Today we’re going to start to cover the fascinating topic of seed saving. We’ll begin by discussing seed harvesting and then dig a little deeper into the genetic diversity needs of seeds.
Let’s start with me, riding Coco (our beautiful buckskin mare and manure maker), with a big satchel strewn across my chest and adventure in my heart. We’re heading out about a half mile east to a neighbor’s property. What is happening there?
Seeds! There are lots and lots of arugula plants that have gone to seed. I hop down, open my bag and gather the brown pods. (Yes, I’m doing this with my neighbor’s permission.) When we get home, I take the bag to my garden desk and see this:
The pods were so ready to pop, many did so on the ride home. I then scoop the seeds into a strainer so I can separate seeds from bits of dirt (this takes 3-4 sifts) and then pop the seeds into some packets.
This story of seeds is crazier than you’d think because both arugula and kale belong to the brassica family, which is one of the most complicated crops to work with when saving seed. It all has to do with the genetic diversity needs of the plant. More about that in a minute.
To understand the importance of genetic diversity, let’s talk about the Habsburg family.
The Habsburg Family
The Habsburgs were a German-Austrian family of royals who intermarried each other across Europe to consolidate their power. The problem is, the intermarrying took its toll. Over the course of several hundred years, descendants of the original family had enormous health and infertility issues as well as what’s now referred to as the “Habsburg jaw,” or mandibular prognathism, a protruding jaw that often accompanied a sunken mid-face, a big lower lip and an unattractive long nose. In some cases, the jaw jutted so far forward, it created a massive underbite that made it hard to put teeth together to chew.
You’d think the jaw was a dominant genetic trait but you’d be wrong. It actually linked to a recessive gene. Recessive genes surface when both of an individual’s two copies of the gene are the same. So, for example, if your mom and dad are also niece and uncle (this happened to King Charles II of Spain), the recessive gene for the jaw and many other illnesses would be more likely to surface.
So why am I telling you this?
Seed Saving and Genetics
It’s easier to save some seeds than others because some types of plants require greater genetic diversity than others. Producing healthy humans requires not intermarrying for hundreds of years; otherwise, you end up with facial deformity, infertility, 50% infant mortality, a host of health issues and early death. Producing healthy plants also requires some degree of genetic diversity to produce healthy, happy plants. For plants, there’s a scale of genetic diversity needs, which I’ve outlined below. Note: I’ve re-formatted this information from San Diego Seed Company’s Urban Farm School.
“Distance Apart” refers to the distance of your crop from another that could cross-pollinate. Since peas self-pollinate within the same flower, it’s unlikely your neighbor’s pea plants will cross-pollinate with yours. With corn, however, your cornfield would ideally be 5,200 feet from another cornfield to avoid cross-pollination, since corn pollen flies through the air and can travel far.
“# of Plants Needed” relates to the number of plants you need for genetic diversity. Five pea plants will do (super easy), whereas corn requires at least 100 corn stalks to produce the level of genetic diversity needed to avoid weaker subsequent generations of crops.
If you’re a backyard gardener, you can probably get away with less than the requirements listed above. If you’re planning on sharing or selling seed, however, you’ll want to follow the guidelines to be more confident that your seed will germinate and produce good, healthy plants.
Back to My Brassicas
So how will my arugula and kale do? If you look at the chart, brassicas (broccoli is a brassica) fall on the right side, requiring high genetic diversity. Yikes! Luckily, my neighbor has a lot of land and a lot of plants (hence distance from other crops and greater genetic diversity), so the arugula has done well so far. I’ve already grown arugula from the seed (and eaten it!).
I’ll have to see how the kale goes when I plant cool-season crops starting in a month or so. Stay tuned, and happy seed saving!