Re: Re: HYB: germination - "no" chill

Looking back over the archived climate data for the period between planting and getting green shoots, there were a total of 14 nights with temps between 33 and 40 degrees. Most of those were in the first two weeks of the 6 week period. 4 were in the second two weeks and 3 in the final two weeks. The total rainfall for the period was 5 inches, with the bulk of the days being measured less than .05", and 14 days with .20" to .66". We dipped from above 40 to below 31 degrees 8 times during those six weeks. The interesting change was the week before sprouts started appearing. In those 7 days there was no rain, and nighttime temps were steady in the range of 59-64 degrees. The 2 weeks prior to that had temps hovering at 43 +/- 2 degrees with two nights at 54, and two at 38. Note that the temps represent lows, not averages for the nights...that is to say on a 40 degree night it may have only reached 40 for an hour or so. And while moisture was constant, I would not call it copious. I had always heard you needed vast quantities of water to leach out inhibitors. I believe that may be why I had such poor germination back in the mid 90s...I watered daily only to have few sprouts and many empty seed husks.
John, from what was posted here previously (assuming I remember right), the temperature required for removing germination inhibitors is below 40oF. Once temperatures drop (much?) below freezing, the process stops. So seeds could stay frozen for a long time and still need the chilling hours.
Do you know how many days with at least night temperatures below 40oF your spring planted seeds experienced before germinating? 

---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE IRIS
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index