Temperature drop to initiate flowering
 

how long of a period with cooler nights is needed to initiate flowering?

the only way i can achieve a good temp.drop now is messing with the central heating and a window ajar. since the outside temperatures went freezing it's become quite a handful to control it all "manually" (getting up at night and so on..)

will my phals get the hint in 2-3 weeks or do i continue with my new nightly routines until i see a spike? :dumb:

I didn't do anything special with mine. Just the switch to central heat from high daytime summer temps did the trick. They get approx 17 C night and about 21 C daytime. When sun shines (rare these days) the day temps are a bit higher, say 25 C. They are spiking just as normal.

It may take a few more weeks. Besides the cooling "treatment" a couple other factors can help - let them go a bit dryer than normal before watering (slight stress) and a little more light than normal (if possible).

Yeah, forgot, mine are a bit dryer and possibly the light is brighter when the sun shines.

we won't be getting a big day/night difference before it's REally cold outside and i turn the radiator off, the ambient heat from other rooms keeps the small room warm too. that's why all the trouble. i guess our houses are built against the cold too well, from an orchid's point of view at least..

anyway, I appreciate your tip, i'll hold back the watering a bit.

I'm not sure if this would work or not but you could try laying some of those blue ice cold packs near your plants. Not close enough to freeze them obviously, but close enough to cool the air near them. Then you could stay in bed at night! ;)

If your windows have curtains (or you rig something up), you can place the plants between the window and curtain. It creates a cooler microclimate. I use this alot with my cyclamens to keep them cool so they bloom longer.

I've noticed frozen bottles rob the air of humidity as they warm up, i'd expect ice packs to do the same.
to be honest, my 7-month old son wakes me up most nights anyway, so checking up on the other room isn't as tough as i may have implied earlier.:)
this night though after cooling the room i'll try closing the window and tucking in some towels under the doors to store the cool air. maybe that'll be enough.

EDIT: thanks Camille, but i'm hoping the Aerangis in my tank might get inspired by the cooler nights too..:evil:

That should do it. You really only need a few degrees difference. Not more than 10 degrees for a month or so should do it, and then only at night. Day temps can go back to what you are used to. Just my opinion, of course :biggrin:

(Maybe I missed something, so bear with me...)

WHOA!!!

• Not all plants bloom in response to cooler temperatures.
• Some that do respond to day/night temperature differences, others respond to a general decrease in overall growing temperature.
• Some respond to changes in daylength, but as that occurs coincident with lower temps, we associate it with that, by mistake.
• Some view the cooler temperatures as a death threat, so bloom as a last-ditch effort to carry on the gene pool. (I'll admit that's a stretch, but it IS possible.)
• In nature, a cooler period can be accompanied by reduced rainfall, so the plants respond to that, and the coincident "other" conditions may not play a role at all.

So then... what kind of plant are we talking about, anyway?