A Do-it-yourself Wardian Case

by Prem Subrahmanyam

Those of us growing orchids in warmer climates often find ourselves envious of the beautiful orchids and delightful miniatures that can be grown just outside of our temperature range.  We either have the choice of trying to keep such plants barely surviving out in the heat and humidity that is northern Florida, or trying to grow orchids inside in our cooler but drier air-conditioned homes.  There is, however, a third choice, and that is growing orchids in a Wardian case.  This can allow us to more optimally adjust both the temperature and humidity.  While there are many very nice, but extremely expensive, pre-built units available on the market, it is possible to design a useful unit with a small investment in materials and a bit of ingenuity. This article will present a low-cost set-up used to grow a variety of intermediate-to-warm orchids in the Tallahassee, Florida area.

Basic Wardian Case Design

When designing your Wardian Case, there are four main points to consider:

Light: The amount of light needed depends on what kinds of orchids you plan to grow.  A number of lower-light orchids, such as Masdevallia, Pleurothallis, Restrepia, some Angraecum, etc. would probably do fine under a small bank of 24" under-cabinet 20 watt fluorescent lights.  For medium-to-high light orchids such as Cattleya, Oncidium, smaller vanda alliance orchids, and the like, biaxial fluorescent lights from an aquarium supplier might be in order.  You could also purchase a pre-built aquarium hood, but be sure it is one with lights in front and rear, for more even light placement, and one with the lights separated from the inside of the tank with a sheet of lucite.  This is important to keep temperatures down, as ballasts from even the smallest of lights can generate quite a bit of heat.  In addition, an open air space between the lights and the lucite can allow air to circulate through and carry the heat away from the interior of the case.

Finally, the placement of either mirrors, mylar coated foam core sheets, or even a white diffuse surface (such as the shelf liner used in this particular Wardian Case) can help in light recovery, reflecting light back into the tank for the plants to use as opposed to allowing it to escape out of the sides.  Mirrors can also make the inside of the Wardian Case seem more spacious as well as allow viewing of portions of the inside of the tank not easily visible from the front.

Temperature: As anyone who’s stubbornly tried to grow a coolish growing Miltoniopsis or Masdevallia in Florida conditions, not all orchids are suited for our climate.  Many have strict temperature requirements for optimal growth, and unless those requirements are met, an orchid could grow poorly, bloom poorly, or just plain die.  Pridgeon’s Illustrated Encyclopedia of Orchids lists the following broad temperature ranges for orchids:

For most of us in Florida, cool side of intermediate is probably about as cool as we can grow orchids here, without some special amendments made to an Wardian Case. Placement near an air conditioner vent or a window that can be opened at night can help keep temperatures cooler as well.

Humidity:  in general, because an Wardian Case is an enclosed space, humidity tends to run high on its own…in fact, when designing an Wardian Case, be sure to include a means to vent in air from the house to bring humidity levels down a little when necessary.  Optimal humidity targets are 70 to 90 percent.

Air Movement:  in designing an Wardian Case, this is a very critical element.  Circulating air helps to dry out overly-wet media after watering, and dry off foliage and flowers before pathogens can invade plant tissue.  If the air inside your Wardian Case is too still, you will likely lose plants rapidly to rots.  Placement of one or more fans inside an Wardian Case can ensure good air circulation.  And by blowing the air over something like a tabletop “zen fountain”, you can help raise humidity and lower temperatures through evaporative cooling.  In addition, with adequate air movement, use of clay pots along with a water retentive medium can extend the range of feasibility for cooler-growing plants by a few degrees lower, even if the air temp in your tank might be a few degrees too warm.

Construction/Materials Specifics

The following materials were used to design this Wardian Case:

Total Materials Cost: $176

The hood is constructed out of a frame of 1 x 2's surrounding a sheet of lucite cut to the dimensions of the tank.  Two supports hold a piece of plywood to which I have the light units screwed on (I eventually plan to replace them with biaxial fluorescents used for aquarium lighting).  It is put together with screws for easy construction/deconstruction/reconstruction.  A small hole cut into the lucite in one corner allows the cords from the fan and fountain into the tank.

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Figure 1 - Hood Construction

The tank itself is lined with semi-adhesive shelf liner cloth with decorative text saying "Orchid Delirium".

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Figure 2 - View of Entire Wardian Case

Note how the plants are placed on staggered shelving (or hung from the sides of the tank) that allows for free drainage into the bottom of the tank (which can be cleaned periodically with a towel if need be).  The fan is a 6" clip-on fan held in place by a twisted length of galvanized wire that is bent over the side of the tank.  This is set to partially blow over the "zen" fountain and partially into the main part of the tank.  Instead of using a 6" fan, "muffin fans" used for computer power supplies can be purchased for a reasonable price and wired to an AC/DC adapter of the appropriate voltage.

Plants grown in the Wardian Case

The following plants are being grown successfully in this Wardian Case (note, some of these may not appear in these photographs):

Plants that are highlighted above have a link to their own mini-gallery.

Here are some closer views of some of the plants growing in their mini-habitat:

First a shot from the left end of the Wardian Case.  In the foreground are a compot of an undisclosed Phal. hybrid, a large (yet unbloomed) Paph. Gloria Naugle, a bare pot housing a dormant Pecteilis sagarikii and a Paph. armeniacum.  Behind the Gloria Naugle are Masdevallia floribunda, Stelis triangulisepala and the Scaphosepalum microdactylum.  On the upper level are Ionopsis utricularoides, Angraecum magdalenae, Angraecum distichum, Epidendrum seedling compots of undisclosed parentage, Pleurothallis restrepioides, Restrepiella ophiocephala, Dyakia hendersoniana and Pleurothallis brighamii.  Hanging from the back and side, left to right, are a Pleurothallis sp., Dendrophylax (Polyrrhiza) lindenii, Haraella retrocalla, Chiloschista usneoides, Restrepia antennifera, Dendrobium leonis, and Pleurothallis sicaria.

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Figure 3 - view from left end of Wardian Case

Second, a shot from the right end of the tank, looking left.  In the foreground are the Restrepia striata and Pleurothallis brighamii.  Behind the brighamii is Dyakia hendersoniana, just starting to spike (April 2002).  To the right and going back along the tank are the Chiloschista, Haraella, Pleurothallis sp. and the Angraecum magdalenae in the extreme right background.

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Figure 4 - view from right end of Wardian Case

Third, a closeup of the blooming Dyakia hendersoniana:

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Figure 5 - blooming Dyakia hendersoniana

Fourth, a closeup of a happy Scaphosepalum microdactylum:

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Figure 6 - blooming Scaphosepalum microdactylum

Fifth, a shot of four happy bloomers/spikers, Pleurothallis brighamii blooming like mad in the foreground, Haraella retrocalla in bud to the left, Chiloschista usneoides finishing its flowering to the right background, and a bud from the Restrepia antennifera just in front of and to the right of the Chiloschista.

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Figure 7 - happy bloomers/spikers

Copyright © 2002, Prem Subrahmanyam, All Rights Reserved.

Further reading

Kaya Eschete's Dracularium
Aquarium Hobbyist Supply - a source for high-powered aquarium lighting