Have you ever wondered how we keep our Seed Library organized and up-to-date here at Seeds of Diversity? With the large volume of seeds that we receive, we have to make sure they all end up in the right places.
When a new package of seeds comes to us, our first step is to determine whether or not we already have that variety in storage. The Seed Library has two types of storage: permanent (dehydrated and stored in a deep-freezer) and temporary (stored at room temperature for easy access). If we already have a significant amount of a variety in permanent storage, we put the new seed into temporary storage. If we don’t, the new seed is divided into two, and put in both temporary and permanent storage.
All new seeds are weighed, and their gram weight amounts are entered into our online database. We also enter the date of harvest, date received, variety name, cultivar number, and the source of the seed. The seeds either go into envelopes, small jars, or large jars, depending on how many there are. Envelopes and jars that are destined for temporary locations are carefully catalogued, labeled, given a searchable code, and then shelved, until they are used in one of our grow-outs, provided to seed savers for multiplication, or offered to new partner community seed banks.
The next step is to test the quality and viability of the seed. If we have enough seed, we do germination tests before they go into storage. For most seeds, this involves counting out 25 or 50 seeds, rolling them up in moist paper towels, and placing them in a cool, dry place for up to 10 days. We then observe how many have sprouted to get an idea of the germination rate of that sample. This germination rate is very important, particularly for growers who may use the seed to grow commercial crops.
A general rule for regeneration (re-growing fresh seeds from older seeds) is 85% of the original germination rate. This means testing when a seed arrives to us, and then repeating that test from time to time. When the germination rate falls to 85% of the first result, the seeds should be regrown to provide a fresh sample. E.g. if a sample had an initial 95% germination rate, we would regrow when its germination rate reached 85% x 95% = 80.75%.
The other half of the seeds go into permanent storage, where they are stored in air-tight glass jars. However, since they will be stored for longer before they are grown out, these seeds must be dehydrated in order to maximize their long-term viability. Dehydration involves removing as much moisture as possible from the seeds before sealing them in storage containers. We do this by laying seeds in silica gel, within a sealed compartment, for one week. Silica gel effectively absorbs all excess moisture in the seeds and the air around them. It can be “recharged” by heating it, so that we can use it again for the next batch of seeds.
It is very important to remove moisture from the seeds before they are stored for a long period of time. Moisture can cause the seeds to become mouldy or possibly even germinate. Once the seeds are dehydrated, they are shipped to our Seed Library partner, Everdale Farm, where they are frozen for future use. This is another reason that drying the seeds is essential: moisture in the seeds can freeze into ice crystals that damage the seed.
Adapted from this article written by Brittney Glass, an intern at Seeds of Diversity Canada in 2015.