Do you use Tom Clothier's Database?
I do, especially this time of year. One of the most common questions in the peak of WS season is whether to plant something "now". The question usually has "too late" or "too early" as part of the subtext. The database lists ideal temperature for germination and how long it should take to germinate at that temp. It also indicates whether a seed needs to be exposed to cold, ie cold stratification and for how long. I use the database as a thumbnail gauge for how early or late something should be planted.
As an example, I was received some hosta seeds in the mail today. I've never sown hosta, so I went to Tom Clothier and looked them up.
It said "Hosta elata, minor, montana, sieboldiana, and ventricosa , Sow at 20ÂºC (68ÂºF), if no germination in 3-4 wks, move to -4 to +4ÂºC (24-39ÂºF) for 2-4 wks, recycle".
First that tells me they aren't frost tender and don't need to be held until later. Second it tells me that a little cold strat won't hurt, and may help. In other words, it's not too late, but I don't want to wait until the temps here warm up to the mid 80s.
I use the database extensively in the late fall. I take my seeds out of alphbetical order and put them in order by sowing date, with the sowing date corresponding to typical temperatures in my region. I use tabs with ranges of half months (Dec 16-30, January 1-15, etc.) If something needs four months at 24-39 degrees, it would be sown first. Something that needs two weeks at 40 degrees would be sown later in the cold season but not last, and so on. I do this because of the volume of containers I plant. It's not realistic to think I can have everything sown by the end of January. I don't want to come across seeds at the end of the alphabet in mid May only to discover they needed two months of cold to germinate, or would have had peak germination at 50 degrees.
One thing not to do when using the database is to try to mimick the listing exactly. It was designed for greenhouse growers who want to cut to the chase instead of letting mother nature do the work for them. As a winter sower it is best used as a general guideline for determining too early or too late.
Hope this helps someone.
Here is a link that might be useful: Tom Clothier's database