation distances ever published for some crops are the recommendations made by commercial seed producers.” And so she provided those distances as guidelines in her book. She also wrote that “Isolation distances are highly site specific and depend on many factors such as plant population size, pollinator population density, presence of alternative insect forage sources, geographical barriers, vegetation barriers and other habitat-related factors. These commercial recommendations should be viewed as maximum starting points for individualized experiments to determine isolation distances that would be more appropriate for specific garden sites.”

Southern Exposure was one of the first sources to make specific recommendations about what minimum isolation distances home seed savers should use for various crops. We’re still making those recommendations, including with this very popular Basic Guide to Seed-Saving (pdf). I’m confident that the primary messages my coworkers and predecessors wanted to convey with this advice were: 1) You don’t absolutely have to isolate by very large isolation distances like those cited in Seed to Seed and 2) Isolation distances do matter, and they vary a lot from crop to crop.

However, I detect an assumption throughout Seed to Seed, and also in resources provided by my company, that the goal of the seed-saving gardener is generally to maintain varieties in their original forms, or at least fairly close to those original forms. I also detect an assumption that when we sensibly veer off the path of simply maintaining a variety, we do so by choosing and then enacting distinct changes in the variety, such as by crossing it with a carefully chosen second variety, or by selecting for earliness, sweetness, disease resistance, or keeping quality. This is generally considered to be more complicated than simply maintaining a variety in the form we receive it in.

NT Half-runner bean pods at various stages of maturity

For many seed savers, genetic purity is a perfectly good goal. For example:

  • If you’re growing seed to sell to a seed company, that seed company has every reason to want to know that the description in its catalog will continue to be an accurate description of the variety.
  • If your great-aunt gave you a bean variety that her family grew for many decades, you may have personal reasons for wanting to keep it like it was when you got it.
  • Even if you don’t expect to share it with anyone, you might feel it’s quite essential to keep your corn from getting cross-pollinated with GMO corn.

But genetic purity does not need to be a goal of every seed saver.  Some even consider crop genetic purity to be a disadvantage.

Researchers, agronomists, and others have generally used the term “landrace” to describe varieties like Rushdat’s Molokhia.

The landrace gardening movement, as in this article from Off The Grid News and on this permies forum thread, encourages gardeners to create their own highly diverse landrace varieties by planting a mixture of many different varieties, saving the seed, planting it the next year, and repeating year after year.

Perhaps the foremost and most vocal of these gardeners is Joseph Lofthouse, who lives in Utah, in a climate where most commercial varieties of most crops, just won’t yield a harvest at all. As Joseph points out, “The plant, the farmer, and the society are all intimately entwined in landrace growing.”  He has developed many different landrace varieties that are available for sale, mostly through the Experimental Farm Network.

Tomato isolation plots

As Joseph put it on the aforementioned forum,

“Starting with the same seed, someone that grows in a raised bed might end up with genetics much different than someone that grows in the dirt. Growing with lots of mulch might result in different genetics than growing in plain old dirt. One time when I trialed a lot of new tomatoes, I noticed that plants from my saved seed grew differently… Because my vines tended to arch upwards to keep the tomatoes out of the dirt… Since I don’t stake tomatoes I only save seeds from tomatoes that are not touching the dirt and rotting. So I had inadvertently been selecting for genes that keep the tomatoes suspended in the air without staking. There’s so many nuances like that… The plants adapt to everything around them… Even my customers at the farmers market are influencing the genetics of my plants due to their eating preferences, and the seeds they return to me, and the seeds they gift to me.”

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You don’t need to choose between these two goals – genetic purity and landrace gardening – even for one crop. One intermediate route would be to save seeds from your favorite varieties without worrying about whether they’re cross-pollinated or not. Of course, the more widely you share the seeds you’ve harvested, the more likely they would get into the hands of someone who assumes that genetic purity is everyone’s goal, so if you sell or trade seeds from plants which are promiscuously pollinated, I’d recommend making that pollination method clear in your descriptions.

If you are going to save seeds without aiming for genetic purity, here are two situations to keep in mind where crops that we call by different names are in fact in the same species, and can cross with each other:

  • Most zucchini, most pumpkins, some other winter squash, and most small gourds are all in the species of Cucurbita pepo, and can cross with one another over significant distances.
  • The species Brassica oleracea includes broccoli, cauliflower, cabbage, kohlrabi, brussel sprouts, gai lan, and some kale. These can cross with each other over significant distances if they flower at the same time.

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A view from one of our pepper tastings

In New Mexico, it is common for farmers and communities to maintain their own varieties of chili peppers, such as the Hatch Valley chilies, and to exchange seeds freely, but to tell recipients that the peppers won’t be the same if grown in a different place, and should not be called by the same name. Terroir is a prominent aspect of this line of thought. New Mexican farmers giving away chili seeds may encourage the recipients to those peppers cross with other peppers, save the seeds, and develop new varieties unique to their own locations.

This year I might save seeds from the section of our gardens where I’m growing and comparing 40 kinds of peppers, including sweet and mild and hot (but not extremely hot), belonging to four different pepper species.  I wonder, should we offer the mix (or part of it) for sale?

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So why aren’t diverse landraces more common among heirloom vegetable varieties?

It’s largely because, while those heirloom varieties were being developed, the farmers growing them didn’t have access to a whole lot of seed catalogs. So they basically just grew one variety of each of their crops, with occasional, sporadic introductions of new genetics through various means. Over many generations of plants, when new genetics don’t get introduced, a landrace variety will tend to stabilize. The plants in it will become more similar to one another.

A mix of winter squash varieties on Kurikindi Farm, Ecuador

Also, landrace heirloom varieties might be more common than we tend to think, especially in crops that cross-pollinate over large distances. With the right pollinators, it is possible to see at least some cross-pollination between squash varieties even at ½ mile. At Southern Exposure, we’ve heard about a few highly variable landrace varieties of squash from the Southeast – and I’m guessing there are many we haven’t heard about.

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Nowadays, most breeders aim for uniformity.  On large commercial farms, uniformity is essential. These farms are aiming to harvest the largest possible amounts of produce with the smallest possible amount of labor, which includes the smallest possible number of harvests. It also includes eliminating any need to pay attention to any differences between the plants. Even in a home garden, uniformity has its advantages. But in a home garden, you probably would prefer to spread your fresh produce over the longest possible season. And you might even prefer, when you plant one kind of squash, to get fruits that vary in flavor, shape, and size.

In my future presentations about seed saving, I’ll mention landrace seed-saving philosophies, and I’ll temper the recommendations I give about isolation distances.