My indoor growing area: incarnations 1 and 2

I built a place to grow my orchids back in February but just got photos posted today. Our place was octagonal, 18’ x 18’ (5.5m x 5.5m), with very limited outdoor space that was already brimming with a bulb collection. My first impulse would have been to set up an outdoor greenhouse, even if that meant to make one from scratch, but the situation made it so I was forced to grow indoors. As my ‘spiritual guide’ Tim Gunn says, “make it work” so I did . Thankfully 7 years ago I had experience growing under an HID light in a large bathroom, so I am familiar with the issues of overheating and dryness that comes with operating HID lights. I designed a structure that would fit into our small flat and hopefully not be an eyesore but also allow me as much control over the variables important to plant growth. It was 5’9” (1.68m) long (I was limited by the length of segments of the walls that made up the octagonal room) , 2’ (0.61m) deep (hard to reach anything if it were deeper) and 8’ (2.44) tall (the structure had to rest on an existing bench and still have room to accommodate the lights within it). Many of the greenhouse appliances I used in this projects I already had because they were from previous growing spaces.

Then we moved to a new place in town last month, so I had to take the whole thing apart (completely apart, so as to fit through the door!) and reassemble it. This time I have more space and it got me thinking that I could expand a bit without too much additional cost. I didn’t need any new equipment just some more building materials. I expanded the same chamber by 3.5' (1.07m) in length. I am still working with the same amount of light, but the plants are less crowded. A third light would truly optimise the new space but I feel pretty bad already about using 800 watts of electricity with the two lights. Poor earth! Guess I am making some use of my carbon credits for living without a car for so many years.

It has been a lot of work to figure out how to perfect the growing environment. I joke that I have had to provide for them everything but gravity, because at least with an outdoor greenhouse, HID lights are generally not required. A few times I did get frustrated thinking why I am working so hard to make this thing work, having left behind what I felt was a perfect growing environment in Upper Mānoa Valley. As it turns out there is never a perfect growing environment and there are upsides and downsides from place to place. Here are some advantages to growing in an entirely controlled environment.

1. I can control entry of pathogens with much more precision. In the wet tropics, spores are floating and splashing everywhere. I have seen tender things such as Aerangis hyaloides, while even grown under cover from rain, looking perfect one afternoon, and the next morning dropping all its leaves as if by black magic, having been killed at the meristem by some pathogen without any forewarning. These pathogens are not floating around the ordinary ambient air here in the SF Bay area, but if one does get loose in the chamber, I can zap it or adjust conditions to make it unfavourable for it to propagate.

2. I can control air movement. In my former outdoor growing conditions, some nights are very gusty even in spots that feel ‘protected’. This can stress-out tender, mounted monopodials such as my beloved angraecoids. By contrast there can be an entire week (or two) where the air is dangerously still (fungi love these times!) or worse, it can be both still and very rainy!

3. I can control humidity! Most of the time in Mānoa I had pretty good humidity and I was rewarded with luxuriant growth. However having more control makes it so much easier to re-mount things and establish cuttings with confidence because root growth is much faster and they are more numerous. Also plants hold more leaves at once and flower so much stronger.

4. Lux! Unlike growing outside where the sunlight intensity varies throughout the day, passing through clouds and trees, these electricity hogs are constant, resulting in faster plant growth.

Here is a list of my materials as I figure there may be some readers who will want to know:

Building materials:
- low-grade untreated lumber 2x4s and 2x2s (firring strips) all cut manually with a hand saw
(as a renter, I have to think short-term)
- metal structural connectors
- exterior grade wood screws (instead of nails for ease of inevitable disassembly)
- insulation aluminium fabric (water proof and reflective, infinitely more easy to work with than 8mm plastic sheets)
- aluminium adhesive tape (this tape does incredible things, I love it!)
- galvanised hardware cloth
- heavy duty galvanised staples
- corrugated clear PVC sheeting

Appliances:
- 2 Super Sun 2 reflectors (excellent)
- 2 Galaxy electronic ballasts (compact and super quiet)
- 1 400w sodium halide lamp
- 1 400w metal halide lamp
- Trion Herrmidifier 707U Atomizer (very disappointing product but I have made it work for me, also it's super loud!)
- MistKing Ultimate System with zip drip valve and solenoid valve
- Dayton exhaust blower
- Dayton 10” motorised intake vent
- S&P Soler and Palau 6” duct fan (great and not too loud)
- home-made evaporative cooler (CELdek pad)
- 4 - 6” fans (for basic air circulation)
- thermometer/hygrometer
- thermostat
- timers (one for venting, one for misters, one for humidifier, and one for lights)

I won’t clutter up this thread with pictures, instead here are links to the two flickr sets that document the original structure and how it is now:

Orchid Growth Chamber 1.0

Orchid Growth Chamber 2.0

I am keeping the temperatures on the warm side of intermediate and the relative humidity above 85% most of the time. I have tried out various humidistats, but none of them seem to come on until humidity drops to 75% and frankly I have worked too hard to build this orchid palace to have it below 80%. Instead I have the misters on timers that only come on for a few seconds. The humidifier is on all day, and comes on for 15 min on the hour at night. The small circulation fans run 24hrs a day and the exhaust fan/motorised vent exchange the air in the chamber once in the morning and once in the evening. The evaporative cooler is indispensable to cool the air without compromising humidity, while the misters and humidifiers complete my arsenal against low humidity. Originally I was under the impression that as long as the lights were cooled in their “shrouds” as they are called via a ducting fan, that this would be all the control needed to keep temperatures in the chamber from soaring above my max (88°F/31.1°C). Oh was I wrong! Now I use the same ducting fan instead to bring in the cooling from my evaportive cooler. I took a piece of flexible aluminium ducting, sealed one end and perforated it along its length, and then suspended it along the length of the ceiling of the chamber. This allows for a more even distribution of cool air when the cooler is operating. Another issue is the stratification of heat. If I don’t have the small circulation fans push the air from the ceiling down to the base of the chamber, the temperature differential from the ceiling to the floor can be as much as 8°F/4.5°C. Growing under the HID lights also makes having a light meter very important, because the intensity of light can be deceiving. It changes quite a bit just a few cm/in. closer or farther from the light source. I measure every spot in foot candles before I place a plant in it. I am usually surprised by the reading each time. I was a bit cavalier with some plants and they did incur sunburn as a result but they have since recovered. About 1’ / 30cm below the glass, the intensity begins at 6000 foot candles and if it is unimpeded bottoms out at 500fc at the base of the growing area (5’/1.5m from glass). The most 'expensive real estate' along the chamber walls are the strata where the light falls between 2500fc-1200fc. Most of the species I grow really prefer this range.

Now maybe you all can help me find a name for my growing area! I can’t find a word I am entirely comfortable with and don’t like calling it an orchid chamber. I would use “orchidarium” but that is apparently trademarked and I heard that company makes a stink if people who build their own use their name to casually refer to home-made creations. “Growth chamber” is usually used for the climate controlled cabinets growing research crops at universities. I equate them with beans, corn and arabidopsis and seems too bland for my Wonka-like contraption. I have toyed with “orchid jail” because it is made of so much metal it seems like a cage, but it makes it seem a bit more kinky than I would like. I am also thinking of calling it “orchid wall” or “orchid cabinet”. Sometimes my partner catches me calling it simply “greenhouse”.

 

Thanks Kelly! "Mist city" is funny.

 

Thanks Marni!

 

Thank you very much Alexis. I must admit I didn't think I would be learning so many new things by growing orchids in a box when I have had many years of experience growing in large greenhouses and outdoors both in Hawai'i and southern California. Life is such a funny thing, causing one to learn lessons in unexpected ways!

 

Great ideas, thanks!

 

Update: I moved my desk into the room with the orchid cabinet. It's a nice view. The light from the HID lights helps keep me from feeling deprived of sunlight in this foggy grey climate.

 

Thanks Marni and Peter!

 

Thanks Kitty, sorry I missed your post until now.

Did I mention that every time I open the doors of the growth chamber, a rich, heady 'greenhouse scent' pours out over and around me? It's a heavenly experience.

 

Thank you Brant. It was a lot of work but totally worth it.

 

Thank you Egoista, I appreciate your feedback. Your set-up looks good too

I was so lucky to find a piece of new, unscratched plexiglass set out for rubbish collection down the street from me a few weeks ago. With glee, I brought it home straight away. Today I cut it to size as a replacement to the clear, corrugated PVC window covering I had. It is so much clearer than the PVC. I love it. Now I am tempted to replace the other windows with plexiglass too!

Last week I switched placement of the sodium halide and metal halide bulbs between the lamps. I must say I am beginning to tire of the harsh orange glow of the sodium halide light. It is hard to tell which light produces better growth in the orchids. When I replace the bulbs later this year I think I will only get metal halide as it is infinitely more pleasant.

Here are some pictures taken this evening of the new window. The red flowers are of Renanthera monachica and if one looks closely, the newly-opened green Dendrophylax funalis flowers are also visible in picture n°3.