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CP Companion plant: Disa orchids-grow guide and photos, 2013

Posted: Mon Jul 22, 2013 8:24 pm
by meizzwang
For those of you who aren't very familiar with Disas, they are cool growing terrestrial orchids that prefer conditions similar to heliamphora/cephalotus/darlingtonia. In their native South African home, they grow on the sides of streams, often times in pure live sphagnum. Disa uniflora is the main species grown because the flowers are gigantic, and some can last up to 2 months if kept cool! I've had some hybrids produce 6 gigantic flowers on one spike! If you have a good sense of smell, they have a very faint,chocolate-like fragrance that is strongest during the day. The blooming period is during the summer (in the northern hemisphere, they bloom between early June thru early August).

Because of their similar growing requirements, Disas are easily integrated into Carnivorous plant collections. There doesn't seem to be much information online on how to grow these, and I definitely have some info that can't be found elsewhere, so I'd like to share some of my experiences. Below is a general outline on how to grow these amazing orchids:
TEMPERATURE
Keep the soil temperature below 85F (29C). Frost sensitive-leaves will burn if below 31F (-0.5C). VERY light frost is okay, but not ideal. During the winter "dormancy" period, if you live in an area with deep freezes and you don't have a greenhouse, they can be kept temporarily in a garage or unheated room until the threat of frost passes. Optimum day temperature is 75F (24C) with night temperatures around 55F (13C). During the summer, our temperatures in California are 80-90F (27-32C), but since these are grown with afternoon filtered light, they stay cooler. I've had day temperatures in the 100's with no ill effect: the key is to keep them in pure shade during the heat waves. Cool nights are also key to growing these plants. I grew these in Sacramento, CA where we had 110+F temps for 2 weeks straight! They surivived because the temperatures dropped to 65F (18C) at night.

SOIL
I use 80% long fibered sphagnum, 20% perlite. Some people use peat and sand, or peat/perlite with great results, but for whatever reason, I've never succeeded without using long fibered sphagnum.

LIGHT
Ideal conditions outdoors are morning sunlight and afternoon filtered light/shade. In a grenhouse, bright, indirect light all day is ideal. If the leaves turn purple, there's a good chance they are in too much light. They grow surprisingly well in lower light levels.

WATER
Use De-ionized, Reverse Osmosis, or water low in total dissolved salts. They require water similar to carnivorous plants (in fact, these grow with Drosera capensis in the wild!) I have them sitting in trays, and they get overhead watering every day. The trays temporarily fill with a little bit of water, but by the end of the day, all the water evaporates away. They can sit in a little bit of water, but I prefer to not have them waterlogged since such conditions invites bacterial and fungal diseases.

FERTILIZER:
Fertilizer is very important:use an acidic orchid fertilizer. Use 1/4 strength approx. once a month, if not more frequently. Fertilize in the fall once new stolons/tubers begin to produce new leaves, but stop during the beginning of winter or when you notice growth slowing down. Start fertilizing again once you see growth resuming in late winter/early spring. Stop again in late spring/early summer or once you have a flower spike formed, or the plant has stopped growing. The concept is fertilize only when the plant is actively producing leaves or is forming a spike.
TRANSPLANTING
From my experience, it seems the best time to transplant is early fall and late winter/early spring. After your plants flower in the summer, the entire collection will look like it has "crashed." This is normal. If there were stolons/tubers formed underground, you'll get a ton of plantlets crowding the pot. Ideally, when you see new growth emerging from underground tubers, and they have 3-4 leaves, it's a good time to repot. They should be repotted every 2 years or so: they LOVE new media, and HATE old, decomposed media. Be very carful not to damage the roots or break off the tubers. Do not underpot or overpot the plant.




And now the photos! These were taken July 2013. And I wasn't kidding when I said these make great CP companion plants-note the cephalotus and S. jonesii in the foreground:

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Another overview shot:
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The large flowered clone in the picture below is D. 60.1 'RED' It's one of the later blooming clones (which helps extend the flowering period), and it consistently produces magnificent blooms year after year. The pink one in the background is the named cultivar, D. Louis Vogelpoel 'Candy':
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Can't remember which one this is:
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This is D. 206 'orange':
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Re: CP Companion plant: Disa orchids-grow guide and photos,

Posted: Mon Jul 22, 2013 8:28 pm
by parker679
Thanks Mike, those are some really beautiful orchids.

Re: CP Companion plant: Disa orchids-grow guide and photos,

Posted: Mon Jul 22, 2013 8:33 pm
by meizzwang
You're welcome, and thank you!

Re: CP Companion plant: Disa orchids-grow guide and photos,

Posted: Mon Jul 22, 2013 8:42 pm
by Matt
Thanks so much for posting this Mike!

Re: CP Companion plant: Disa orchids-grow guide and photos,

Posted: Mon Jul 22, 2013 8:51 pm
by meizzwang
anytime Matt :)