It would seem I have made the same journey that many people make when they build vivariums… starting off with something looking very close to nature, and eventually ending up with something a little more practical. Originally I aimed to recreate a little slice of the cloud forest in my inner city apartment and the result turned out great! Vivarium was fully operational in the beginning of May 2010. Everything was thriving and I was finally growing and blooming all these amazing cool to cold growing species that I had admired for so long. Life was good!

Cool vivarium 1.0

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Problem with EpiWeb

I had chosen EpiWeb for my build, a synthetic medium touted as a good alternative to xaxim. I liked the fact that it was an inert material that would not break down over time and by doing so changing its cultural properties. I also liked that it was light weight and would not get waterlogged. EpiWeb only hold 70% of it own weight in water and does not wick water by capillary action. At first I was really happy with the performance, but soon I would discover one of the main disadvantages with EpiWeb…

The roots would not seek to fill or remain inside the mounting blocks, they would just grow straight through. I want all my mounts to be movable so I can take plants out to photograph them, or perhaps move them if they need a change in culture (a drier rest period for example). But the mounting blocks would constantly get stuck on the back wall since it consisted of the same material as the blocks. The roots would grow hopelessly stuck in the material, the only way to move the mounts would be to rip off the roots. Perhaps I should have foreseen this, but still… I tried a few different solutions in an attempt to tame the roots. Like hot gluing weed barrier cloth to the back of the mounts, later followed by polyethylene dam liner. The weed barrier made the mounts more waterlogged causing mold to grow, while only stopping about 50% of the roots from poking through. The polyethylene liner did the job of stopping the roots, but it also made the environment on the back of the mounts very stuffy. No air would circulate though and there was considerable algae growth and mold forming. So obviously none of these “fixes” would do.

Another serious negative trait of this medium is that it is very hard to cut. You need sharp industrial scissors or a metal saw to do it. So because the medium is not porous like most natural materials like xaxim or cork, you cannot just break apart a mount to divide a plant. There is no way you can gently divide a plant mounted on EpiWeb as the roots would get so entangled in the material and any attempt to divide a plant would lead to massive root damage. The fibres would easily slice through the roots long before breaking. I grow many unusual species and I would very much like to be able to share them with friends in trade, not an easy prospect using this material.

Stelis gelidaEpiWeb blocks for the mounting of orchidsRoot project -hot glue gunRoot project Stelis sp.

Problem with fungus

The final nail in the coffin for me regarding EpiWeb and the natural looking vivarium design however was an outbreak of fungus that struck me late last year. It nearly broke my heart as I lost many plants due to this. I had accidentally turned off the fans in the vivarium (must have come near the button on the timer while cleaning). I was working many late nights at the time I did not realize the mistake for several days. Actually I first noticed the symptoms… leaves turning yellow and spotted, waterlogged sunken spots that rapidly spread through the collection. At first I quarantined the plants affected, but since I water by fine mist from above, the pathogens quickly spread throughout the vivarium, so quarantine was a futile effort.

It can be hard to tell the difference between bacterial and fungal infections, but most bacteria tend to thrive in warmer conditions than what I keep in this vivarium, so most likely I was dealing with some kind of fungi, or perhaps both. I begun treating everything with Physan 20, a broad range disinfectant, fungicide, virucide, and algaecide which is supposed to effectively control a wide variety of pathogens. I cleaned everything in sight then dipped all the plants and sprayed down the EpiWeb walls thoroughly with the Physan 20 solution repeatedly. Most effectively it killed all of the moss in the vivarium along with a few sensitive orchids, but I could not seem to get the fungus infection under control. Part of the problem I believe was that since the walls inside were covered in large sheets of EpiWeb I could not effectively disinfect the growing area. I think this is why the problem kept coming back.

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After a couple of months of battling this I finally got the advice from a friend to try Clearys 3336 F, a systemic fungicide. I decided to do one better. Before using the Clearys I wanted to rebuild the whole vivarium, converting the natural cloud forest into a bit more practical growing space that would be easier to keep disinfected and clean. This meant eliminating as much of the EpiWeb as I could. First I removed all the orchids, next I took down the internal EpiWeb walls och scrubbed the whole vivarium down with soap then sprayed it down thoroughly with Physan 20, making sure I covered everything top to bottom and keeping it wet for 15 minutes so the fungicide could do its thing according to the directions on the bottle.

Next I spent hours upon hours carefully removing all the mounted orchids from the EpiWeb mounts. This was a heartbreaking task as I had to sacrifice a lot of roots in the process, but I was determined to get rid of this awful material once and for all. Well, at least the blocks. I still have EpiWeb substrate in my pots, I have not decided what to do with that yet. It is not as critical to get rid of since the smaller nuggets are easier to divide, but soon I will replace that material as well. Just yesterday I had to release a Dracula bud from the substrate as it was not managing to push through. Once all the mounts were clear I could also assess the damage of the outbreak. It was clear that I had lost about 30 plants in total, and many others reduced as much as 50% in size. Very depressing. But it was nothing to do but to press on. I dipped all the orchids, pot, plant and all for 15 minutes in the Clearys solution, followed by all the bare root plants. This was an all day operation.

New design

Next I turned my attention to the reconstruction of the vivarium. I built an aluminium rack for hanging pots from, five rows with 14 pots per row, staggered so the water from the row above would not drain into the row below. I wanted to have plenty of air around the plants too so there would be less risk of more problems with fungus. For the mounts I made plastic mesh panels for the back and side walls. I attached it to some aluminium rods for weight and stability, then mounted them to the walls using the same holes I had previously hung the EpiWeb with. Simple and clean solution.

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As one more insurance policy for this I also designed a “rain proof” box fan for the bottom of the vivarium. A rectangular PCV pipe with four holes cut in it and two computer fans mounted inside. Then a louvered plate to cover each hole, louvers pointing up in the front pushing the air up, louvers pointing down in the back so the fans won’t suck in so much moisture. I left the ends open to allow for more airflow and also so water won’t collect inside, drilling a weep hole under each fan too just in case. The idea is to keep the air on the bottom and behind the rows of pots from getting stagnant. Works quite well actually. The added air circulation, new design and the fact that I will now be able to spray the hard surfaces in the vivarium down with Physan 20 at regular intervals as maintenance should keep troubles at bay.

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Finally, it was time to mount the some 200+ mini orchids again. I tested the water retention capacity of two different types of xaxim, hard (Dicksonia – left in the photo) and soft (Cyathea – right in the photo). But I think both kinds hold a little too much water for my liking. While dry the hard kind weighed 44 g and the soft kind 26 g. After soaking the blocks for an hour in water the hard kind weighed 70 g and the soft kind 110 g, so that pretty much said it all. The soft took three times longer to dry out as well… so if I was going to use xaxim, it would definitely be the hard kind, but it is a little difficult to get a hold of so I settled on cork instead. They say you should actually support the cork industry now that much of the wine industry has switched to synthetic. I found some all natural, heat pressed sheets online and made my mounting blocks out of that then using fishing line to tie the orchids to the cork.

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Many, many hours later, the minis were mounted and all the orchids back in the vivarium again. A few weeks have passed and I have sprayed all the plants thoroughly with Clearys twice more with one week in between. Everything looks good now and I think catastrophe is finally is averted. Thank goodness. All in all the plants were actually in better condition than I had originally thought, and after the radical treatment the survivors are looking very good across the board. I lost a few more plants to the treatment though, but not as many as I had feared. Although I am mourning a beautiful little Masdevallia that was lost…  Some flowers were lost too, but most buds faired well and several plants are now blooming again which raises the spirit too.

Cool vivarium 2.0

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This experience has been heartbreaking and very depressing, but I am not defeated, just a painful experience richer. The vivarium looks dramatically different now, but it works beautifully, more like a greenhouse. I kind of like it… at least I do not miss the old design with all the EpiWeb headaches. I am very pleased with this new setup and the orchids are already making a strong recovery.