I got some seeds from trades this winter, and without thinking to much about it put them in my refrigerator, which tends to be between 28 and 30 degrees cold. Did I kill my vegetable seeds? Some of them are warm climate plants.
I always thought that seeds that needed striation would be Ok in the fridge for about 6 weeks or so.
What you need to know is which plants self seed and come up the next year--(biennials)
after having spent the winter fallen down in the bed.
The only vegetable plants I know that do this is Tomatoes. But--please! I am not an expert on this.
I have not grown anything but Tomatoes, Basil and Parsley.
My used seeds are stored in a little cabinet in a pole shed. Sometimes it gets down to -30º. Seeds are always good. A big place that I buy seeds at in St.Paul stores their seed in an unheated shed. They sell seeds all over the country.
Bottom line, your seeds will be safe.
I've heard many people say they store seeds successfully for years in unheated garages.
I suspect it depends on seed size and type, and how many years they wnat to hold on. I am hoping to keep some salvia and delphinium seeds for more than one year. (And dozens of other flowers.)
I worry more about humidity, and variations in humidity and temperature. I may worry too much.
I store seeds in plastic jars that held two pounds of peanuts or peanut butter, with some silica gel dessicant. I have relative humidity indicator cards that show around 10% RH inside the jars.
I pour some silica gel into a paper coin envelope and staple it shut with two staples. This lets humidty be pulled out of the jar gradually through the paper and flap. The staples keep the finely powdered gel (imagine powdered glass) from getting into the jar and onto my fingers.
The seeds are usually double-Zip-lock-bagged inside the jars, which further slows humidity variations, as when I open jars. I dry them thorughly before sealing the Zip-locks, and humidity CAN migrate slowly right through plastic, and also through the "zip" closure.
I live in the Pacific NorthWet, with rain almost every day for months.
I let my room temperature vary as low as 50-55 F, or as high as the rare sunny day takes it while I'm at work. I found a bureau drawer that never gets direct sun.
In principle, I might dry the seeds TOO much and kill them, but I hope the double-bagging and frequent opening of the jars prevents that. I'll know better next spring how that works!
I've heard that, after preventing humidity and temperature variations, seed life is prolonged by storage in a refridgerator. Very dry seeds can be kept even longer if frozen dry and NOT subjected to freeze-thaw cycles.