Cool down period... enough to trigger new growth? - Orchid Board

cythaenopsis · #1 08-29-2011, 11:18 AM

I couldn't help but notice that we've finally started dipping down to around 60 degrees at night in the NYC area. The forecast looks to have this consistent for the next 5 days, possibly longer. Will this be enough to help trigger new growth in orchids exposed to it? I'm leaving my orchid growing window open at night, so a cooler breeze is now coming through. Are there any tips to consider at this point to help boost healthy growth?

camille1585 · #2 08-29-2011, 11:57 AM

What kind of orchids are you talking about? I know that you posted about a phal, but wondering if you have other types as well. The cool down period isn't really so much for growth, it's for flower induction.

Paul Mc · #3 08-29-2011, 01:27 PM

Phal's yes and maybe other types, but for many others they need lower. Some even need near freezing. What types are we talking about. Please give full names if possible as even in one type the temps can vary drastically.

cythaenopsis · #4 08-29-2011, 03:42 PM

Ah, sorry -- didn't mean to pull a newbie (flower question without mentioning the species). I should have been more specific.

I've got 3 phals, all without flowers. One has a cut spike from the early summer and the other still has original spikes and branches intact (didn't yellow, stayed healthy). The last one has just one spike that is a dried stick, but otherwise healthy leaves and just so-so on the roots (had to cut off quite a bit of rot).

The 3 other orchids I have are an Encyclia, Oncidium, and Sierra Skies; all very young. Unfortunately the vendor had very little information to offer about care.

camille1585 · #5 08-29-2011, 03:57 PM

Phals need a general cooling down for several weeks in order to set spikes. This means that both night and day temps have to be a few degrees lower. It's a common misconception that it's a reduction in only the night temperature that induces spikes. But this overall decrease in temperature is very easy to obtain inside usually if you don't keep the temperature too steady with AC or heating, the natural cooling down in early fall usually takes care of it. Make sure that they're getting good light, not enough light is more often the cause of not blooming.
In my case the Phals set spikes early since April, may and june were very summery, but July was cool. I started seeing spikes in August!

I'm not sure about the other orchids though.

cythaenopsis · #6 08-29-2011, 04:02 PM

^ I understand now about the temperatures, so I'll be sure to hold back my expectations.

Nice going, getting your phals to spike so early.

Do you have orchids in both living locations? I imagine Lyon must provide for some amicable conditions for orchids, plenty of outside time.

glengary54 · #7 08-29-2011, 04:04 PM

As Camille hinted at in her response, Phals need a difference of 15-20 degrees between daytime and night time temps in the Fall (for a few weeks) to initiate spikes for the following Spring. Many other genera experience a slightly cooler winter in their natural habitat but don't really need it in order to bloom. Others require a cool, dry winter rest. Out of what you have mentioned above, only the Phals need the cooler temp to help them to rebloom next year.

camille1585 · #8 08-29-2011, 04:14 PM

Quote:

Originally Posted by cythaenopsis

^ I understand now about the temperatures, so I'll be sure to hold back my expectations.

Nice going, getting your phals to spike so early.

Do you have orchids in both living locations? I imagine Lyon must provide for some amicable conditions for orchids, plenty of outside time.

Actually, since a few weeks ago I'll be in the Netherlands full time for the next 4 years (doing a PhD). For the previous 5 years I've been going back and forth a lot for school. Sometimes I spend a few weeks in France, sometimes a few months. Between Lyon and Wageningen the difference in conditions is like night and day! Here it's yucky cloudy rainy weather from october to march, not good for the orchids. AND I have a north window.... In France they spend the summer outside under shade cloth, or in our basement behind huge windows. The more recent part of the house (100years or so) was built so that a silk weaving machine could be put in the basement. That needs high ceilings (11-12ft I would say) with nearly floor to ceiling windows. They face south, so it's almost like a greenhouse for the plants!

A shame that they will no longer get to enjoy it...
Anyway, I've written enough off topic!

cythaenopsis · #9 08-31-2011, 04:16 PM

^ What a wonderful diversity of places where you stay, Camille. *4* years in the Netherlands? What are you studying there?

The newer addition of your house in France sounds fantastic for plant growing. No wonder why you have such an enormous diversity of orchids. I just started checking out your photos--most impressive!

camille1585 · #10 08-31-2011, 04:43 PM

I like the Netherlands, partially because everyone speaks English! Even with french parents I never really adjusted to french life after being born and raised (15 years!) in the USA.

I'm in plant science. Started college studing horticulture in france, then moved into plant breeding for 2 years, and then discovered plant pathology. So now I'm working in plant-insect interactions, basically studying how a plant's "immune system" works via it's hormones.

But even with all this plant knowledge, orchids were a steep learning curve when I started since they're so different from 'normal' plants!