General Overview:
The Catasetum orchid is a splendid, brightly colored orchid species, prized by growers for its versatility and beauty. This orchid is relatively easy to grow if you can create the right conditions. Almost always deciduous, the pseudobulbous plants have strict growth and dormancy periods that alternate each year.
These vibrant plants are native to Argentina, Brazil, Mexico, South America, and Central America, where they can grow in sandy, rocky environments and near ant colonies. This orchid produces fleshy, waxy flowers, and the plants are unisex, a rare occurrence among orchids. Male plants are recognizable by their bright colors and large size, while female plants are yellow-green and smaller. Another distinguishing feature of this species is its ability to expel pollen directly onto pollinators. This care guide applies to all Catasetum, Cycnodes, and Clowesetum.
Growth cycle:
Understanding the growth cycle of Catasetinae is key to a successful cultivation. When plants are actively growing, maintain a fairly constant root zone moisture level and fertilize regularly to optimize new growth. When plants are dormant, little or no water is needed, as the pseudobulbs store enough water and nutrients to survive the winter dormancy.
Start of season:
Catasetums begin their new growth cycle between winter and early spring. As soon as you see new growth, repot your plants in fresh soil. Last year's roots appear to deteriorate during dormancy and aren't as efficient at absorbing water and nutrients as new roots. Whether you repot or not, don't water the plant until the new growth has developed roots. New roots should be 8 to 12 cm long, so for simplicity's sake, hold off on watering until the top growth has reached 8 to 12 cm. Don't water until the new growth is well established.
Mid-season: The new roots have established themselves, and the plants are rapidly developing their new pseudobulbs. The sudden growth during this 3-4 month period is striking: plants often double in size. To keep up with their growth rate, plants require constant moisture and regular fertilization. Typically, they are watered 2 or 3 times a week. A balanced, full-strength fertilizer is suitable for this rapid growth, or you can top-dress with a controlled-release fertilizer and apply water-soluble fertilizers at a diluted rate, such as 2 grams per liter. Light levels at or above those recommended for Cattleyas will help ensure vigorous growth and lush flowering. The fruits of your labor will begin to bear fruit at the beginning of the flowering season.
End of season: In late fall, plants will begin to enter dormancy, caused by the maturation of the pseudobulb, shorter day length, cooler day/night temperatures, and reduced root zone humidity. The first signs you'll observe on your plants are yellowing and browning of the leaves. As a general rule, this will occur by mid-November, at which point you should stop fertilizing and reduce watering by half. Once all the leaves have fallen or by the end of December, stop watering your plants. Watering during dormancy should only be done if the plants' bulbs are severely wilted. A single watering is usually sufficient to regenerate the bulbs.
Light requirements:
Catasetum orchids are sun-loving plants, and in their natural habitats, many species thrive in full sun. Unless the strong air movement typical of their natural habitat is available, the grower should also provide some shade. For lush spring growth, Catasetum plants should be positioned to receive as much sunlight as they can tolerate, depending on their origin. However, as their pseudobulbs mature, it's important to consider whether you want male or female flowers.
Catasetums are known to produce male or female flowers depending on the amount of light and humidity they are exposed to. High light and low humidity tend to induce the production of female flowers, while low light and high humidity produce male flowers.
Temperature requirements:
These orchids are native to warm tropical areas and grow during the rainy summer months. During this growing season, daytime temperatures between 27 and 38°C (80 and 100°F) and nighttime temperatures between 16 and 18°C (61 and 64°F) are beneficial. After maturation, nighttime temperatures can be reduced to 12°C (54°F), with daytime temperatures ranging from 21 to 30°C (70 to 86°F). In general, for all but a few species, the grower can consider 18°C (64°F) as the ideal minimum nighttime temperature and need not worry excessively about daytime highs, as long as they remain below 39°C (102°F).
Water requirements:
Catasetums require abundant water during their growth phase. This begins when new shoots appear with the onset of pre-monsoon rains. Watering should be gradually increased as they mature, towards the end of the monsoon. Once the pseudobulbs are mature, watering should be reduced and thinned out until they begin to lose their leaves, which indicates that watering should be stopped completely, except occasionally, to prevent the pseudobulbs from shrinking. It is at this time that they will begin to flower.
All Catasetums grown in pots, baskets, and non-conventional pots can be watered every sunny day during the growing season, provided that conditions allow them to dry out relatively quickly. For mature plants grown in conventional pots, watering should not be necessary more than once or, at most, twice a week. These species tend to dry out at least slightly between waterings. When watering, do so generously, allowing the water to drain freely from the bottom of the pot after saturating the entire contents or penetrating the entire root mass of potted and basket-grown plants.
Humidity requirements:
The Catasetum orchid tolerates a relative humidity of 40-60% during the growing season, but 70% is recommended for optimal development of new shoots and flowering. This humidity can be achieved indoors by placing the plants on gravel trays, only partially filled with water so that they don't remain submerged. Air should be constantly moving around the plants to prevent fungal or bacterial diseases, especially in high humidity or cold temperatures. Higher humidity increases the plants' ability to withstand and benefit from their share of light and also slows the evaporation of moisture from the soil in which they grow. Higher humidity also reduces the likelihood of red spider mite infestations, as these small creatures prefer warm, dry conditions.
Fertilizer Requirements:
Catasetum orchids have a reputation for being picky during active growth, and the concept of intensive fertilization should apply to both fertilizer concentration and frequency. The primary goal should be to push the plants to their limits, making them as strong, healthy, and vibrant as possible. Fertilize with an appropriate formulation at least weekly during the growing season, or use a weak formula every time the plants are watered. Use a high-nitrogen formulation (such as 30-10-10) with a full range of trace elements during active growth, gradually reducing the amount as pseudobulbs develop. When the leaves begin to unfold, and well before flowering, add a high-phosphorus formulation to develop large, robust pseudobulbs capable of producing robust inflorescences. Any soluble product with a high double-digit N:P:K ratio is a good source of phosphorus. In autumn, with the exception of plants that normally flower in spring, a formulation that promotes flowering should be used.
Recommended fertilizers:
- Balanced fertilizer for growth: 20-20-20 (NPK) – 2 grams per liter of water – Spray once every two weeks (14 days) – Mid-season only
- High phosphorus fertilizer for flowering: 0-52-34 (MPK) – 1 gram per liter of water – Spray every two weeks (14 days) – Late in shoulder season
Repotting, substrates and propagation:
Repotting should be timed to coincide with the start of new growth, usually in spring. During this time, new roots will form rapidly and the plants will experience minimal shrinkage. These plants have vigorous root systems and require rich, moist soil, such as coconut chips, during the growing season. Many growers bring bare-root plants into the pot during their dormant period to ensure dry conditions during this time. Fine-grained substrates are common for smaller pots; medium-grained substrates are used only in larger pots. Sphagnum moss is used successfully in many areas, as it offers tremendous water and fertilizer retention capacity.
Once fully grown, these orchids can be divided into a mature pseudobulb, which will flower on the next mature shoot. Hanging the pots or supports is the best solution because it ensures good air circulation around the plants. Remember that hanging plants will require more frequent watering: twice a day or more in warmer weather. A good compromise is to place the plants in hanging pots. This offers the advantages of both pots and supports. Some people prefer to repot their plants annually at the beginning of the growing season for best results.
Pests and other problems related to Catasetum:
Fungal and bacterial diseases of Catasetum are common due to the moisture levels and substrate they require to survive. Fungal diseases cause problems such as root rot, leaf spots, leaf discoloration, and flower spots.
The red spider mite is very harmful to these crops.
