Beans, Phaseolus vulgaris
The common bean is perhaps the ultimate seed to seed crop. It is easy to grow, easy to keep the bean variety from cross pollinating with other varieties, and easy to save and store the seed. If you don’t do anything else this year, grow, eat and save some bean seeds.
As a member of the legume family, the common bean will fix nitrogen into your soil, even as it grows edible pods and develops storable and edible seeds. As a food source, beans have much to offer. They are high in protein, a good source of carbohydrates and fiber, and they have a low glycemic index.
The sheer varietal choice makes beans exciting in of themselves, plus there is a great Appalachian tradition of beans to explore. When it comes to beans, there are a lot of different descriptions that go along with the beans!
A brief bean glossary of some common bean terms:
Bush beans vs pole beans
Added to all this choice is the distinction between bush and pole beans. Bush beans have a more compact habit, although random vines can get excited and wander off. Bush beans also tend to mature at the same time, with one concentrated fruit set. This often makes bush beans good candidates for dried beans, where a single harvest is best for processing. Pole beans require some form of support, whether it is a trellis, a fence or a corn stalk. They can vary in height from 6ft to 20ft+ depending on variety. Pole beans will mature over time as they continue to grow and set flowers and pods. Pole beans are preferred for green beans to stagger the fresh harvest over time.
Beans are a frost sensitive annual, but they can tolerate slighter cooler soil. Many people will risk an early planting of beans towards the end of April, sowing a quick maturing bush bean such as Provider (50 days to harvest) to get their first summer green beans as soon as possible. Bush beans are best sown in successions about two weeks apart to get a continual harvest throughout the season. Remember that if you want dry beans, or beans for seed saving, you’ll need the leave the plant in the ground for longer than you would for a green bean harvest.
Pole beans will keep on growing and producing over a longer harvest window and so tend to attract more pest problems. Mexican bean beetles are a common foe and will leave your leaves looking like they’re made from lace as the plants are rapidly defoliated. They can be squashed by hand in their larval stage, but constant vigilance is the key as populations can quickly run out of control.
Saving bean seeds
Bean flowers are perfect and self-fertile, meaning they can pollinate themselves. While bees will visit bean flowers, cross pollination does not happen very easily. Different bean varieties only need to be separated by 10-20ft to avoid cross-pollination. That means making sure your Cherokee Trail of Tears, or your Kentucky Wonder, stays true-to-type is very achievable even in a small garden.
The seeds are ready to harvest when the pods are fully dry and brittle. It is best if this can happen on the vine. However, if heavy rains threaten a mostly dry seed set, pull the vines or pods and continue to dry under cover. Molding and re-hydration of the pod can negatively affect your seed crop.
Small amounts of pods can be hand shelled for seed saving. Make sure you label your different seed varieties. Larger quantities can be threshed (crushed to separate the pod from the seed) and then winnowed (using wind to blow the lighter pod debris or chaff from the heavier seed). At Sow True Seed we use a box fan to do our winnowing and it is very effective.
Storing seeds requires a cool, dark and dry environment. Bean seeds can be assessed for moisture pretty easily. Place one seed on a solid surface and hit it with a hammer. If it shatters it is dry enough, if it smooshes it is not dry enough. Freezing is an effective tool to prevent bean weevils from destroying your seed crop, but even without freezing, bean seeds will store for 3-6 years.