It is well known that some seeds require stratification. Perennial sweet peas for one. I wonder if for the annual varieties it might not be absolutely necessary, but might be helpful to some degree. Have you ever experimented or tried it?
I have never grown perennial sweet peas and this year, for the first time or should I say last year, I sowed my sweet peas using my favoured chitting method in early September and grew them on as biennials. The pic below is the result as of 4th February.
(ps
As things stand I think I will be going back to spring sowing next year I don't like how 'leggy these plants have become) This is the nearest experience I have had to your question and as it happened the temperatures in September were relatively mild as I recall, so they did not undergo particularly cold temperatures like you would get from true COLD stratification. In fact, they had chitted by the 12th Sept when I covered them with compost.
In terms of stratifying, the 2nd photo are a number of seed varieties I am currently stratifying. The chart is a section of my sowing plan, where the code C2 or C4 means cold stratification for 2 or 4 weeks and the date in the Off column is the date I move them from the cold into warmer conditions.
To date; none of my stratified seeds have germinated yet!
Based on how 'global warming' is affecting our seasons, I am not sure short of placing them in the fridge if we will ever get the full effect of 'coldframe stratification'again!
On that note; I don't think t'other half would take kindly to me using our fridge for germinating seeds. I know I got a few choice comments when I commandeered the Microwave to sterilise my seed compost. Luck had it for me when the turntable on the microwave stopped turning, and I had an excuse to replace it with a new one, and I got the old one in my greenhouse! As you can see in pic 4
