Thank you for your comment. Perhaps you are right, this hadn’t come to my mind. The first year I tried the experiment there were no grey spots and the temperature was slightly higher. The problem however was that the buds developed further and they were thus more ‘open’ at the end of the experiment. If it would solve the problem, that would be worth considering of course. But I decreased the temperature further the last years just to avoid them opening further. The end goal is a cut flower of course and florists want them as closed as possible, although they surely want them to open of course. There have been some experiments with storage at sub zero temperatures even and they claimed to be successful. I do wonder however why then my first box would have been good, they were all stored at the same temperature, the only difference is the duration. But you are probably right, I should try it as well. I guess I can place a box in another cold storage at a higher temperature.

Thank you for your comment. I didn’t know cryoprotectants existed, I might have a look at that in the future, but fogging them seems like an extra task and is perhaps not very easy to do. The research station has stopped work on this, project money ran out. I’ve filled two boxes this year, but I’ll only know the results in August or September obviously. I couldn’t really fill more of them as there was lots of botrytis in the field this year due to the bad weather this Spring. If peonies go into the boxes with botrytis, you cannot expect them to come out of it healthy… With only two boxes, not too many tests can be done, so I’ve opted for ‘slowly’ decreasing oxygen instead of fast as that could be one of the causes of the ‘grey flecks’. And I also won’t go as deep, I want to keep it around or slightly above 5%. I’ve mostly used Coral Charm this time as this variety was resistant to bud botrytis (most botrytis in the field occurred at the bottom of the buds) and because it is a variety which can be cut tight and still opens fine (and much slower than its sister Coral Sunset). I’ll post a article about it somewhere in the Autumn, I hope I can report some good results this time.-

@bobjohnson Yes, this year’s seeds. But they were mature halfway August, earlier than yours. Then soaked for two days and then all the different treatments. The bags were placed in my unheated greenhouse. I should have logged the temperatures perhaps, but I didn’t (I’ll do that next year). The greenhouse vents are set to keep temperatures around 21-23°C (68°-74°F), although temperatures may have risen above this at times. There was no heating however, so temperatures during night will have gone down quite a bit as well. Last year I did the same treatment, but temperatures were not as high then and rooting occurred later, although here as well I don’t remember exactly when.

I am not sure about the exact treatment as well. I did receive some seeds later in the season and hesitated what to do with them. Place them in the greenhouse as well, although with decreasing temperatures they may not receive a long enough warm treatment. Or place them inside in a room where I can give additional heating? I’ve split them, but as it’s only a few seeds, I doubt much can be concluded from it if I would get some roots.

What I also wonder about: in the greenhouse they actually receive both warm and cold during the ‘warm period’. That’s more like will happen in nature of course. I have noticed that some of the seeds already had a plumule growing. So those must already have received their required cold period as well. Perhaps it’s thus possible to give both warm and cold period at the same time? Which is not necessarily very beneficial of course, I cannot plant them outside as they risk being frozen resulting in early death. And for some I do think outside planting after the first roots might be better, in pots there is always more risk of loss is my experience.

But what I reallly wanted to say: what would be best? Continuous warm temperature (as you would have inside) or alternating warm/cold temperatures, with probably the warm daily temperatures rather warm enough and for a long enough time? There sure is some more experimenting to do. But it will be for next year… I didn’t really mind all the failed germinations from Just Peachy. If not for this experiment I would never have collected the seeds at all.

I think the brown tips at the growing point of the roots are from too much moisture. If it were lack of air, I’d expect it to see at random throughout the experiment, which wasn’t the case, it deteriorated with increasing moisture levels.

The ruptured seeds I threw away weren’t necessarily bad, but I wanted to rule out the possibility that they would influence the results if they germinated less well or otherwise compared to ‘normal seeds’.