Cattleyas under lights?

[missann]

I just recently read that with certain species of cattleyas-the one mentioned is c. trianaei- that you can get them to bloom twice a year simply by adjusting the day length with artificial lights. It didn't mention skinneri though, and I have just divided my 'heiti jacobs' FCC clone and I wanted to do some experiments with it. Since it is a spring bloomer, I have a while until I get to see the show so I thought that with all my plant lights and having a space to do this, I might try it. I just don't know how long I should simulate winter for, and if it will even work on skinneri.

I have also read somewhere that some of the unifoliate cattleyas will not flower unless they have 8 hours of uninterrupted darkness.

I am just curious to know if anyone has done this, and, if you grow cattleyas under lights, what kind of schedule do you use to do it and how long of a rest period do you give them to simulate winter?

I have the following light duration schedule in a book that says (for general culture) nov.-jan. 16 hours/day;
feb-june 18 hrs/day
july-august-16 hrs/day
sept-oct. 12 hrs/day

Oh yeah, I have them in front of a window as well as under lights because the light from the window is not as bright as it needs to be.

[isurus79]

Im curious, what book say that cultural daylength for Catt should be between 12-18 hrs per day? Especially at the monthly intervals mentioned? I ask because those hourly changes dont represent any earthly time frame. Your longest hours are from Feb-June when the longest day in the N hemisphere is in the middle of June and the middle of December in the S hemisphere. Not to mention the shortest daylength inveral occuring in the middle of fall. Why not just follow your natural daylenth changes where you live? Set your timer to approximate the rising and setting of the sun in your particular city. It just seems strange to me to try and replicate a lighting scenario that does not take place anywhere!

[smweaver]

That does seem to be a lot of hours of light. Eighteen hours? Is that possible anywhere in nature--even at the equator? Guess you could try experimenting if you have some plants that are stubborn and refuse to bloom. As far as uninterrupted light being necessary for flowering some of the unifoliates, did the book you have indicate which unifoliate species are that sensitive? I have Cattleya labiata, mossiae, gaskelliana, dowiana and leuddemanniana, and none of them have shown any reluctance to flower even though I go outside and inspect them nightly under the porch lights during the warmer months when I'm on slug and grasshopper patrol. I also spend too much time at night reading in the sunroom during the winter with all of the lights turned on (and possibly surrounded by resentful cattleyas that wish I would go away and turn off the lights) without any noticeable harm. Maybe there are some plants that are that finicky about light requirements. But all of the ones I've grown have been pretty adaptable and (thankfully) forgiving.

[Orchid313]

I am blooming Catts under lights, both species & hybrids using wide spectrum bulbs under the following schedule that mimics the natural cycle : Feb-Apr 14 hrs; Apr-Aug 16 hrs; Sep-Oct 14 hrs; Nov-Jan 12 hrs.

[Brooke]

C. labiata is the only species catt I know that needs a reduction in light to bloom. It is a late fall bloomer.

C. triannae is a late winter/spring bloomer. It needs a reduction in water, not light, to bloom it successfully. It should have sheaths in place now for bloom later. I've never known or heard of a triannae that bloomed twice a year. I've had them grow new leads at the wrong time that didn't produce sheaths when brought from the southern hemisphere to here but not bloom.

If you divided your skinneri, I doubt you will get bloom next spring. It needs higher light in the winter than the summer and also a reduction of water during the winter.

What are the name(s) of the books you are using.

Brooke

[missann]

The book suggests that you leave the lights on longer to make up for the fact that they are not getting as high of intensity light as they would be in nature, thus making up for the light difference.

I can't remember the names of the authors of the book, but it was titled, 'orchids'- it could be one of a hundred. Anyway, I would look for you, but I took it back to the library the other day. Um..Isurus, I thought that the day length/time frame chart was weird as well, so I have just let the lights stay on a few hours past sunset to mimic nature.

SMWEAVER, yes, there are places (the north and south poles) where the day length is 18+ hours long, including Alaska, where orchids like cypredium (sp) grow wild. Day length is much shorter (than other places) near the equator year-round. I used to live in Hawaii, and it really bothered me how short the days were there compared to Idaho. As far as I can remember, the book did not mention what unifoliate cattleyas need 8 hours of uninterrupted darkness at night.


Orchid 313 thank you so much for letting me know what schedule you use.

[entropy82]

food for thought. i experiment with many light regimes on ALL of my 34 different plants. 16 of which are different orchids, which are relatively new to me. the earth only rotates completely 5 times in a 7 day week. (i think i said that right) so you can play with some funky light schedules, especially if you have a photo period sensitive plant. for example, if you have a plant that needs 12 hrs a day of dark in order to bloom, then typically you would use those other 12hrs a day to give it light. doing this for one week gives it a total of 84 hrs of light, and 84 hrs of dark. but i suggest this. try setting your timer (digital, 7 day , blah blah) to cycles of 21hrs 36 min of light on, and 12 hrs of light off. doing so allows you to have only 60 hrs of dark (but enough to trigger blooming) yet you get 124hrs of light on the plant when we consider the same 1 week time period. basically you can keep the lights on a lot more. now you can grow more shade intolerant species, and now you can focus on other limiting growth factors and get some incredible blooms.

[entropy82]

whooops-minor calculation error. using the 21:36/12 schedule, that would be 60hrs of dark and 108hrs of light per week. NOT 124hrs of lights on, but i'm sure there's a way to make that happen if you really want. feel free to experiment.

[Ross]

I have been growing under lights for a while now and I find that the shortest "day length" necessary is about 11-12 hours and the longest necessary is 12-14 hours. Anything outside this range doesn't create any significant change in the plants. This also corresponds to Northern latitude day length.

Now as to the original question about adjusting daylength to get flowering. That seems like a test for Mythbusters to me. I find that Cats and other orchids will bloom when they get done maturing the growths - plain and simple. No way, I've seen to trick them into any other plan. When they're ready, they're ready. Simple as that. I strongly doubt day length or night length has any significant affect. As for 8 hours minimum night length - that might be true. Why not provide at least this? All my orchids are under lights and I run the lights for 11 hours right now up to 14 hours at heat of summer. Nobody gets a reprieve from this regimen! Not even my neighbors! I get frequent blooms and I get what I feel are blossoms on schedule.

[entropy82]

Ross - what kind of lights, PAR, etc?