La Asamblea General de Participantes de los Fondos de Inversión

Before even beginning a discussion of the cultural requirements of catasetums, we must understand the climatic and ecological conditions to which these plants have become accustomed over the eons of time in the various parts of their natural range. In fact, a major thrust of the present volume lies in this unique knowledge, which now makes it possible to discontinue lumping all catasetums under one cultural blanket.

Several generalizations can be made about Catasetum habitats: they are definitely not found in forests dark and dreary, and they always occur in regions with distinct rainy and dry seasons, although these may be short or very long. Another truism is that whenever you see palm trees, especially along a riverbank, suspect that catasetums are growing half-hidden beneath the leafy palm fronds.

I have divided the Catasetum world into five climatic or ecological zones. Each zone has environmental conditions that are translatable into distinct artificial cultural requirements. These zones are named after five colors, as shown in Plate 90.

The climatic or ecological zone in which a Catasetum species originates affects especially its growth cycle, light exposure, and temperature and humidity requirements. Catasetums from the Gold and Gray Zones can adapt readily to the Red and Green Zones, but not vice versa. Since plants from the Gold and Gray Zones generally will be grown in the greenhouse under typical Red or Green Zone conditions, the description of the rather austere habitat conditions given below is primarily for background information and to shed some light on the ability of species from those zones to withstand harsh treatment during emergencies. Furthermore, it should be clearly understood that a Catasetum species assigned to a specific climatic zone may also occur in microclimates in other zones.

More detailed information on these climatic zones can be found in Pabst and Dungs (1975, 1: 3543). I have made a slight change in the colors used in that work to represent the various zones, and have modified the scope of the map, but the basic information still applies to catasetums and other orchids.

Red Zone

The climate in this zone is evenly hot, moist, and tropical. It is typical of coastal lowlands and the vast Amazon River basin. This climate is almost the same year-round, with high

humidity at night, even in the dry season, which is relatively short. Temperatures range from a maximum 86°F (30°C) to a minimum 59°F (15°C).

From mid-Mexico southward, the Red Zone hugs the hot, humid coast on the Gulf of Mexico side, interrupted by the dry northern half of the Yucatan Peninsula. From the southern half of that peninsula southward, it includes all coastal Belize, then continues through the narrow littoral of Honduras, the broad Atlantic coastal lowland of Nicaragua, the coastal jungles of Costa Rica with rainfall nearly year-round, and Panama, where the rainy season lasts from mid- May to mid-December. The Red Zone ends at the Colombian border, but resumes on the Venezuelan coast and then extends into most of the Amazon basin and far into south-central Brazil. The Brazilian coastal strip from Pernambuco State southward is also part of the Red Zone.

A large portion of the species for which I have given detailed descriptions originate in this Red Zone: Catasetum albovirens, C. arietinum (also found in the Gray Zone) C. ariquemense, C. barbatum, C. bicolol, C. callosum, C. complanatum, C. confusum, C. cristatum, C. denticalatum, C. discolor, C fimbriatum (also found in the Gold Zone), C. galeritum (also found in the Gold and Gray Zones), C. gardneri, C. garnettianum, C. gnomus, C. imperiale, C. integerrimum, C. kleberianum, C. laminatum, C. lanceatum, C. longifolium, C. longipes, C. macrocarpum (also found in the Gray Zone), C. macroglossum, C. maculatum, C. microglossum, C. moorei, C. multifidum, C. napoense, C. ochraceum, C. parguazense, C. pileatum, C. planiceps, C. rivularium, C. rolfeanum, C. saccatum, C. semicirculamm, C. tabulare, C. tigrinum, and C. viridiflavum. Taking a cue from the description of climatic conditions in this Red Zone, growers of these species will give their plants all the warmth and moisture they can tolerate during their active growth cycle, which often lasts much of the year.

Green Zone

The climate in this zone is subtropical. The terrain is hilly, with hot, humid air collecting at the base of the hills, then rising and condensing into mist or rain usually late in the day. The forest becomes saturated, with low temperatures at night, but in the morning the sun's rays and drier breezes promote evaporation. The dry season in winter is short, and nighttime humidity is high throughout the year. Temperatures range from a maximum 86°F (30°C) to a minimum 50°F (10°C).

The Green Zone in Central America occupies a strip inland of the dry Pacific coastal belt. Away from the coast, it passes through a region of increasing altitude, from about 650 to 4900 ft. (200 to 1500 m), that draws moisture from the clouds. On the Pacific (western) side of South America, the Green Zone features moderate elevations on the eastern slopes of the Andes. On

Brazil's east coast, it covers hillsides overlooking the Atlantic tropical coastal lowlands, in addition to a couple of pockets in the inland portion of northeastern Brazil.

Green Zone Catasetum species include C. atratum, C. cernuum, C. incurvum, C. luridum, C. rodigasianum, C. tenebrosum, C. triodon, and C. trulla. Since high humidity and somewhat cooler temperatures typify the Green Zone, growers of these species will want to treat their plants accordingly. Green Zone catasetums do not appreciate Red Zone heat, which can even be oppressive to humans.

Gold Zone

The climate in this zone is essentially continental. The dry season is long and the humidity is very low throughout much of the year. Days are hot and dry, while nights are fairly cool. The terrain is typically tropical to subtropical savannah country, with the surface soil shallow and incapable of sustaining large trees. This gently rolling terrain is characteristic of Brazil's Central Plateau, with elevations of 1650 to 3300 ft. (500 to 1000 m). Temperatures in the Gold Zone fluctuate more than in any other zone and range from a maximum 102°F (40°C) to a minimum 50°F (10°C.).

The Gold Zone is exclusively Brazilian, covering parts of the states of Maranhão, Piaui, Bahia, Goiás, Mato Grosso, and Mato Grosso do Sul.

Gold Zone Catasetum species include C. appendiculatum, C. aripuanense, C. fimbriatum (also found in the Red Zone) C. fuchsii, C. galeritum (also found in the Red and Gray Zones), C. juruenense, C. osculatum, C. pulchrum, C. rooseveltianum, C. schmidtianum, C. spitzii, and C. vinaceum. Growers of these species should bear in mind that the plants are accustomed to, and can if necessary withstand, greater temperature extremes than those from the other zones.

Gray Zone

The Gray Zone is much like the Gold Zone, but more so. The climate is tropical to subtropical, with dry, near desertlike conditions, even along the Pacific coast. It has an even longer dry season and low humidity almost year-round. Most of the moisture results from nighttime dews. In this zone catasetums are found mainly in gallery forests and isolated palm groves. Temperatures range from a maximum 102°F (40°C) to a minimum 59°F (15°C.).

The Gray Zone includes a narrow strip along the entire Pacific coast of South and Central America, northward into Mexico. It also includes large areas in the eastern, northern, and south- central portions of South America.

Gray Zone Catasetum species include C. arietinum (also found in the Red Zone), C. carolinianum, C. expansum, C. galeritum (also found in the Red and Gold Zones), C. hookeri, C. macrocarpum (also found in the Red Zone), C. naso, C. pendulum, C. punctatum, C. purum, C.

sanguineum, and C. uncatum. Growers of these species will not want to try to reproduce the dry conditions prevailing in the Gray Zone for much of the year, for as stated previously, most plants of this group will readily adapt to, and even thrive under, much moister conditions.

Blue Zone

The Blue Zone consists of land that is mostly too high for catasetums. On this elevated terrain the temperatures are more nearly constant and the humidity is quite elevated. Only one Catasetum species is found in this forbidding (for catasetums) zone, C. costatum. Temperatures range from a maximum 86°F (30°C) to a minimum 50°F (10°C).

Figure 5-1. Palm tree hosting a Gold Zone Catasetum with seed capsules. Photo by Fred Paget.

Figure 5-2. Seedlings of Catasetum fimbriatum, a Red Zone species that invades the Gold Zone, in a tree called ipê-amarelo in Brazil.

After reading about and assimilating the climatic and ecological conditions under which catasetums grow in the wild, would-be growers of these orchids are ready for the next step, namely, simulating nature and creating artificial conditions under which the plants will not just survive but really thrive. I can say from personal experience that extrapolating from the natural to the artificial is the key to success. More than 20 years have passed since I succumbed to the bite of the orchid bug. I have gone through four greenhouses, all the while becoming increasingly convinced that enlightened greenhouse culture comes the closest to providing optimal conditions for growing orchids, at least for those of us who do not live in tropical or subtropical climates. The physical plant in which our orchids are grown is the cornerstone, and considerations such as mounts, pots, substrate, and the like are subsequent refinements as we build upon the basic structure.

I attached my present greenhouse to my newly built house in the Shenandoah Valley of Virginia on a slightly down-sloping hillside, facing south-southeastward, exposed to full sunlight. In fact, the practically treeless house lot was selected specifically with a view to the positioning of the greenhouse. I strongly believe that the grower should begin with maximum sunlight, and then reduce it as desired, rather than vice versa. Furthermore, all greenhouse facilities and arrangements should be the result of thoughtful, careful planning, based either on the grower's personal experience, the best recommendations of the experts, or a combination thereof. The facilities should, of course, be tailored to the specific plant-growing lifestyle of the grower and preferences as to types of plants. Growing preferences change with time, so planning should allow as much as possible for potential future interests, expansion, and the like. Granted, all greenhouse solutions are a compromise, since some otherwise desirable features are mutually exclusive, but I was determined to combine the best features of previous structures, while eliminating arrangements that had disappointed (an overhead misting system, for example). All that glitters is not gold!

My greenhouse is an acrylic/fiberglass structure 18 ft. (5 m) wide and extending 32 ft. (10 m) out from the house (Figure 5-3). The 24-in. (60-cm) foundation consists of concrete block veneered with brick matching that of the house. Consistent with a conviction that interior height is conducive to good orchid growing, the arch peaks at about 11 ft. (3.4 m).

Figure 5-3. Author's greenhouse in winter.

The bench arrangement remedies a pet peeve: greenhouses that have excessively narrow aisles that constantly force a visitor to duck and wend past rampantly growing plants. After building temporary wooden benches as a stopgap, I decided, for a permanent arrangement, to lay concrete blocks to support 5-ft. (1.5-m) lengths of 1 1/4-in. (3-cm) metal conduit, which in turn sustain tiered shelves consisting of 1 × 2 in. (2.5 × 5 cm) mesh welded galvanized fencing. The concrete block supports are painted with cement paste for aesthetic considerations. The fencing is sufficiently rigid when adequately supported and provides an environment similar to that of hanging pots. It permits virtually unrestricted air circulation, blocks very little light, and offers little surface for harboring insect pests. Some growers object to shelves one above another, believing that plants on the lower level receive excessive water and insufficient light. I turn those very objections to advantage by placing shade- and moisture-loving plants on the lower shelves and also using them as a temporary home for catasetums about to spike when male flowers are desired. Concrete walkways laid on a 4-in. (10-cm) layer of gravel spread over the entire floor are of ample width for effortless walking. The overhead space is fully utilized by a system of 3/4-in. (2-cm) metal conduit from which light-loving specimens, plants with pendent flower spikes, and those with long aerial roots, are suspended. At the house end of the greenhouse I reserve 7-ft. (2.1-m) high shelves for dormant conventionally potted catasetums where they receive only enough water to prevent their pseudobulbs from shriveling and their root systems from dying.

Winter heat is provided by a thermostatically controlled propane-fired water heater (inside the basement wall of the house) that circulates hot water through finned copper tubing around the perimeter of the greenhouse. I increased the footage of tubing in the house end to create a warmer zone for catasetums and other warm-growing plants, while progressively cooler temperatures prevail toward the far end of the structure. I strive for night temperatures in winter no lower than 65°F (18°C) in the warm end, 60°F (15°C) in the intermediate zone, and 55°F (13°C) in the cool end. On sunny winter days, no matter how low the outside temperature, the greenhouse level normally rises to 7084°F (2129°C).

For summer cooling, I built a 10 × 2 ft. (3 × 0.6 m) section of cool cell pads into the foundation of the far end of the greenhouse. The pads are saturated with cistern water by a submersible pump that functions while the first of two individually thermostated exhaust fans at the house end of the greenhouse is operating. Summer temperatures in the warm end, where most of my catasetums reside, usually reach 85°F (30°C) on warm, sunny days. I cover the ''sunny" (southwestern) side of the greenhouse with 50-percent shade fabric during late spring and summer, for the sunlight can be very bright indeed in such an exposed situation. I use no shade fabric on the eastern side, for mornings are frequently cloudy.

During the cold season a blower-inflated polyethylene bubble covers the entire greenhouse to facilitate maintaining warm conditions inside.

I water my plants with rainwater collected from the house roof and stored in a 1000- gallon (3785-liter) cistern buried in the hillside below. The water is pumped from the cistern by a jet pump into a pressure tank and then into 50 ft. (15 m) of 3-in. (8-cm) PVC pipe suspended under the perimeter benches on one side of the greenhouse. Storage in the PVC pipe brings the cold cistern water to greenhouse temperature so as to avoid shock to warm-growing plants. I use a simple proportioner for fertilizing. I check the pH of the cistern water frequently and acidify it as needed to ensure a slightly acid condition. Periodic checks of the water for electrical conductivity reveal, on the average, 57 ppm (parts per million) of dissolved solids, which I consider highly acceptable. My well water is hard and forms calcium deposits on the leaves of the plants, so I use it only to wet down under-bench space to increase humidity.

Since air movement is extremely important, three ceiling fans are spaced evenly through the greenhouse, and they run continuously. Six muffin fans cover the dead space.

I am able to maintain 65 to 75 percent humidity by plant watering, wetting down walkways and under-bench space, and cool-cell operation in the summertime. Several times I have considered adding a fogging system, but have so far resisted the temptation.

I find that my greenhouse setup offers many options for creating microclimates of light, water, temperature, and air movement, in an attempt to extrapolate growing conditions observed in the plants' habitats to my greenhouse culture.

Besides my catasetums, which increasingly represent the showpiece of my orchid- growing effort, I also grow cattleyas and laelias (species only), Madagascan angraecoids, stanhopeas, gongoras, cyrtopodiums, lycastes, and botanicals. I am proud to be able to say that I grow in my greenhouse almost every one of the Catasetum species given detailed coverage in this book.

Chapter 6