Seed Preservation (P)
Storing seed will ensure that in a long-term disaster you will have access to needed nutrition and energy for more physical exertion and mental clarity. Those who have started their survival gardens have learned from mistakes along the way. Through these mistakes, gardeners have stumbled upon wisdom and improved their skills. These experienced gardeners have taken certain factors into consideration before the seeds are planted, and through experience found which varieties are easier to grow.
Types of Seeds
From the point of view of their preservation, seeds are usually distinguished in two groups; orthodox or recalcitrant. Orthodox seeds can be desiccated down to moisture contents of 4-7% and even ultra-desiccated down to contents of 1-3%. This way the moisture factor can be used without restrictions in helping to achieve added longevity. Recalcitrant seeds do not tolerate desiccation well. This makes added procedures necessary. Desiccation, by the way, is the actual procedure of drying seeds.
Low moisture, low temperature, low ethylene concentration and low oxygen concentrations are the most relevant factors to keep in mind when thinking about arranging efficient long term seed preservation.
Low moisture and low temperature concentrations are traditionally considered factors. Over the past few decades, however, low temperature concentrations have received much more attention, while an efficient control of low moisture has been largely neglected. In order to guarantee efficient long term preservation of orthodox seeds, you must control seed moisture content.
Two major points should be taken into account:
Your container of choice should be perfectly tight, preventing water vapor intake. If the container is not perfectly vapor tight, the seeds will balance with external air humidity. Any potential benefit of low temperature concentration will be offset by an increase in seed moisture. Keep in mind that relative humidity inside any uncontrolled cold room is usually very high. Unfortunately, the use of inadequate containers has been commonplace in seed gene banks. Some experts point to this factor in contributing to Americans’ increasing obesity. Namely, since the gene banks often rob their seeds of valuable nutrients, the subsequent fruits, vegetables and plants grown suffer from nutrient deficiency. As a result, eating two, three or four tomatoes, may leave the human body desiring that ominous extra bite. The reason is that even though a person has eaten a seemingly large amount of food, their body is still craving the nutrients in which the original seed of the plant was deficient. No matter how healthy our tomato looks and how delicious it tastes, it is likely lacking the nutrients our bodies crave.
Choice of Containers
For many years it has been widely accepted that containers which are appropriate for cold drinks or to store chips for a few months, are also appropriate for long term seed storage. This is simply not true. You should question any source which makes this sort of claim. The results of a recent survey on 40 different container types – some of which are widely used in gene banks – showed that 36 of them allowed moisture to get inside in less than three years. In order to properly preserve your seed you will need a set-up which will allow you to store your seed for very long periods of time, without any moisture getting in. If 90% of the containers used by gene banks allow moisture to get in, it is no shock that GMO seeding is getting such a bad rap around the world.
All plastic containers allow moisture inside. The water molecule is small enough to get through the pores of the polymers used to make the plastics and in the medium and long term, that fact is unavoidable. Polyvinyl bags are especially permeable to humidity. An additional reason for the failure of plastic containers with a lid is because the two pieces are usually made of different materials. They expand or contract in a different ways when temperatures change. This creates fissures which allow humidity to get inside the container. This problem appears not only in plastic containers, but also in most glass containers with twist-off or screw lid. Even plasticized twist-off type jelly jars often show oxidation stains after some time has passed.
Aluminum foil bags also merit mention because of they are still used in gene banks. It has been a long time since bi-laminated bags (coated with plastic only on one side) were rejected on the basis of their inefficiency. Tri-laminated bags (coated on both sides) are widely accepted, however.
The most commonly used procedure to date, has consisted of drying seeds with different procedures until they reach a moisture content of approximately 5-7%. Afterwards, the seeds are placed in containers whose vapor tightness is most often untested and the success is mainly trusted to low temperatures. Ultra drying has been used by no more than 50 gene banks out of more than 1,500 existing in the world. Extensive studies prove that ultra-drying orthodox seeds proves of comparatively lesser importance than the temperature used for storage of ultra-dried seeds themselves.
It should be noted that moisture content of 4-5% may be enough for the efficient conservation of some orthodox seeds, such as those of many legumes (beans). Generally speaking, ultra-drying can be viewed as very efficient with regards to orthodox seeds.
Freeze drying has been successfully used to obtain ultra-dry levels of moisture. This procedure consists of freezing the seed water and sublimating the ice afterwards. Freeze dried seeds do not suffer any decrease in their viability due to the process. Many folks will simply tell you that keeping your seeds in a cool dry location is best. Some use the fridge or the freezer, while a cool closet will be fine for most. If you do store them in the freezer, you need to let the container come to room temperature before opening.