I am wondering if there are seeds that are harmed by cold stratification? If not ...why not fridge treat every seed?
Having gardened for ~ 30 years, it is often a pain to try to remember or look up every seed to determine if it should be cold stratified for 1 - 10 weeks in the fridge. Especially when you are planting > 100 seed types as I am this year starting in the basement any time now. Most of what I am planting this year are all new to me so I am not familiar with all the particulars of germination - scarify or not. Stratify or not. Smoke treat or night. Do I need to buy some more hydrochloric acid (hard to come by) or not. Et cetera.
Since essentially ALL temperate seeds fall in the Fall and are cold stratified by Nature - for those of us who collect or purchase seeds in the Fall - should we just stratify everything ...? But not tropicals, obviously.
No, seeds that don't actually require stratification are not harmed by it. That's true for stratifying where the seed is prevented from actually freezing, such as in a fridge. If you are stratifying outdoors in a cold climate, where the seeds might actually freeze, then any plant that you can expect to be hardy there, should be fine with this treatment (and many others will be as well, e.g. many annuals).
I start a lot of plants from seed and there is no information available on many of them. Those I know nothing about (i.e. unfamiliar genera where there is no "usual" treatment to go by), I usually start out at room temperature. If, after 2-3 weeks there is no germination, then I put the pots in the cold room for a few weeks of stratification, which usually does the trick. There's no reason why you couldn't leave out the first step, I suppose.
As a general rule, germination of pea family plant seeds is hugely sped up by scarification... it speeds up germination in some others as well. If you have seeds that you think you need to treat with HCl, you'll get the same result, more simply, just from scarifying.
Smoke treatment is only required for particular genera, and unless you are growing some more advanced subjects(?), you may not need to consider it at all.
Seeds with long dormancy, such as Iris, I sow in plastic shoe boxes filled with potting soil and left outside covered (or in unheated garage or shed). They will sprout in early spring when temp reaches 55-70 degrees.
1] Sowed November 2011, Photo taken April 1,2012
2] Planted in open coldframe, May 30, 2012
3] The result. Bloomed June 2013
The fridge can be used but take longer to work. The secret to success for many seeds is flunctuating temps with moisture--- such as Nature provides---to break the dormancy of seeds.
Longer than what? The reason I ask is because you control the length of the cold period in the fridge or coldroom - I usually go for 6 weeks, then pull the pots out and see if germination occurs at room temperature (this provides the fluctuating temperatures); if there's no germination in a couple weeks, they're returned to the cold for another go, and pulled out for another warm period again later. This gives me seedlings much quicker, that can put on lot more growth prior to planting out, than if I "winter sow" and use the natural temperature cycle.
Yes the sower controls the lenght of the cold period, but not everyone has space for a lot of seeds in their fridge. I for one don't and can't be bothered taking seeds in and out of the fridge even if I had the space. Also, I am not in any hurry for my seeds to sprout before April for lack of indoor growing room, which is taken up by daylily seedlings.
Depending on the seed variety, 3 weeks usually works
Some day I am going to have a 'frig dedicated to gardening, and maybe a cold room too.
To save space, now, I am sprouting seeds either on moist paper towel or in moist vermiculite.
These are in small plastic containers which I get at the Dollarama. I can sprout quite a few by chilling many small boxes in the unheated garage.
The beauty of the old milk jug WS is that there is no rush for transplantsing as the plants will keep
in the milk jugs.
Someday I will also have a fridge for seeds but have to wait until i install electricity in my new shed. Wal-Mart has the size that would fit nicely.
Speaking of containers, I have had a a taste for Taco Johns salads lately. They have the area where you can get the sauces to place them in tiny containers with covers. I have began to save them for they are perfect for germinating seeds, instead on baggies. And they stack nicely.
Thanks for all the responses. I had my settings wrong and was not flagged WRT the responses. :-((
Yah on wishing for a spare frig. hehe
WRT the paw paws - that makes absolutely no sense. heh I live in Zone 5B The paw paws fall off in the fall. Lay on the ground and freeze! Then in spring - some of them pop up. Like many, many other seeds in temperate areas.
There is some great info at the Hudson site including links to some germination research by Deno - see
This year I am planting seeds from Africa and Australia that require smoke treatment. Two methods that can be used are to use Liquid smoke like Colgins or Wrights. Another is to place 2 - 4 inches of leaves on seedings, light them on fire and then pour water thru the ashes. Heh Or you can buy the expensive smoke discs.
I would like to try GIBBERELLIC ACID-3 (GA-3), but it is also a freaking pain. No one size fits all. :( So much for this, so much for that.
Finally, WRT scarifying - I always scarify any seed that appears to need it. I have ran many, many tests and experiments and scarifying can improve the speed of germination by as much as 90 %.