Grow Tent Orchids

[isurus79]

Originally Posted by Dusty Ol' Man

The bottom of my tent s open to the room. The a/c is on so the humidity in the house is low to begin with. I only have four (soon to be five) plants in it, though I may change that next week. I wonder if I move the fan up and change its direction if the humidity will increase? When I first set it up as it is, but without the fan, the humidity got up to 90%
And during the fall and winter the humidity down here can get very low. As in the mid 30%s.

Sounds like a pretty good set up! I didn't realize the humidity get so low this time of year!

---------- Post added at 10:44 PM ---------- Previous post was at 10:27 PM ----------

Originally Posted by Shadeflower

since you bring up the nobilior. Does the rest mean the plant does no growing in this time? And then as soon as you see a new pseudobulb forming you start watering more again?

This species is an odd one. It grows in possibly the most extreme environment of the Cattleyas, with close to half the year lacking rainfall. The spikes can start as early as November (my tipo should open blooms in a week or two, albeit VERY early!) but typically start in January and open from February through March.

In previous years I wouldn't water from November through April, which resulted in blooms. However, a Brazilian friend of mine who lived in nobilior habitat told me that such extremes should be relegated to nature and that the species gets regular fog during the dry season. Growers who watered less frequently, but somewhat regularly get better blooms. Now I water them (and the walkerianas, which are in similarly xeric, though less extreme environments) once every few weeks. I get MUCH better blooms with this method. I also don't see any bulb shriveling, which means I'm walking the line of giving a drier winter rest to trigger blooming but I'm not crushing the plant's stockpiles of stored energy. I feel like it's a fine line to walk, but certainly worth the effort.

I don't think that any other Cattleya is this extreme in it's growth cycle, but nobilior might be a good example of how a dry winter rest can be beneficial. I'm taking the warscewiczii plant to an extreme place (I've only watered once in 5 weeks or so), but it gives me a baseline where to start. By figuring out how dry a plant can go without dying, I can better understand a difficult plant's needs.

Of course, I'm using a 'Bedford' cross where my flowers look nearly identical to 'Bedford' which might not be the representative of the whole species. C. warsc. has several regional variants and 'Bedford' is kind of an oddball. Either way, I have a bunch of coerulea seedlings coming of age, so I might get a better understanding of the species with those plant. It's fun to figure out the cultural details of each species! Some are easy and some are tricky.

[K-Sci]

Originally Posted by isurus79

I suspect there is some chemical trigger that only happens during dry dormancy. Or the Chadwick advice is not true. Either way, the blooms this summer will let us know! If they're the same as previous year (weak) then the Chadwick advice isn't applicable to my conditions and I'll have to figure out when else is going on.

I think your last sentence is right on. What works for some, may not work for others. What makes determining optimal orchid growing conditions hard to nail down is that it is hard and rare for one variable to changed at a time.

A few decades ago I tried to grow C. warscewiczii without flowering successes in a greenhouse 1-1/2 hours south of Seattle. The summers were too cool, day/night swings too shallow, and direct sun would shine only a few days a year. Here in Mississippi it is probably not too different from Texas. The summers are hot, day night temperatures swings are the ideal 15-20F, and sunlight is abundant.

I'd say the rest is more related to not providing conditions for rot (e.g. excess moisture, nutrients) when temperatures are low for the home grower and overwatering is easier to do.

I often wonder why a couple weeks of unseasonably cold wet rainy weather doesn't wipe out entire orchid species.
-Keith

---------- Post added at 12:03 PM ---------- Previous post was at 11:48 AM ----------

Originally Posted by isurus79

I suspect there is some chemical trigger that only happens during dry dormancy. Or the Chadwick advice is not true. Either way, the blooms this summer will let us know! If they're the same as previous year (weak) then the Chadwick advice isn't applicable to my conditions and I'll have to figure out when else is going on.

I think your last sentence is right on. What works for some, may not work for others. What makes determining optimal orchid growing conditions hard to nail down is that it is hard and rare for one variable to changed at a time.

A few decades ago I tried to grow C. warscewiczii without flowering successes in a greenhouse 1-1/2 hours south of Seattle. The summers were too cool, day/night swings too shallow, and direct sun would shine only a few days a year. Here in Mississippi it is probably not too different from Texas. The summers are hot, day night temperatures swings are the ideal 15-20F, and sunlight is abundant.

I'd say the rest is more related to not providing conditions for rot (e.g. excess moisture, nutrients) when temperatures are low for the home grower and overwatering is easier to do.

I often wonder why a couple weeks of unseasonably cold wet rainy weather doesn't wipe out entire orchid species.
-Keith

[Dorchid]

I grow all my orchids in the tent with the exception of my phals which live in the bathroom. Everything seems to grow fine for the most part but I really don’t have a reference point as this is the only experience I have. Temp is 67 night - mid to high 70s day with around 80% rh. I run a fan 24/7 and decrease photo period by a couple hours over the “winter” months (14 summer/12 winter). The one plant that is currently stumping me is mo. Painted desert x ctsm John c burchett…it doesn’t seem to want to flower. This is the second season I’ve had it and it produced a 17” growth this year. Not wanting to hijack the thread but thought this might be a good addition in relation to seasonal requirements and shortcomings with a tent.

[isurus79]

Originally Posted by K-Sci

I often wonder why a couple weeks of unseasonably cold wet rainy weather doesn't wipe out entire orchid species.

Either they don't get cool weather in nature or the cool weather on our collections is the straw that broke the camel's back, likely just being the tip of the iceberg of cultural problems in our artificial environment.

---------- Post added at 12:51 PM ---------- Previous post was at 12:50 PM ----------

Originally Posted by Dorchid

I grow all my orchids in the tent with the exception of my phals which live in the bathroom. Everything seems to grow fine for the most part but I really don’t have a reference point as this is the only experience I have. Temp is 67 night - mid to high 70s day with around 80% rh. I run a fan 24/7 and decrease photo period by a couple hours over the “winter” months (14 summer/12 winter). The one plant that is currently stumping me is mo. Painted desert x ctsm John c burchett…it doesn’t seem to want to flower. This is the second season I’ve had it and it produced a 17” growth this year. Not wanting to hijack the thread but thought this might be a good addition in relation to seasonal requirements and shortcomings with a tent.

You might want to take it down to 10 hours in winter. I bet that triggers blooms for you!

[Dorchid]

I shall give it a try!

[Steve83]

I think you'll enjoy growing in a tent. Here's an updated pic of my 4'x4'

Meet Google Drive – One place for all your files

[DavTom]

Originally Posted by Ray

I am curious why they make tents with a silver interior, rather than white.

Matte white absorbs and re-emits all wavelength of light in all directions, maximizing the dispersion of photons. A silver mirror reflects it only at the (opposite) same angle with which the incident beam hit it, which for overhead lighting, means down to the floor.

A textured, silver fabric is somewhere in-between, offering more scatter than a mirror, but it absorbs some of the light without re-emitting it.

Hi Ray. I see your point. But I have watched many youtube videos from apparently independent parties in which all kinds of materials were used and measurements were taken in many different spots with a professional/calibrated PAR sensor. The textured silver fabric provides the highest available PARs, but this is true only for the good quality ones, which are quite expensive. However, a nice flat white surface provides almost the same PAR (about 5% less, or so). So the question is: is it worth it to spend more money for that?

In my small stealth growing cupboard. which has white surfaces, I eventually installed the mylar. I did some measurements and I got slightly better results than the white surface. I did it only because the mylar is very cheap, otherwise it would have not been worth it...

Dav

[Ray]

I’ll bet you made your measurements in a mostly empty enclosure.

Consider the following scenario - the grow tent is 2 meters tall, by 1 meter wide and deep, and light source is a point emitter in the very center of the ceiling. Physics tells us that if the surface is mirror-like, light striking the wall 1 cm from the top will be reflected at an equal angle to a point 2 cm below the lamp in the middle; light striking the wall 2 cm below the ceiling is reflected to 4 cm below the lamp in the middle, and so on, until light striking the wall below the 1-meter mark gets reflected to the floor, never reaching the center of the floor. That’s probably OK, as there has been light reflected from all points on the entire interior surface, plus that going, unreflected, directly from the light source.

Sounds good, right? Maybe not…. Now let’s put plants in the tent. Light striking them goes essentially no further, whether that is direct, or reflected off the walls, making the volume below them darker - that ray of light that might have struck the wall at 50 cm down the wall no longer reaches it, so the plants at the 1 meter height never see it.

If, on the other hand, the walls were matte white, the light hitting them is no longer reflected at an equal and opposite angle, but is absorbed and reemitted in all directions. That means that while that “50 cm ray” is still blocked by the plant, preventing it from reaching those below, those rays striking the walls above and below that point are scattered sufficiently to still reach the plants in the shadow from the plant above. Not only that, but light rays hitting the wall are also scattered upward, illuminating the undersides of the leaves, essentially creating a more uniform illumination throughout the tent - something mirrors cannot do.

This is an extremely simplistic scenario, as lights are not point sources, shelves block light, and no interior is a perfectly mirrored wall, but that actually makes the scattering effect of a white wall more important.

[isurus79]

Originally Posted by Steve83

I think you'll enjoy growing in a tent. Here's an updated pic of my 4'x4'

Meet Google Drive – One place for all your files

Shoot, I was unable to access the Google drive, but checked out your Instagram profile and saw the set up! Very cool looking! What type of light are you using?

---------- Post added at 07:23 AM ---------- Previous post was at 07:21 AM ----------

Originally Posted by Ray

If, on the other hand, the walls were matte white, the light hitting them is no longer reflected at an equal and opposite angle, but is absorbed and reemitted in all directions. That means that while that “50 cm ray” is still blocked by the plant, preventing it from reaching those below, those rays striking the walls above and below that point are scattered sufficiently to still reach the plants in the shadow from the plant above. Not only that, but light rays hitting the wall are also scattered upward, illuminating the undersides of the leaves, essentially creating a more uniform illumination throughout the tent - something mirrors cannot do.

Ray - I think you found your next new product for you website!

[Steve83]

Stephen, I fixed the link permission, not sure why it changes, maybe I need to use Flickr or something else.

Lighting is via two 100w HLG sabers dialed down to around 65w each.