In the first installment of this series I talked a bit about lighting, and introduced the genus Phalaenopsis — the moth orchids. In the second installment I wrote about watering orchids, and introduced the genus Paphiopedilum — the Asian lady slipper orchids.
My little table in my north-facing picture window was doing okay, but it wasn’t going to serve me for much longer. I had two problems coming up to hit my new-found habit hard: the lack of light, and the addition of a cat to our family.
Back to Challenge 1, and Beyond
As I mentioned in my last diary, I wanted variety from my orchids, and soon I found myself purchasing orchids that required more light than I had available. I was also running out of space on my little table. And though I love my cat dearly, she liked to nibble on the leaves of the newest orchids I had purchased. I needed an indoor growing room both to protect the plants from the cat, and to provide a more controlled and happy environment for my growing orchid collection.
To be completely honest, I am just completing the build out of my second indoor orchid space; I’ll talk about that in a later diary. The first space was a cheap, small (3 ft. x 1.5 ft. x 6 ft.) “greenhouse” frame placed in a spare bedroom, minus its plastic cover. With only half of the grid shelves installed I could hang a high power 200W compact fluorescent grow light at the top along with some additional 32W CFL bulbs for the bottom shelf. The top shelf would house my new orchids with their higher light requirements, and the bottom shelf would keep my moth orchids and lady slippers happy. I had a cool mist humidifier, and the room it had its own baseboard heating that I could turn up every morning and back down in the evening. The lights plugged in to an industrial-looking power strip, which in turn was plugged in to a mechanical timer power plug. I added a fan for air circulation and cracked a window, and I was all set up!
The next step was determining the right height for the lights, and where each plant needed to sit in order to get just the right lighting. Hey, guess what? I’m a nature photographer! Measuring light — we do that sometimes… Well, I let my DSLR do the measuring for me, and it’s a pain to haul a full-sized camera around to figure out light fields under a lamp. Fortunately, there are apps for that. I use one called simply ‘LightMeter’, available for both iOS and Android. Photographers talk in terms of ‘EV’ (Exposure Value), with each +1 EV representing a doubling of the light level. Here’s a chart of the EVs relevant to orchid growing, at ISO 100 sensitivity:
EV at ISO 100 |
LUX (10 LUX = 1 Foot-candle) |
Orchid Lighting Category (Max LUX) |
EV Values For Orchid Growing
12 |
10,000 lx (1,000 fc) |
Low (10,000-15,000 lx) |
13 |
20,000 lx (2,000 fc) |
Moderate (15,000 — 30,000 lx) |
14 |
41,000 (4,100 fc) |
High (30,000 — 45,000 lx) |
15 |
82,000 (8,200 fc) |
Full Sun (100,000 lx) — too bright! |
Conveniently, LightMeter has an EV readout, and on many phones it will do incident light readings using the incident light meter on the front of your phone, which makes taking and reading the output quick and easy, if a bit more finicky.
At about 1 foot from the leaves of my orchids, the 200W bulb “only” reaches an EV of 13 — good enough for most Oncidium alliance orchids, but not really enough for Cattleya and Vanda species to thrive. Moving away to the edges of the small greenhouse frame, the light falls to EV 12 and below. Armed with this information, I added a couple of 32W CFL grow bulbs to the mix, which gives me more room at EV 13 and a bit of space at EV 13.5 for those orchids that like lots of light.
With artificial light you also get a bit of leeway. Instead of adding wattage, I could have added time to the “day” length. Orchids need overnight rest, but most will put up with a 16 hour “day”, giving them a chance to soak up 33% more light than a 12 hour day. I wanted to go with a more natural cycle — including varying the length of the day according to the time of year, which some orchids need in order to initiate a new growth and bloom season. You can also move your plants closer to the light, but I wanted to maintain a bit of space.
I chose CFL grow lamps when I moved my orchids under lights, but there are several types of artificial lighting that work for growing orchids. I haven’t had much chance to play with the others, but I’ll summarize the types and their pros and cons as I’ve read about them. I would probably start with LED track lighting if I had the time and money to get a full setup today…
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Incandescents: There are still incandescent grow bulbs out there, but they’re hot and not terribly bright for the wattage. The advantage of incandescent bulbs is that they put out what we consider to be a natural full spectrum of light.
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Fluorescents: Your average fluorescent bulb is pretty bad at growing plants, because the spectrum — while okay for people — is not optimized for plants. Plants need lots of red and blue light, while human vision is optimized for green. Fortunately, companies have spent a lot of time creating fluorescent “grow lights” that produce light more useful to plants. You can buy bulbs designed to enhance growth (6500K cool white light) and others designed to spur blooming (2700K or 3000K warm white light). You can buy bulbs to fit traditional T8 and T12 fixtures, but those models don’t have the best efficiency and are relatively low wattage, meaning you need a lot of them close to your plants in order to be effective. A better option is to purchase high-output T5 fixtures; each bulb in a T5 is 54 watts, and the bulb itself is more efficient than traditional T8/T12 models. These often come in sets for hanging over plant tables. T5s are expensive, though. Perhaps the best option these days are CFLs — compact fluorescent lights. You can purchase 25W and 32W CFL grow bulbs that fit normal light sockets; I installed mine in clamp-on reflectors available from Home Depot for under $10 each. Several companies also make higher wattage CFLs to fit “mogul” sockets, often with reflector shades to point more light down at your plants. Fluorescent bulbs are great because they are relatively cheap, and they’re relatively cool. Unfortunately, they also contain mercury...
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LED: LED bulbs are even more efficient than CFLs, but until recently it was hard to find a bulb that had quality light output as well as the power to adequately light your plants. Now you have a few choices with LED: you can go for “grow” lamps which consist of arrays of red and blue LEDs (the colors plants care about); you can try shop lights, which have very high efficiency but usually iffy color rendering; or you can try to set up track lighting with high efficiency, high quality white LEDs. Because LEDs and track lighting are both very directional, you get a lot of bang for your buck with this solution and save energy costs over the long run. Most LEDs generally have good output in the red and blue parts of the spectrum — good for plant growing and blooming; high-CRI bulbs will certainly cover the whole range. There is considerable talk in the orchid forums that LEDs — at least spot lighting LEDs — require lower actual light output than the EV chart above would suggest. I’d go with the white light solution, because I want to see my orchids blooming in the right colors! One more bonus — LEDs last a Very Long Time.
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High-Intensity Discharge: Commercial growers who need artificial light have long relied on high pressure sodium and metal halide lamps for their lighting. These lamps are expensive and the colors produced by the lights are not natural-looking, but the amount of light they put out is truly impressive. Growers often use them in combination to spur both growth and blooming, and there are rail systems to move the lamps around your space for greater coverage. Too much for me!
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Induction: Induction lamps look a bit like fluorescent lamps, but they’re more efficient and higher output. They’re also hideously expensive.
Wow — that’s an awful lot of stuff about lights…
Getting Serious — Expanding Beyond Two Orchids
My low-light orchids were cool, but once again I wanted variety. After Phalaenopsis and Paphiopedilum the selection of low-light orchids thins out very quickly, so I moved up the scale to Oncidiums (Awn-sid-ee-um) and their relatives.
Orchids are perhaps the largest single family of flowering plants on the planet, with more than 30,000 recognized species and well over 100,000 hybrids. Let’s spend some time on that last word: hybrids. Orchid species interbreed fairly readily within their genus, and often even between related genera. The Oncidium alliance contains a number of orchid genera all living in the Americas, typically producing sprays of delicate flowers; I’ll introduce you to some below. While we’re talking about hybridization, it’s probably good to talk at least a little about orchid growing and naming. Orchids grown for sale are usually clones of a particularly nice parent plant. Hybrids are usually given a name, e.g. Oncidium Sharry Baby. “Sharry Baby” is a hybrid between two specific species or hybrids, but any given plant could come from different parent plants of those species… On the other hand, when a plant is notable, it will gain a cultivar name, e.g. Oncidium Sharry Baby ‘Sweet Fragrance’. Any orchid labeled this way is a clone of that notable ancestor, and should be almost exactly the same in features. You may also see awards after the name, e.g. ‘AM/AOS’ (Award of Merit, American Orchid Society).
Some stores carry the occasional Oncidium alliance orchid — the large King Soopers near me almost always has four or five, and someone in the first diary in this series mentioned Trader Joe’s having them where they lived. (My Trader Joe’s only has moth orchids...) For this diary I am going to concentrate on the “core” Oncidium alliance genera and their inter-genera hybrids. These genera are: Oncidium — the dancing lady orchids; Odontoglossum — known for their spurred lip; Brassia — the spider orchids; Miltonia — known for their large flowers with larger lips; and Cochlioda — known for their unique lip shape. From these core genera have been bred thousands of hybrids. (I’ll cover a few other genera in the alliance in a future blog; as you get further away from the core, the plants and their requirements begin to vary more and more...)
Oncidium Sharry Baby ‘Sweet Fragrance’ AM/AOS: If you’re interested in pleasant smelling orchids, this is the orchid for you! Though the flowers are a relatively plain brown/maroon and white, the fragrance of this orchid is heavenly, smelling strongly of chocolate. If you go looking for one, be sure to get ‘Sweet Fragrance’ and not some other cultivar — the smell on other versions that I’ve seen isn’t as good.
Odonotocidium Catatante ‘Orange Kiss’: This plant has nice orange and yellow flowers a bit larger than a straight Oncidium. I found mine at King Soopers in full bloom; unfortunately, the bloom didn’t last long past the purchase and I have to wait for another growing season to see it again. Odontoglossum orchids — one of the parent genera of the Odcdm. notogenus — tend to like cooler temperatures, but most of the inter-genus hybrids try to breed some of that out so as to fit in better with other common orchid species.
Beallara Tahoma Glacier ‘Green’: Beallara is perhaps the most complex of the Oncidium notogenera, a cross between Brassia, Miltonia, Odontoglossum, and Cochlioda. Like my Odontocidium, I bought this plant at the grocery store in full bloom. It didn’t come with specific instructions, so it’s been in with my other Oncidium plants, but now that I’m researching for this diary I might see if I can find it a cooler microclimate, as half of the parent genera tend to grow in cooler climates.
Aliceara Pacific Nova ‘Okika’: Aliceara is another complex notogenus, whose flowers trend toward a spidery look like their Brassia ancestors. (Brassia orchids are sometimes called spider orchids for their long, thin tepals.) Pacific Nova produces large flowers (the size of moth orchid flowers) in a spike of 6 or more; the ‘Okika’ cultivar was interesting to me because the tepals are a slightly darker yellow.
Family: Oncidium alliance “core”
Aliases: Dancing lady orchid, spider orchid (Brassia), spray orchid
Risk vs. Reward: Medium risk, solid reward. There is so much variety in this broad alliance of genera that you could concentrate just within it and not grow bored. Plants are reasonably readily available and not terribly expensive, and if you treat them right you can get two or even three blooms a season from many of them. The variety of temperature and lighting conditions required by various members of the alliance make growing any specific plant potentially “interesting” unless you understand the genes it has inherited. A number of Oncidium species are high altitude, cool weather plants; this makes them unlike many other orchids, and might require specific placement.
Lighting: Low to high— Some members of this alliance like relatively low lighting (12,000 lx), while some Oncidium species like very bright light (up to 60,000 lx! according to the American Orchid Society). Some knowledge of the plant’s parentage is probably in order when placing an Oncidium alliance plant. If you don’t know the plant’s specific needs, aim for medium to high lighting and let the plant’s leaves tell you; darkening green leaves means more light, very light or purple leaves means less light. Thicker leaves tend to need more light in this family.
Temperature: Cool to Warm— Again, this depends on the species. Those from high altitudes will want cool temperatures going down as low as 50 in the evening, while other species will do poorly unless kept at least 60 or even 65 at night. I keep mine around 60 in the evening, and they all seem to do well.
Watering and Fertilizing: Generally, water thoroughly and let dry between waterings. Plants in these genera with thin roots need more water than those with thick roots. Oncidium alliance orchids have pseudobulbs; if the pseudobulbs on your plant begin to shrivel up (more than they are when you get the plant), the bulbs aren’t getting enough water — either because you’ve rotted the roots, or because you’re not watering them enough. I Fertilize as with moth orchids: 20-10-20 every other week, and a seaweed growth booster once per month.
Potting: Potting in a plastic pot with medium to coarse bark-based mixture is best for most of the alliance species and their hybrids.