Catasetinae Plant Culture

Cycnoches, Catasetums, Mormodes, and Clowesia

The cultural information below is a generalization and will apply in most situations; however each grower and growing environment is different. I encourage you to make adjustments based on your own experience and growing conditions. It would also be advisable to seek out other growers in your area for their advice and insights into these amazing orchids

Catasetum exspansum

Here is what to look for:

Early spring

Catasetinae have a distinctive growth and rest period (dormancy). For best plant growth it is important to understand and respect these growth phases. When the plants are in active growth maintain constant root zone moisture and fertilize regularly. This is essential to optimizing the development of new growth. When the plants are dormant little or no water is needed as the pseudobulbs store enough moisture and nutrients to survive the dormancy Catasetinae plant culture is not difficult.

All it takes is an understanding of the seasonal growth patterns. The plants' vegetative state signals to the grower their changing needs. Interpret the signals and make the appropriate cultural adjustments.

Catasetinae begin their new growth in early spring. However, watering should wait until the new growth has well-developed new roots. This means you should let the new roots grow to an approximate length of 75 – 125mm, another measure is to look at the new leads, when the new leaves begin to unfurl is also the right time for watering to start. Let me emphasize this point. Wait to water until the new roots are well developed and the new leaves have unfurled. The waiting to water is not easy; my natural instinct is to begin watering when I see new growth, but I have learned through trial and error that it is better to wait to water than start watering too soon. I also believe that Catasetinae roots deteriorate during dormancy, and in the following year they are not as effective at taking up moisture and nutrients. This makes the new roots vital in the plants' health. This reinforces the message about not watering too early.

Mid-Season

Once the new roots are sufficiently developed, this is the period where the plants are rapidly developing their new pseudobulbs. There is a surprising amount of growth that occurs in these 3-4 months; often the plants will double their size. Due to this, the plants require constant moisture and regular fertilization. In most cases, irrigation will be needed 2 or 3 times a week. A balanced fertilizer at full strength is suitable for this rapid growth. Light levels at or above those suggested for Cattleya will help insure strong good growth and flowering. This is the time when the fruits of your labour will begin to pay off as the flowering season is in underway. (continued)

Late Season

Sometime after flowering, in the late autumn and with some plants into winter the plants will begin to enter the dormancy phase. Understanding the signals of the onset of dormancy and the factors triggering it are important to a healthy plant culture. The plant's first signals are the yellowing and browning off of the leaves, at this time stop fertilizing and reduce watering by one- half and when most leaves are yellow/brown and have dropped off cease watering altogether. The general rule to follow is: by mid- May stop fertilization and reduce watering by one-half. Most leaves should have yellowed or fallen off by the beginning of July. However, if the plants still have leaves all irrigation should be stopped at this time.

Catasetum pileatum

The onset of dormancy is caused by several factors; the maturity of the pseudobulb, shorter day length, cooler day/night temperatures, and a reduction of root zone moisture. In most of the country dormancy occurs naturally; however when the plants are cultivated in warm growing areas such as in North Queensland or in the home or under lights sometimes dormancy needs to be encouraged. I have found that stopping watering in June regardless of the number of green leaves will trigger the start of dormancy providing flowering has finished.

Note: Watering during dormancy should only be done it the plant shrivels severely. Usually a single irrigation is sufficient to restore the bulbs.

Here's a summary:

As the new growth develops wait to irrigate until the new roots are well-developed and are 75- 125mm long and the new leaves have started to unfurl (don't be in a hurry to water; it is better to wait). Irrigate and fertilize frequently while the plants are in active growth, they are very hungry feeders. Stop fertilization and reduce irrigation by one-half around by mid-May or June. Cease watering by the begining of July.

Light levels:

Catasetinae like light levels comparable to Cattleyas at about 2500-4000 foot candles (fc) However, the plants are widely adaptable and do well with light levels as low as 1500 fc and as high as 5000 fc. For optimal growth I suggest a Northern exposure or a location where all the plants will receive plenty of bright, filtered light

Potting mix:

For mature plants I have been using a 3:1 of mix of fine ‘Kiwi Bark’ and medium Perlite.
For seedlings up to a 75mm pot size I like to use New Zealand sphagnum moss s. However, this genus is not too particular in what it is potted in, and any well drained media will work well.

Containers:

I prefer to grow in plastic pots; however clay pots, baskets, and cork slabs will all work. Catasetinae don't like to be over potted; select a pot size that will allow for 2-3 years of growth.

Fertiliser:

When in active growth, use your favourite fertilizer once or twice a week, I have found it hard to over fertilize these plants at this time.

Air movement:

Catasetinae enjoy abundant air movement. If you are growing in a greenhouse (enclosed )use air circulating fans. Also, hanging the plants allows for maximum air movement around them and often they do best hanging.

Repotting and Dividing:

Is done as the new growth is just starting to develop and before the new roots start to show (remember no watering until the roots are well established, 3-5” long). Unlike most orchid plants Catasetinae do well when divided in to 2 bulb pieces. Divisions are made by cutting with a sterile tool or by pulling the bulbs apart. I try to keep the size of my divisions between 2 and 3 bulbs with no more than 5 bulbs on a plant as this number of bulbs will encourage female flowers.

Insect pests:

Catasetinae are generally pest free. However spider mites are attracted to the soft leaves of these plants. Spider mites are quite small. They live and feed on the undersides of the leaves.

Take care in checking for them as the plants are developing the new leaves and control them by hosing the underside of the leaves every morning as this will dislodge the pests. If the infestation gains a foot hold on your plant then treat with a recommended miticide.

Although the leaves will drop off during dormancy this is not an excuse to not treat for them.
It is for this reason I grow my Catasetinae hanging high in my greenhouse this also ensures the plants get plenty of light during the growing period.

Catasetum Olga

Once the basics are understood they are very rewarding orchids to grow. Once the plants start their flowering cycle it is generally very hard to stop them. If a spike gets hung up on something I simply cut it off and the plant usually grows another to replace it.

This article was reproduced with the permission of Fred Clarke of Sunset Valley Orchids, USA, with adaptations for Australian conditions.

Author: Mal