Seed Saving: Beans & Peas

By Jill Henderson – Show Me Oz
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If you are planning on saving some of your own seeds this coming summer, the very best time to start is before a single seed goes in the ground. In fact, saving seed should begin with that catalog you’ve been perusing all winter. Seed catalogs are often filled to the brim with valuable information on the crops you want to grow, including germination times, growth characteristics, suggested planting dates and so on. But the best part is that many catalogs now list each vegetable’s Latin botanical name, as well. For the seed saver, those two little words written in italics and perched between parenthesis can mean the difference between seed saving success or seed saving failure.

Those of you who read my blog regularly already know that botanical names are used to identify all of the plants in our gardens. Each plant has a family name and a two-word Latin name. Together, these three little words tell exactly which plants have close family (and genetic) relationships and which ones don’t. This information is critical if you want to keep closely related plants from cross pollinating one another.

Taking the time to learn how garden plants are related is probably the most important thing you will ever do as a seed saver. I highly recommend writing the plant’s botanical name on the front of every pack of seeds you buy (or save). This will not only help you learn the names faster, but it also makes a good reference at planting time.

If you would like to learn more about botanical nomenclature, you might enjoy reading my article, Winter Seed Saving: Pumpkins and Squash or you can learn more by reading my book, The Garden Seed Saving Guide: Seed Saving for Everyone .

This week, our seed saving venture will focus on legumes: specifically beans and peas.

If you are planning on saving seeds from any kind of bean or pea in your garden this year, you will want to know that all of the beans and peas we grow in our gardens belong to the Fabaceae, or Legume, family of plants (formerly known as Leguminosae).

This is important to the seed saver because all members of the legume family have perfect, self-pollinating flowers. Each individual legume flower contains both male and female reproductive organs. In fact, the perfect, self-compatible flowers of legumes do not rely on insects or wind to move pollen from flower to flower. Rather, pollination occurs within each individual flower, often before the flower ever opens.

The fact that legumes tend to pollinate themselves before the flower opens fully his does not preclude the chance that insects will get into the flower before it opens fully or before the flower has pollinated itself and move pollen from plant to plant. In fact, some of the larger pollinators, such as bumble bees, can force their way into much larger flowers than legumes and insects, such as bean beetles, often chew on the petals of unopened flowers. Legumes have a 35% chance of being cross pollinated by insects. Admittedly, it is a slim possibility, but a possibility none-the-less. As a seed saver, you want to reduce the odds in your favor.

You can help yourself greatly by learning the genus and species name of each legume you wish to grow. The more closely related they are (i.e., the more names they share in common), the higher the likelihood that cross pollination can occur. To help illustrate this point, here are just a few members of the very large legume family:

Pole Beans (Phaseolus vulgaris)
Bush Beans (Phaseolus vulgaris)
Black Beans (Phaseolus vulgaris)
Garbanzo or Chick Pea (Cicer arietinum)
Hyacinth Bean (Dolichos lablab)
Soybean (Glycine max)
Copwpea (Vigna unguiculata)
Mung bean (Vigna radiate)
Garden peas (Pisum sativum)
Edible-podded peas (Pisum sativum var. sativum)

Notice the first and last Latin name of each of these beans and peas. Some, like the pole beans, bush beans and dry beans share the same exact family, genus (Phaseolus) and species (vulgaris). This indicates that all common beans share an incredible amount of genetic similarities and are prone to cross pollination. The same is true of cowpeas and mung beans: these plants share a common genus (Vigna), but not a common species name. This should indicate that while these two plants are very closely related, they are not close enough to cross pollinate one another.

In short, those plants that share the same genus have the potential to cross pollinate – but probably won’t. But those that share the same genus and species, probably will. Those that don’t share either the genus or species will never cross pollinate one another. So, if you are planning on planting several kinds of legume in the same garden, you will definitely want to know which ones can cross pollinate, which ones can’t and which ones might. Then all you have to do is find a way to ensure they don’t.

As we now know, all legume family members have perfect self pollinating flowers. This is good news for the seed saver, because it means that nature is going to do most of the work for you. Since these flowers generally pollinate themselves before they ever open, all you need to do to prevent cross pollination is to practice a simple isolation technique.

You can elect to provide a little extra space in between different varieties or stagger planting times so that different varieties flower at different times. Leaving 3’-4’ between groups is often sufficient enough distance to prevent cross pollination. If you are growing a very rare bean, you might add a little more space just to be sure. Planting another crop in between is also a good way to create distance between related species.

Another benefit of saving legumes is that they do not suffer from the dreaded “inbreeding depression” – a sort of genetic bottleneck that occurs when too few seeds are saved from too few plants.

Inbreeding depression causes all kinds of problems that become increasingly evident as each generation of seeds is grown out. Problems such as low germination rate, loss of disease or pest resistance, loss of vigor, flavor, and more. While not strictly necessary with legumes, it is good seedsmanship to save seeds from at least three or four different plants to help retain the natural genetic diversity that exists within each variety.

By planning now to save seed later, you can grow more varieties with the assurance that each and every one will retain their own unique characteristics for generations to come.

Happy Gardening!

This article was excerpted in part from
The Garden Seed Saving Guide:
Seed Saving for Everyone
Whether you’re a weekend gardener, homesteader, or serious survivalist, saving seeds is a money-saving skill that every green-thumb should to have. An excellent resource for beginners and experienced gardeners alike, The Garden Seed Saving Guide takes you step-by-step through every aspect of saving seeds. If you want to save money, become more self-sufficient and avoid genetically modified food crops, The Garden Seed Saving Guide is for you.