Quote:
Originally Posted by DeaC
...saw neos outside dusted with snow in Japan. Made me think my indoor temps were too warm but you have success with even warmer temps....
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When it comes to the temperature thing, the winter dormancy does help better flowering, and in a few particularly difficult varieties, seems to be the best way to induce regular flowering after ensuring that the plant is getting enough light.
In regards to the temperatures that the plants can safely be put through for dormancy, my research and experience shows that in the winter, the lowest temperatures that are safe for Neos depends on two things: 1) the origin of the variety and 2) the level of dormancy it has achieved before putting it in low temperatures.
In regards to the origin of the variety, there are the varieties from Mainland Japan and the varieties from the Nansei Islands.
The Nansei Islands are all of the islands south/west of mainland Japan and include Amami and Okinawa. Any variety from those areas are said to be unable to withstand temperatures below 40F.
Neos from the mainland of Japan on the other hand can withstand lower temperatures. However, the temperature they can withstand depends on the level of dormancy they have achieved before being subjected to the temperatures.
Dormancy for Neos can range from simply the roots closing off and all growth halting, all the way to the leaves wrinkling and folding up. Many growers in Japan will go all the way to an extent that most western growers would be horrified to see. Korean growers on the other hand tend to not go anywhere near as far, though possibly it's because of the popularity of Amami varieties there.
In any case. If the dormancy level achieved is simply the roots shutting off and the growth stopping, you should keep the minimum winter temperature at 40F. NEVER let it go below freezing at this stage.
If you put it through full dormancy and the leaves have folded up, they are said to be able to withstand temperatures down to or lower than 28F because what remaining water in the leaves has its freezing point lowered by the sugars in the plant. However, the only real way to put them through full dormancy is to grow them outdoors in a shade house and expose them to the full cycle of moisture and temperatures from fall through winter. It is a gradual process and it is difficult to control an artificial environment just right to get them to go fully dormant.
All that said, most growers agree that it's not necessary to put a neo through full dormancy to grow them to their best. Keeping the winter temps for them between 50 and 60F is usually enough to get the near maximum benefit of winter dormancy.
Many Japanese growers go all out to full dormancy simply out of convenience. They don't have space to bring them all inside, or build a full greenhouse for them, and their outdoor temperatures rarely drop below the minimum safe for Neos at this stage, so they just let them grow outside.
Korea in general is a much colder country than Japan, so most Korean growers do not have the option of growing outside year round. Because they already have greenhouses or have to bring them indoors, they put their plants through minimal dormancy, keeping the plants at temperatures in the winter around 50F and avoid full wrinkling/folding of the leaves.
Finally, in regards to my own habits, I personally have little issue with flowering most of my varieties even though I grow indoors and my winter temperatures never really drop much below 70F. They flower decently well, and while I know I can get them to flower much more prolifically if I gave them a deeper dormancy, I'm actually quite happy with how they do as they are now, especially since flowering isn't the top priority for the majority of my collection.