Disas By The Seat Of The Pants

First, a bit of instructive history: I have been growing disas, fighting with disas, and trying to bloom disas for about ten years now - a process sharply curtailed by conditions and economy. It has been a mixed bag of results with massive failure the first few years and slow success since. The climate where I live, central Ohio, 43 degreees north, has weather not fit for humans let alone disas. Summers usually run into the mid-90's and winters drop as low as 5 degrees. At first, I attempted to grow the disas outdoors during the summers and indoors in the winters in basement growrooms, along with the rest of my orchids. As you may have guessed, my summer mortality rate was high - but not as high as one would think - about 30%-40%. This is sustainable if the plants which do survive create a normal number of tubers. Unfortunately, this was not the case. In fact, the first two years, all the plants which survived the summer outdoors died soon after being brought in for the winter, a turn of events which utterly mystified me as I thought the indoor season would be the easier of the two. But as I eventually figured out, it was the 'nights' which were the problem.

I use the term 'night' to refer to the period of lights-off. In fact, the lights in the growrooms ran during the solar night, being turned off during the solar day. The temperature gain from the HID lights in the growrooms was such that even with venting if they ran during the solar day the growrooms normally hit 95 degrees and above. By inverting the day/night cycle, and as well, venting in some exterior air while venting the lights out through the furnace cold-air return (which heated the entire house at night without the furnace ever firing up!), I could keep the rooms down to the mid-70's during the lights-on period. The temps naturally dropped in the rooms, which were enclosed against exterior walls, when the lights were off, and the large growroom dropped to between 55 and 60 degrees. The disas were in the small growroom for stronger light but the temps there did not drop below 72 or so. The disas weren't getting what they wanted. Then I started putting them in the small growroom for the light and moving them to the large growroom where I sat them on the concrete floor, for their 'nights'. This brought some limited success and two years in a row I had a disa flower during the winter at Christmas. Don't know why I got these off-season blooms, but I was happy just to see them, though they bloomed so far down in the plant the flowers had a hard time opening properly. Despite these minor milestones, the summers continued to be rough and alas both of those bloomers expired without making tubers. I was especially distraught over one mostly white Diorosa I thought breathtakingly beautiful when it passed without issue. I continued to acquire new plants mostly in the form of flasks I purchased and an occasional gift of a new plantlet from Jim Harper, a generous fellow member of my local orchid society and noted disa grower and breeder. Of course, as I still got virtually no tuber formation, my small stock of plants completely turned over in a period of a year or two. A note about media. My initial medium was a sphagnum/sponge rock mix. I began by growing them sitting in a tray of water frequently refilled. Though this worked well for many folks, it killed most of my first batch of plants and most of my second batch. I stopped growing them sitting in water and moved to keeping them in shallow round trays made by cutting the bottom 4" off a white 5-gallon plastic 'pickle bucket' in which i drilled a 1/4" hole I stoppered with a sharpened pencil. The length of the pencil allowed me to remove and insert it without having to move the plants. A litter box (new) was also pressed into service. A bout of black rot caused me to discontinue this communal watering situation and switch to top-watering.
Speaking of water, I acquired a TDS meter prior to my first disa purchase (Michael Gallagher was adamant in his refusal to sell plants unless a TDs meter was available) and have watered the disas primarily with rainwater throughout, which here tests at 11 ppm. MY tap water which tested out at 460ppm when I first began to grow disas now tests out at right around 200ppm, and I have on occasions of low rainwater reserves, mixed them half and half. I seldom if ever fertilize the disas but when I do I use MI formula at half the strength I use on my other orchids and it tests out about 150ppm. Rainwater is sometimes hard to come by here despite our pervasive cloud cover. Our summers are usually borderline droughts and of course during our winters there are extended periods of freeze where such precipitation as is received is unavailable as it is in solid form.
Then about three years ago, I finally built the greenhouse I had been dreaming of since I was 16. I placed the disas in front of the evap cooler during the warm season, and watered them every few days when they began to be less than wet. I also made a second change. All the plants went into plastic pots, and as an experiment I moved half the disas into diatomite, on the theory it was the medium most similar to their natural habitat of river sand. As well, I had had problems with sphagnum getting slick and foul and I knew the diatomite could be used permanently. The only problem so far with the diatomite was it tends to resettle all the time with top-watering (which can result in plants 'leaning over' and can wash out the top of the pot). During the winter I only heated at night to 55 and days to 60 plus whatever the sun gave (except watering day and the day after when I set the thermostat to 70 during the day), and the disas were pretty happy, and I had another winter bloom. The disas were positioned at floor level in a corner of the GH partially isolated by a 250-gal water tank, and so stayed even cooler than the rest of the GH. As the weather warmed and the GH temp began to rise above 72 during the day, I began to water them at least once a day with the rainwater at about 50-55 degrees to cool the roots down. After the end of May when our 90+degree summer got into full swing, I kept a couple gallons of rainwater in the refrigerator and when the days got to 80 in the GH I watered at least once a day with half refrigerated rainwater/half tank rainwater (two rainwater tanks holding a total of 400 gallons in the summer run about 65-75 degrees) which usually run between 50 and 55 degrees. On especially hot days, I did this twice and when the nights didn't drop to at least 65 in the GH I also did it in the middle of the night with a penlight flashlight held between my teeth (the only good thing ever to come of my sleep disorder is that I'm usually up in the middle of the night).

This treatment produced a first for me: two disas in bloom at the same time; one was in sphagnum/sponge rock and one was in diatomite. I was hoping for some tuber formation; over the previous year a few had expired without tubers but several had made new tubers and several more had 'offshoots'. I was unsure when to repot these as I hadn't gotten this far before. With only a dozen or so pots of disas, 'a few' with tubers was a goodly percentage. June 2010: In 2009 in early May, just prior to leaving for the annual orchid-buying frenzy called the Redlands Orchid Fest, I finally set up the long-awaited flowtable. I had to make arrangements for the disas while I was out of town and couldn't really depend on someone else to water them three times a day (including the middle-of-the-night). The basic set-up is a flowtable tub set atop a used hotdog-cart open-top half-height refrigerator. Inside the refrigerator is a 15-gallon plastic garbage can filled with rainwater chilled to 50-55 degrees. Three times a day the water fills the flowtables for an hour at a time to a little below the top of the medium in the pots. The disas are outside, this year since late February, in 4-inch clay pots (except a flat of small seedlings in 2.25-inch deep plastic pots) in a 3-layer mix I tried out last year. Evaluation of the root systems last fall at repotting time convinced me to put them all in the same mix. The bottom of the pots contain large exploded clay pellets, just enough to keep the next layer, diatomite, from washing out. then the whole is top-dressed with a half-inch of sphagnum as the diatomite had trouble staying moist. I may try eliminating the sphagnum all together this next year as I had to replace it halfway through the growing year as it became slimy and foul despite only having fertilized lightly twice. There is a canopy of cler plexiglass over the entire set-up to keep our often damaging monsoon-like thunderstorms (and kamikaze squirrels, detritus form nearby tall trees, etc.) from damaging the plants, especially the spikes. The plexiglass is covered with a layer of 50% shadecloth. Recently I had to enclose the flowtable in a hardware cloth (wire mesh) cage after the plants were attacked by an animal (probably a squirrel) and I lost three damaged plants.

The refrigerator runs only four hours a day this summer, two before the first flow in the early morning, and two before the second flow at 1PM, after the electricity bill skyrocketed trying to run it 24 hours a day during the summer outdoors last year. This seems sufficient. At repotting time last year, I found robust root systems and much tuber formation and offshoot development. This past winter, the flowtable was set up in the GH in the same floor-level location as previously, without the refrigerator, substituting instead a simple tub-beneath-the-tub water storage chamber, still flowing three times a day. it worked well, I think. I now have 27 individual disas in the 4-inch pots (This represents half the plants I repotted last fall. After repotting, I split the collection in half and gave the other half to a friend for whom I set up a flowtable as well), not all of which are blooming size. Of these 27, 14 are currently in spike. I think the system is working. Next year I plan on trying to give the collection a little direction in terms of flower color and quality, and will have to find homes for the 'extras'.