| Ditto on Fusion's comments. Before you begin to discuss storage, the seeds must be properly dried. It's impractical as a home gardener to measure actual moisture content; but there are several methods of drying which work reliably. Some use dehydrators (at low temps only!) to dry seed, while others weigh the seed, measure a fixed amount of desiccant, and place both in a sealed container. In my Northern location, the air indoors becomes very dry in early Winter, so I use that to my advantage. I allow the seeds to dry on stacked trays, stirring them occasionally for the first month; a fan on low speed is helpful during this time (I use a ceiling fan). When the thermometer stays below freezing & 1/4" sparks begin flying from my sweater, the seed is dry enough. Unscientific, I know... but the beans I store at room temperature have good germination for 4-5 years, so I know it works. The rule of thumb for drying beans is that if the seed shatters cleanly when struck with a hammer, it's dry enough to store. Once the beans are dry, I store them in ziplock freezer bags, since they are more air-tight. For the bulk of my beans, the bags are then stored in boxes to keep out light. If the room where they are kept is air conditioned in Summer, this will significantly extend their life. Avoid warm locations, such as near heating vents, or in cupboards near the ceiling, where heat rises. In Winter, I close off the vent where I store my seeds, and allow the room to cool. A cool basement can also be a good storage location... but to protect against the possibility of moisture intrusion, the seeds (with or without bags) should be placed in air-tight containers, such as canning jars with rubber seals. For frozen storage, sealed jars are best. Ziplocks alone run the risk of freeze-drying the seed (especially for long-term storage) should they leak. I only keep back-up samples in the freezer, to minimize the space used. For frozen/refrigerated seed, be sure to allow the container - still closed - to warm to room temperature before opening. If opened too soon, moisture can condense on the cold seeds, leading to spoilage. For larger amounts of seed, dividing them between several ziplocks in the same jar allows you to remove just the seed you need, without warming the entire quantity. Frequent warming & cooling is detrimental to long-term storage. The seed life is determined primarily by the moisture content of the seed, the storage temperature, and the species. The numbers given by Fusion are a good rule of thumb for beans in general. SSE uses refrigerated storage (at about 40 F. degrees) with controlled humidity, and most seeds maintain good germination for 10 years. The USDA uses -20 C. degrees (-4 F.) for long-term storage; a stand-alone home freezer is usually very close to this, at about -17 C. (0 F.). The icebox attached to a refrigerator will not be this cold, and the temperature will fluctuate often; so while it is OK for medium storage, a stand-alone (if available) should be used for the long-term. Another factor that influences seed storage is the health of the seed. The seed should be sorted, and fat, healthy seed selected for storage. Seed that is diseased, shrunken, or has been exposed to frost or excessive moisture, should not be used for long-term storage if it can be avoided. You can sometimes increase the size of bean seed - and its viability - by giving the plants wider spacing than you would normally. I use 6" (about 15 cm) between plants for bush beans, twice that for most pole beans, and 2-3 feet for limas. As Fusion mentioned, there will be variations in storage life, even between beans dried & stored under the same conditions. When a decrease in germination is noticed for a variety, it should be regrown for seed as soon as possible. The remaining viable seed could deteriorate completely within several years. If you don't plant every year & choose not to do germination testing, keep a sample of each variety in the freezer as insurance. |
