Seasonal changes for Cattleya growing conditions

[terryros]

Mixing metaphors, during the last year, I went down the rabbit hole and into the weeds with the issue of seasonal changes in growing conditions for Cattleyas. I purchased the Baker culture sheets for my thirteen unifoliate Cattleya species because they were the most detailed information I could find. The monographs showed that the in situ conditions of my species differ substantially.

They range geographically from about 10 degrees N latitude to 30 degrees S latitude, which affects their seasonal day length and light intensity. They also vary considerably in their seasonal temperatures and rainfall. I have done what was practicable to customize my indoor growing conditions to match these seasonal changes, knowing I had a dilemma.

Could conditions different from those in situ achieve even better growth and flowering for some species?

A Cattleya species must have evolved in a specific habitat because it provided the best overall survival. However, survival means more than growth and flowering; survival requires pollinator availability, conditions for seeds to germinate and grow, and other things. Some species may have found where they could compete better than other local plants for light, water, nutrients, or avoiding elements of destruction.

I know that monocotman has been getting excellent growth and flowering in his new plant room with only modest seasonal changes in growing conditions. William Rogerson indicated success with this approach in a 2015 Orchid Digest piece about growing Cattleya species in his Chicago, IL greenhouse when he said, “I find that my … plants do better when I maintain a nighttime temperature of 65 F (18 C) in the winter and a daytime temperature of 75 F (24 C),” Rogerson is an outstanding grower with numerous flower quality and cultural awards.

I have decided to escape my dilemma and take the easier road: use only moderate seasonal changes for my Cattleya species and see what happens. No more 53-55 F (12-13 C) nighttime temperatures in my plant room next winter, trying to frighten some species into growth or flowering.

 

[monocotman]

Terry, some interesting thoughts.
Just a comment about the conditions that a species grows in, in the wild.
A species does not necessarily grow in the ‘ideal’ environment.
It grows in one where it can outcompete all the other species capable of growing in that particular niche.
So it is very possible that a species can make ‘better’ or more rapid growth in another more benign environment.

 

[NEslipper]

Some additional food for thought, some large unifoliate species have been line bred for many successive generations at this point (think trianae stud plants that have been around since the 19th century). There was initially a significant genetic bottleneck in selecting for plants that could survive being ripped off a tree branch, shipped in a crate for a few weeks across the Atlantic, and then grow, bloom, and set seed in a hothouse in England. Only the most vigorous and floriferous would be successful. Over 100+ years of line breeding is going to put additional selective pressure for plants that can grow and bloom in a greenhouse. I like to think that some of these line-bred species are quite well-adapted at this point to pot plant culture. A more recent example of this would be some of the multifloral paphs like rothschildianum and sanderianum. They have long had a reputation as being extremely difficult to grow and bloom, and until very recently weren’t the focus of diligent line-breeding, but even with just a few generations (F2-F4) plants can grow and bloom reliably on a windowsill. I tend to not worry too much about trying to perfectly mimic “natural” conditions, since I do grow primarily on windowsills, but I’ve been able to bloom rothschildianum, sanderianum, stonei, philippinense, micranthum, lueddemanniana, mossiae, and trianae all growing on the same windowsills. I’m certainly not flowering them to their absolute best, but I’ve generally found orchids to be highly adaptable and rewarding.

 

[terryros]

You both are supporting that mimicking in situ conditions may not be right for our current plants.

 

[DrLeslieEe]

Besides temperature and feed, I think what is missed here is the number of hours (and intensity) that plant respond to in their environments. That is one of the Holy Trinity of successful flowering.

 

[terryros]

Besides temperature and feed, I think what is missed here is the number of hours (and intensity) that plant respond to in their environments. That is one of the Holy Trinity of successful flowering.

Leslie, are you saying give longer hours and higher intensity light than in situ?

 

[DrLeslieEe]

Leslie, are you saying give longer hours and higher intensity light than in situ?

No, I'm saying manipulating up or down that variable will trigger better blooming.

 

[Stefan Neher]

Mixing metaphors, during the last year, I went down the rabbit hole and into the weeds with the issue of seasonal changes in growing conditions for Cattleyas. I purchased the Baker culture sheets for my thirteen unifoliate Cattleya species because they were the most detailed information I could find. The monographs showed that the in situ conditions of my species differ substantially.

They range geographically from about 10 degrees N latitude to 30 degrees S latitude, which affects their seasonal day length and light intensity. They also vary considerably in their seasonal temperatures and rainfall. I have done what was practicable to customize my indoor growing conditions to match these seasonal changes, knowing I had a dilemma.

Could conditions different from those in situ achieve even better growth and flowering for some species?

A Cattleya species must have evolved in a specific habitat because it provided the best overall survival. However, survival means more than growth and flowering; survival requires pollinator availability, conditions for seeds to germinate and grow, and other things. Some species may have found where they could compete better than other local plants for light, water, nutrients, or avoiding elements of destruction.

I know that monocotman has been getting excellent growth and flowering in his new plant room with only modest seasonal changes in growing conditions. William Rogerson indicated success with this approach in a 2015 Orchid Digest piece about growing Cattleya species in his Chicago, IL greenhouse when he said, “I find that my … plants do better when I maintain a nighttime temperature of 65 F (18 C) in the winter and a daytime temperature of 75 F (24 C),” Rogerson is an outstanding grower with numerous flower quality and cultural awards.

I have decided to escape my dilemma and take the easier road: use only moderate seasonal changes for my Cattleya species and see what happens. No more 53-55 F (12-13 C) nighttime temperatures in my plant room next winter, trying to frighten some species into growth or flowering.

I can only speak anecdotally to my own collection, but I pay absolutely no attention to species-specific conditions on a season-season basis, and I get flowers every year at the same time (almost to calendar date).

What I do differently than most is leaving ALL Laeliinae (except Brassavola species/hybrids) species and hybrids outside almost until freezing, but with dry substrate. They also go right back out once temps stay just above freezing (35°F) . . . My reasoning is two-fold: Cold temps induce anthocyanin protection in the same way intense light will, but sunce my winter setup under LEDs doesnt get them there, this early season/late season boost seems to help with prevention/protection against the harsh harsh sunlight we get in midatlantic’s March (zone 7b just outside DC).

Additionally the cold temps helped me combat pestilence in tandem with topical treatments, as most of our common pests (mealys, thrips, mites) despise cold temps and will either die, reduce, or go dormant in such conditions, buying me time to repot and treat plants before bringing them in.

The only other non-traditional thing I do for my Cattleya group (i have many Rlc as well) is basically maintaing active growth all winter since I have temps and LED supplementation inside. They almost always stay moist, and get fert/horomone/cal-mag treatments every 2-3 weeks.

Hope this offers some insight to OP question/ponderings.

 

[terryros]

No, I'm saying manipulating up or down that variable will trigger better blooming.

That road says that some seasonal variation in day length, light intensity, temperature, water, and nutrition is probably necessary to trigger growth and blooming in some/most/all species BUT, they may not need to be as extreme as occur in the natural habitat.