vegetable seed viability greatly underestimated

I have issues with throwing away seeds that I bought then didn't plant for some reason. Having recently retired I can now garden all I want. I have a bunch of seed packets I've been carting around with me from refrigerator to refrigerator as I moved over the past several decades. I'm finding that seeds last a WHOLE LOT LONGER than all the "expert" tables I've seen.

Last year I germinated Henry Field's sweet corn seed "Cotton Candy Lot C packed for 1996" in wet paper towels in a lidded plastic container. Of 250 seeds, 248 germinated; that's 99% germination in 18 year old seed. This year I put 112 seeds of Petite Pois Precoville from Burpee, (packed for 1990 so it's 25 years old) in wet paper towels in a washed plastic bakery tray on March 20. Today (March 30) I transferred the germinated peas into cell packs and peat moss. Of 112 peas, 104 germinated, about 93% germination from 25 year old seed. Possibly some of the 8 failures might have also germinated except by 10 days on wet paper towels I start getting mold.

These seeds were kept in their own paper packets, bundled with a bunch of other packets in a large plastic bag, in a box in the fridge (not the freezer). I didn't do anything like squeeze out all the air and seal it or anything. I've moved 3 times, so 3 different refrigerators too. I've seen a lot of recommendations to throw out "old" seed and buy new; I wouldn't throw anything out until I tried germinating it.

According to the table on many internet sites including university websites, sweet corn viability is 1-2 years, and pea viability is 3 years.

I agree that everyone's proverbial "mileage" can vary significantly. Most of my holdover seeds have remained viable for several years. Assuming I have the time and ability to test viability, it is definitely worth giving them the old college try before tossing them out!

Firm believer in fridge storage too and am still using many seeds that are over a decade old. Can't top your 1996 seeds but have just germinated tomato seeds from a packet dated 2002. Can't bring myself to toss seeds. But then I have trouble tossing anything away. :)

Dave

I like to put some silica gel in paper envelopes and store them with seeds, sealing the combination inside plastic Ziplocs and plastic jars.

Seeds are said to stay viable much longer if kept around 15-30% relative humidity instead of around 50% RH.


"Seed life span approximately doubles for every 10% reduction in seed eRH."
Millennium Seed Bank Project, Kew Royal Botanic gardens
www.kew.org/msbp


http://www.kew.org/sites/default/files/4_ppcont_014345_Post-harvest%20handling%20of%20seed%20collections.pdf

Oooh!

I have some old seeds from a few years ago to try...

Cross your fingers for me!

Thanks for the Kew article. Now I'm curious what the relative humidity is in the average fridge. I suspect it's pretty low in general, as I habitually dry mushrooms by putting them in a paper bag and leaving them in the fridge to dehydrate. I haven't done anything like silica gel to maintain dryness of my seed packets, but if it makes them last longer I'll have to find some. Actually for the first few years I just stuck the packets in a small cardboard box in the back of a shelf; later I started stuffing them into large plastic bags first because I was worried they would completely dessicate and die--go figure. So far, I've only tried growing the corn and peas; later this spring I hope to try some melon seeds. And this does give me incentive to try saving some of my own seed as well. I'm with Dave; I have problems throwing stuff away. Wastage!

Last year,though, a friend gave me half a packet of year-old bean seeds (no idea how they were stored) and not a one germinated for me. So not everything may store well.

I think that modern "frost-free" refrigerators probably tend to be dryish after the door has been closed for an hour or two, but don;t they shoot up to 100% RH every time you open the door, let room air in, and then close the door so it chills?

Certainly frost-free freezers will dehydrate things if you leave the door closed long enough. But every time humidity condenses on something, its "humidity" isd more than 100%, it is covered with frost.

That's why I stopped storing seeds in the fridge: every time I wnated to open the jar, I had to wait hours for it to warm up before I could open it.

P.S. The vegetable "crisper drawer" is the MOST humid part of a fridge, not the driest.

I forget whether I said: you can buy 1-2 pounds of silica gel for $7-8 at craft stores. The flower-drying isle.

I shovel a tablespoon or two into paper coin envelopes and staple them closed. The humidity passes right through paper.

You can re-charge the silica gel in an oven at 250F for several hours (no hotter or you damage the silica!)

Also, I agree with the idea that many seeds survive LOTS longer than anyone expects, sometimes despite the storage conditions. Other times, they don't.

I haven't gotten any condensation when I open my seed storage, but the packets are in plastic zipper bags rather than glass or jars of any type, maybe that's why.

There's a new hobby store opening near here this month and they are big enough that I'm sure they have silica gel (can't hurt). These seeds have been moved around a lot, through 3 different houses/refrigerators. If they last many more years I'll be bequeathing them to my nephews in my will. There's something in there from 1988 that I plan to dig out and try, just to see, but I think that's the oldest seeds I have.

Didn't plan a seed longevity experiment, it just happened. I wonder if (not counting the seeds from archeological digs) anybody has done any deliberate experiments like this. One researcher would have to start by saving the seeds but depend on the next generation to complete the experiment!!!

There are some seed banks that are very serious about maintaining their store of viable seeds. I'm pretty sure they do controlled tests on how to extend the longevity of seeds as part of their research.

I've been hunting for the source of that seed longevity table that's been copied and posted on many websites. I finally tracked it to the USDA National Seed Laboratory (http://www.nsl.fs.fed.us/) by way of a Colorado State University and ag extension service publication (http://www.ext.colostate.edu/pubs/garden/07221.pdf). The National Seed Laboratory does germination percentage tests for a fee.

Here's the interesting part: that is apparently not a table of how long you can expect seeds to remain viable on average. It's looks like it's a table of how long seed MUST remain viable and how high the germination percent MUST be to meet Colorado Seed Law minimum requirements to sell vegetable seed. There's been discussion on this site that the seed packet you buy marked Packed for Year Dot may have actually been grown several years before that--it looks like there are regulations about how many years that can be depending on the specific vegetable. The Colorado State pamphlet referenced above states that seed dryness and temps below 40 degrees are the factors that influence longevity, that the atmosphere whether O2, CO2, or N2 makes no difference, and that seed "storage may be extended to 10 or more years under proper conditions". There is also a disclaimer that this applies to vegetable seed only, there are no such requirements for flower seed, and the "only assurance of quality is the reputation of the seed company".

It appears that table may have been misunderstood and the misunderstanding duplicated throughout many internet garden related sites. Of course, IT COULD JUST BE ME.

Great point, Sheepwrecked!

Everyone in the world seems inclined to grab onto a few words and ignore the rest of the warnings.

I always wondered why almost every "Internet seed viability table" listed most things MUCH shorter than most people's actual experience indicated.

I worry about humidity, then someone tells me that they planted corn that their grandfather abandoned in a paper bag in a musty, humid shed decades ago, and they sprouted (some of them).

RE: "They never read the manual":

When we wrote a new User Manual for a product our company made, one co-worker wanted to put a coupon on page 100, saying "If you find this coupon, return to XXXX for a $10 reward!" He claimed no one would redeem one because no one ever read the manual.

So I started asking about our Manual when I went out on service calls. The usual reply was "Sure, we HAVE the Manual!" Then they would go to some remote location and pull out a dusty, cob-web-covered manual to show me they still HAD it.

I just sowed some sweet peppers seeds from 2011 and they germinated and the one from 2014 did not . I could not believe it and the plants and growing very healthy .I also sowed some Big Boy tomato seeds from 2012 and had good results too. Most of my seeds are stored in a zip lock bag and put them in the Crisper of the refridgerator

Agreed wholeheartedly. I have saved them for years in my garage fridge and almost always get results.

By the way, the crisper drawer has the HIGHEST humidity of any part of the fridge. It keeps vegetables crisp by keeping them from drying out.

The one advantage it has for seed storage is that it doesn't get as much condensation every time you open the door.

Clearly I worry too much about humidity for long-term storage. But Royal Kew gardens, and some other sites, do say that your viable time roughly doubles for every 10% less Relative Humidity you can keep constant.

Post-harvest handling for seed collection:

http://www.kew.org/sites/default/files/04-Post%20harvest%20handling%20web_0.pdf

"Seed life span approximately doubles for every 10% reduction in seed eRH."
("eRH" is equilibrium Relative Humidity.)