Basic Information

Last update: 17 August, 2002

The cultivation of orchids in the vivarium alongside Dendrobatid frogs is quite possible. However, certain rules must be followed, and it must be accepted that certain combinations of animals and plants will be impossible to achieve. That said, there are dozens (possibly hundreds) of orchid species that will tolerate both the temperatures and humidity that a Dendrobatid vivarium can generate.

By far the biggest majority of orchids in cultivation are epiphytes. That is to say, they live in nature attached to the branches and trunks of trees, rather than growing in the soil at ground level. This mode of life is quite distinct from them being parasites. They derive no nourishment whatsoever from the trees on which they perch. Their roots are especially adapted as holdfasts rather than feeding organs, and tend to be thick and fleshy, attaching themselves to the bark. Because of the fact that in nature their roots are seldom covered over, the majority of species cannot tolerate wet feet. They must be able to dry out quickly after watering, and must never sit in water. This would surely lead to the death of most species. Instead, they should be suspended or otherwise attached to branches and bark in the vivarium, perhaps by using wires, sprayed with water regularly and then allowed to dry out.

You will need to do some research in order to discover the ideal conditions required by your chosen orchid species. However, as a rough guide, the following is a list of environmental conditions taken from a weather station near San José, Costa Rica, Lat. 10.0N, Long. 84.2W, at an elevation of 3021 ft. (921 m). Temperatures are calculated for an elevation of 4250 ft. (1300 m), resulting in probable extremes of 88°F (31°C) and 45°F (7°C).  Some species of Masdevallia are known to grow here e.g. M. chontalensis.

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX            71      72      75         75      76       75      73      74      75     73       73       71
F AVG MIN              54      54      55         58      58       58      58      57      57     56       56       54
DIURNAL RANGE    17    18      20        17       18       17      15      17      18     17       17       17
RAIN/INCHES         0.6     0.2     0.8       1.8       9.0     9.5      8.3     9.5   12.0   11.8   5.7      1.6
HUMIDITY/%          73      69      68        70        78       83      82      81      84     85     79       76
BLOOM SEASON                        *          *         *         *         *       *        *       *       *
DAYS CLR @  6AM   5     8       11           2         1         0        0        0        2        1        2        3
DAYS CLR @ 12PM   5     4        8            3         0         0        0        0        0        0        0         1
RAIN/MM                 15      5       20          46      229     241     211    241   305    300    145      41
C AVG MAX          21.7   22.2    23.9      23.9    24.4     24.1    22. 8  23.3  23.9   22.8    22.8   21.7 
C AVG MIN            12.2   12.2    12.7      14.4    14.4     14.4     14.4   13.9  13.9   13.3  13.3 12.2
DIURNAL RANGE   9.5  10.0    11.2        9.5    10.0       9.7       8.4     9.4   10.0    9.5    9.5   9.5
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

At this site:
Light is fairly moderate in this particular environment, being in the region of some 800-1500 foot-candles (fc.)  Orchids in this habitat (as in many others) never grow where they are exposed to direct sun. They are more likely to grow in the shade of overhanging branches in filtered or diffused light.  In vivaria, artificial light will most likely be the only light available to these plants, so you must ensure that it is good quality and of a sufficient strength to promote growth and, of course, flowering.  However, having said that, their positions in the tops of tall trees means that they are exposed to strong air movement at all times, and as such this ventilation will be the most difficult factor to achieve within the confines of the vivarium.  A small ventilator fan springs to mind, of the type used for cooling processor units within computers.  This might prove an effective ventilator if it is connected to a time switch to give a regular turn-over of air.

Temperatures – throughout the year, days average 71-76°F (22-24°C), and nights average 54-58°F (12-14°C), with a diurnal range of 15-20°F (8-11°C). There is probably no need to allow the temperature to fall so far at night time in order to achieve good growth. The fact that it does, though, might be worth bearing in mind should you experience problems in otherwise healthy cultivation.

Humidity - at this site humidity is around 80-85% most of the year, dropping to near 70% in winter and early spring. Averages in the cloud forest habitat are probably greater than indicated, however, due to heavy mists and dew.

Water – even though rainfall is heavy from late spring to autumn, averages are dramatically less during winter. Cultivated plants should be watered frequently while actively growing, but water should be reduced somewhat in late autumn. Plants should not be allowed to dry out completely, however. With regard to the type of water used, rainwater is the best. This is essential if you are also attempting to grow some of the carnivorous plants in your vivaria.

Fertiliser – you may choose not to use a fertiliser. Some growers have good results regardless of whether they feed their plants or not. In nature, orchids are adapted to survive on minimal nutrition, and normally survive on only those fragments of plant debris that collect around the roots and the base of the plant. However, for those who would like to experiment within the confines of a vivarium (with frogs, remember, which may or may not tolerate fertilisers) a balanced fertilizer mixed at 1/4-1/2 recommended strength should be applied every 3-4 weeks if plants are grown in sphagnum moss, tree-fern fibre, or Osmunda (see below for these growing media.) If grown in fir bark, the applications should be made every 1-2 weeks. But remember. Use of fertiliser can affect success with other forms of plant life – see below.

Rest period - growing temperatures should be maintained all year. Although rainfall in this example habitat is low in winter, high humidity and the large diurnal temperature range indicate that considerable additional moisture is probably available from heavy dew, fog and mist. Therefore, water should be reduced for cultivated plants, but they should never be allowed to dry out completely. Fertilizer (if used) should also be reduced until water is increased in spring.

Growing media – it has already been stated that orchids are not typical plants, and do not survive if an attempt is made to grow them in houseplant compost or the like. Various substrates can be obtained which may allow the plants to colonise an area of the vivarium. These might include various species of mosses, liverworts, tree trunks and branches, weathered and chipped fir bark in several grades and osmunda fibre. It might also consist of crushed brick, perlite and nut shells from various species of trees. In addition, plants may be mounted on tree fern or cork slabs if humidity is high enough. Several waterings a day may be necessary for mounted plants during very hot, dry periods but these conditions are unlikely to be met with in Dendrobatid husbandry. Charcoal is often added to orchid media to help keep the medium open and prevent it from becoming sour. Propagation can be carried out at any time between autumn and spring that does not interfere with flowering.

A warning: If you are wanting to attempt to grow some of the carnivorous plants in your vivaria (Utricularia – the bladderworts, for example, but Nepenthes spp. being exceptions) then you absolutely must ensure that everything in your vivarium is inert. This must include the gravel base if you are using one and all rockwork. Otherwise the minerals released by such items will have a speedy and terminal effect on your plants. In addition, you must ensure that any water used within the confines of the vivarium is either rainwater or distilled water, and no fertiliser must be used.

The photographs from top: Dendrochillum cabbianum, Barkeria sp., Prosthechea brassavolae, Psygmorchis sp., Stelis sp.