How to Grow: Catasetum Orchid care

General Overview:

The Catasetum Orchid is a beautiful vivid orchid species that is prized by growers for its versatility and beauty. This orchid is fairly easy to grow if you can replicate the correct conditions. Almost always deciduous, the pseudobulbous plants have strict growing and resting periods that they cycle through each year.

These vivid plants originate in Argentina, Brazil, Mexico, South America, and Central America where they can grow in sand, rocky conditions, and near ant colonies. This orchid develops fleshy waxy flowers, and the plants are unisex, which is rare in orchids. The male plants are identified by their bright colours and large size while the female plants are a yellow-green colour and have a smaller stature. Another distinguishing trait that sets this species apart is its ability to eject its pollen directly onto its pollinators. This care guide can be related to all Catasetums, Cycnodes and Clowesetums.

Growth Cycle:

Understanding the Catasetinae growth cycle is the key to successful culture. When the plants are in active growth, maintain a fairly constant root zone moisture and fertilise regularly to optimize new growth. When the plants are dormant little or no water is needed as the pseudobulbs store sufficient water and nutrients to survive their winter rest.

Early Season: Catasetums begin their new growth cycle in winter to early spring. Once you see new growth, re-pot your plants into new medium. Last year's roots seem to deteriorate during dormancy and are not as effective as the new roots at taking water and nutrients. Whether or not you repot, do not water your plant until the new growth has well developed new roots. Your roots should be 8 to 12 cms long, so for the sake of simplicity, do not water until your new top growth is 8 to 12 cms tall. This cannot be emphasised enough. Do not water until the new growth has become well established.

Mid-Season: New roots are established and the plants are rapidly developing their new pseudobulbs. The growth spurt during this 3 to 4 month period is surprising, often the plants will double in size. To keep pace with their growth rate, the plants require constant moisture and regular fertilization. Normally you will water 2 or 3 times a week. A balanced fertilizer at full strength is suitable for this rapid growth or you can top dress with a controlled release fertilizer and apply water soluble fertilizers at a dilute rate, say 2 grams per Litre. Light levels at or above those suggested for Cattleyas will help insure strong good growth and flowering. The fruits of your labor will begin to pay off as the flowering season begins.

Late Season: In the late autumn the plants will begin to enter the dormancy phase, caused by the maturity of the pseudobulb, shorter day length, cooler day/night temperatures and a reduction of root zone moisture. The first signals you will observe on your plants are yellowing and browning off of the leaves. As a general rule, this will happen by mid-November, at which time you will stop fertilizing them and reduce watering by half. When all the leaves have dropped or by the end of December, stop watering the plants. Watering during dormancy should only be done it the plant bulbs shrivel severely. Usually a single irrigation is sufficient to restore the bulbs.

Light Requirements:

Catasetum orchids are sun-loving plants, and in their natural habitats many species grow prolifically in full sunlight. Unless the strong air movement as found in the natural habitat is available, the grower should provide some shade as well. For the surge of new growth in the springtime, Catasetum plants should be positioned to receive all the sunlight that they can tolerate, depending on their origin, but as their pseudobulbs mature, thought should be given to whether male or female flowers are desired.

Catasetums are known to produce male or female flowers based on the amount of light and humidity they are subject to.  High light and low moisture tend to induce production of female flowers while low light and high humidity produce male flowers. 

A few species, such as Catasetum Cernuum, Catasetum Hookeri, Catasetum Longifolium, and Catasetum Rooseveltianum, should be grown in moderate to deep shade.

Temperature Requirements:

These orchids are native to hot tropical areas and grow during the rainy summer months. During this growing period, day temperatures of 27°C to 38° C and night temperatures of 16° to 18° C are beneficial. After growths mature, temperatures can be reduced to 12° C at night, with day temperatures of 21° to 30° C. In general for all but a few species, the grower can regard 18°C as the ideal minimum night temperature and not to be overly concerned about daytime highs as long as they stay below 39°C.

Water Requirements :

Catasetums require plenty of water during their growth phase.  This starts when new growths appear with the onset of the pre-monsoon showers.  Watering should be gradually increased as they mature by the end of the monsoon.  Once the pseudobulbs are mature, watering should be reduced and tapered down until they start dropping their leaves which is an indication that water should be withheld completely except occasionally to prevent shrinking of their pseudobulbs.  It is at this time that they will come into bloom.

All mounted, basket-grown, and unconventionally potted Catasetums may be watered every sunny day during the growing season, provided conditions are such that they dry off relatively quickly. In the case of conventionally potted adult plants, it should not be necessary to water more than once or, at most, twice a week. These species like to dry out at least slightly between waterings. When you water, do so thoroughly, allowing the water to flow freely from the bottom of the pot after saturating the entire contents or penetrating the entire root mass of mounted and basket-grown plants.

"A good rule of thumb is that the more leaf surface and root system a plant has, the more water it requires"

Humidity Requirements :

Catasetum orchid tolerate an environment with 40 - 60 % relative humidity during their growing season, but for optimal development of new growth and flowering, 70 % is recommended. This can be provided in the home by placing the plants on trays of gravel, only partially filled with water so that the plants do not sit in the water. Air should always be moving around the plants to prevent fungal or bacterial disease, especially if high humidity or cool temperatures exist. Higher humidity increases the plants' ability to withstand and benefit from their quota of light, and it also slows the evaporation of moisture from the potting medium in which they grow. Higher humidity also reduces the likelihood of spider mite attacks, since the little critters prefer warm and dry conditions.

Fertilizer Requirements :

Catasetum orchids have a reputation of being heavy feeders while actively growing, and the concept of heavy feeding should be applied both to the strength of the fertilizer and to the frequency of fertilizing. The standing goal should be to push the plants to the limit, to make them as strong, healthy, and dynamic as possible. Fertilize with an appropriate formulation at least every week during the growing season, or fertilize with 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 while plants are in active growth, slowly tapering off as pseudobulbs form. As the leaves begin to unfurl, and well before flowering, add a high-phosphorus formula to develop big, strong pseudobulbs capable of producing robust inflorescences. Any of the soluble products with a large second-digit number of N:P:K constitute a good source of phosphorus. A blossom- booster formulation should be used in the autumn, except for plants that normally bloom in the spring.

Recommended Fertilizers:

• Balanced Fertilizer for Growth: 20-20-20 (NPK) – 2 grams per litre of water – Spray once in every alternative weeks (14 Days) - Only on Mid Season

• High-Phosphorus Fertilizer for Blooming: 0-52-34 (MPK) – 1 gram per litre of water – Spray on every alternative weeks (14 Days) - Towards the end of Mid Season

Potting , Media and Propagation :

Potting should be timed to coincide with the initiation of new growth, usually in the spring. New roots will be produced quickly at that time, and plants will experience minimal setback. These plants have vigorous root systems and require a rich, moist potting medium such as coconut husk chips during the growing season. Many growers bare-root their plants during the resting period to ensure dryness at that time. Fine-grade media are common for smaller pots; medium-grade media are used only in larger pots. Sphagnum moss is used successfully for plants in many areas, as it provides tremendous water- and fertilizer-holding capacities.

When well grown, these orchids can be divided down to one mature pseudobulb and will then flower on the next mature growth. Hanging the pots or mounts is best because it provides good air movement around the plants. Remember that mounted, plants will require more frequent watering - two or more time per day in the hottest season. A good compromise is to place the plants in pots that are suspended. This offers advantages of both pots and mounts.  Some people prefer to re-pot their plants every year at the beginning of the growth period for best results.

"Most plants have a dormant period and, when it occurs, it must be recognised and respected"

Pests and Other Catasetum Related Problems :

Fungal and Bacterial Diseases of Catasetum are common because of the levels of humidity and substrate they need to survive. Fungal agents cause problems like root rot, leaf spots, leaf blights and spots on flowers.

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