I’m worried. My 8 month-old JBP seedlings are turning purple. I’m in USDA zone 6. It’s end of November. Is this normal? Will the needles return to green in spring?
Yes, this is normal, the seedlings are reacting to the cooler temperatures in the fall, they should be protected from freezing at this stage. They turn green in the spring and resume growth if the roots are not damaged during the winter.
Thank you very much for the reply… very relieved to hear that. This is my first year as a bonsai enthusiast. You mentioned to keep them from freezing. I have them in a cold frame, inside my shed. Is that sufficient protection? I’m pretty sure there will still be some -10C temperatures in there. Your reply would be beyond appreciated.
At this early stage they should be protected from freezing. I use a small heater that only operates when the temperature reaches 2 degrees Celsius or approximately 4 degrees Fahrenheit. The heater brings the temperature up about five degrees and then shuts off. This allows the plants to have a dormant period but not kill the sensitive roots of the seedlings. These heaters are sold specifically for greenhouse application.
I have not tried to winter JBP seedlings without protection the first year so cannot say how many or if any would survive -10. They have done well without winter protection after the first year.
Hope these comments help.
They certainly do help. Thank you very much for that. I just might have to invest in a heater then. Hate to lose these seedlings now after tending to them since March. I got big hopes for these guys… Thanks again.
One additional thought, the brand name heater i am familiar with and has functioned well for me is Caframo. not sure if it is available in your neck of the woods but it is likely available online.
Ok, that’s great… i’ll certainly keep that in mind. For now, i’ve decided to let them brave out the winter. I may regret that in spring but if any survive, i’ll be real proud of them…
I understand. If you have the time, keep track of the coldest temperature range and how long it lasts. More information helps us all. The cold frame is a definate plus.
Best in bonsai
So the cold frame is a Palram Single ($50). I hope it does the job this winter. It seems perfect for what i’m using for. It fits my seed tray and a few other pots. I would, however, hesitate to trust it in the elements. It’s not the sturdiest… hard to imagine it holding up with a foot of snow on it.
I’ve got the temp & rh% gauges in there. I’ve got everything surrounded by pine bark, right up to the trunks.
I do monthly videos on Youtube if anyone’s interested… JD’s Bonsais. I’ll definitely be covering their progress through the winter. Just a heads up, i’m not much of a commentator or cameraman…