Beans are legumes. Legumes are plants that produce seed pods, which break into two halves, spilling the seed onto the ground below. Beans are a beneficial addition to your diet as they provide a good source of protein, vitamins and minerals. Beans are grown throughout the world, and are a staple for most home growers.
Planting and Germination
Bean seeds will not germinate in temperatures below 50 degrees F or above 85 degrees F. The exception to this rule is broad bean varieties, such as aqua dulce, and Sutton dwarf, which can be planted in late winter for a very early crop the following spring. Plant bean seeds at a depth of 1 to 1 1/2 inches. For an earlier crop, start trays of seeds indoors. Once seeds have germinated, they must not be exposed to even mild frosts, as the seedlings will most likely die.
Seed Saving and Storage
Broad beans are challenging to save seed from for the home gardener, as they cross-pollinate with different varieties exceptionally easily. To save seed from broad beans, isolate the crop from any other broad bean variety within a 1/2-mile radius, which is usually impractical for non-commercial growers. If you save and plant cross-pollinated seed, the result may be an unstable hybrid, with poor or no fruit yield, poor disease resistance and inferior flavor. All other bean types are easily saved, as they do not readily cross-pollinate. Leave pods on the plants until they're thoroughly dried, with a tough, paper-like texture. Remove the beans from the pods and leave them for up to two weeks to dry fully. Store bean seeds in a cool, dry place to avoid damage and rot. The testa (skin of the seed) should not be split or cracked, otherwise the seed will not be viable and will not germinate.
Bean seeds have a tough, protective layer known as the testa to provide protection to the delicate internal structure of the seed. The testa softens, and splits during germination. The scar is the site where the seed was formerly attached to the pod. The scar is located at the indented part of the seed. Just below the scar is a small hole called the micropyle. This tiny hole allows water to pass into the seed during germination, and provides an exit point for the developing root.
The internal structure of a bean seed includes two cotyledons, which provide nutrients to the growing plant. Nestled between the two cotyledons is the embryo which is comprised of the radicle (primary root) and the plumule (first leaves and growing tip). The radicle pushes out through the micropyle to anchor into the soil, after which the plumule splits apart the testa and grows toward the sunlight, taking its nutrients from the cotyledons until the roots are able to provide the required nutrients.
Bean seeds are particularly prone to attack from rodents, such as mice. Both dried and developing seeds provide these small creatures with valuable protein and nutrients. Mice will eagerly dig up your carefully planted seed, and can devour a large crop overnight. You can cover seeded areas, but be aware that mice can squeeze through a tiny hole, and so it can be difficult to rodent-proof an enclosure. Another option is to liberally sprinkle ash from organic matter over the planted area. Ash contains sulfur, which mice will not cross. Therefore, they will be unable to reach your seeds.