Tuesday, 6 October 2015

08:19 – We got a couple dozen biology kits and science kits built yesterday, so our inventory status is back up to a reasonable level for this time of year other than for forensic science kits, which we’ll work on today and tomorrow. I also issued two orders yesterday for more open-pollinated seeds, which is the last of what we need for the first batch of two dozen heirloom seed kits. Dehydration and testing of those begins tomorrow.

I’ve been reading a scholarly tome on seed saving, and the numbers are pretty interesting. The viable shelf-life of seeds varies significantly by species, but even more important than species are the moisture level and storage temperature. Once you get the moisture level below about 15%, each additional 1% reduction in moisture typically extends shelf life by a year or two, down to the optimum at about 7% or 8% moisture. Below that, seeds tend to “harden” and have reduced germination rates because water is unable to penetrate the seed to allow germination if the seed is planted normally. But such hardened seeds can be revivified if you allow them to rehydrate over the course of several days to a couple of weeks in a high humidity atmosphere.

But storage temperature is even more important to shelf life. Taking 70 degrees Fahrenheit as a baseline, each 10F reduction in storage temperature on average doubles the viable shelf life. That means that keeping seeds in the refrigerator at 40F extends their shelf life on average by a factor of eight. Freezing them extends it even more. On the seven different species the author of the book tested, the least stable seed type retained 95% of its initial germination rate after 11 years frozen and the most stable was calculated mathematically to retain 95% of its initial germination rate for more than 300 years. That’s very good news indeed.

While we were watching TV last night, Barbara asked me if I’d thought about long-term storage of dog food. She said she understood that Colin could eat what we eat, but wanted to know if there was any way to repackage his dry food for long term storage. Unfortunately (or fortunately from Colin’s point of view), there isn’t. Dry dog food is in fact rather moist, and it contains a lot of oils and fats. We could stick it in the dehydrator to get it down to a moisture level suitable for long-term storage and then pack it in Mylar bags with oxygen absorbers, but Colin wouldn’t want to eat it after that treatment. Actually, the best way to store dry dog food is in its original bag, where it has a shelf life of at least a year and probably two. So, as Barbara said, if things get really bad Colin is going to end up eating what we eat. Colin isn’t even slightly unhappy about that prospect.