General AOS Culture Sheet and My Own Grow Experience Featured

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This unusual group of orchids offers fascinating, waxy flowers that often have the peculiar habit of discharging their pollen masses (pollinia) onto pollinators. Almost always deciduous, the pseudobulbous plants have strict growing and resting periods. Most flower before entering a dormant period when they drop their leaves.


Light should be strong, especially near the end of the growth period. Early in the annual growth cycle, plants will tolerate less light, from 1,500 to 3,000 foot-candles. Plants grow best with light levels of 3,000 to 6,000 foot-candles, or one-half to three-fourths full sun. As pseudobulbs mature, harden them by giving slightly more light.


Temperatures reflect the fact these orchids are native to hot tropical areas and grow during the rainy summer months. During this growing period, day temperatures of 80° to 100° F and night temperatures of 60° to 65° F are beneficial. After growths mature, temperatures can be reduced to 55° F at night, with day temperatures of 70° to 85° F.


Water is a critical factor for the production of large pseudobulbs that result in best flowering. A great quantity of water must be stored by the plant in a relatively short growing season. Water heavily as new leaves are forming. As the pseudobulb matures, gradually reduce watering frequency. Leaves will yellow and drop. At this time, watering should be stopped completely until new growth begins. Water during this dormant period only if the pseudobulbs shrivel severely.


Humidity should be 40 to 60 percent. 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. In the greenhouse, the humidity is best increased by use of a humidifier. Evaporative cooling increases humidity while cooling the air.


Fertilize and water regularly to produce strong pseudobulbs. Use a highnitrogen formulation (such as 30-10-10) while plants are in active growth, slowly tapering off as pseudobulbs form. A blossom- booster formulation (such as 10-30- 20) should be used in the autumn, except for plants that normally bloom in the spring. Frequent applications of a dilute concentrations of fertilizer are more effective than occasional applications of strong concentrations.


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 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. Some plants can be grown on slabs of tree fern or other material, which makes it easier to keep them dry during dormancy; however, it is harder to keep them moist while growing. When well grown, these orchids can be divided down to one mature pseudobulb and will then flower on the next mature growth. Spider mites are a common pest of these orchids when in leaf. Control spider mites by keeping humidity high or spraying with recommended miticides.


SOURCE: AOS Catasetum Culture Sheet



Below is a compilation of Newsletters from Sunset Valley Orchids and basic notes and observations of my own grow expeirnce with Catasetums for 2019


Coming out of Dormancy


Last year I tried out the "Catasetumarium" techique outlined on a popular streaming video source on the Internet (using 2 2-liter clear plastic soda bottles) and it seemed to work very well on the three Catasetums I had then.  I may repeat that process again this year with all of my Catasetums.  The only change I will make is definitely waiting for the new growth to get about 3-inches in lngth, and just before the roots begin to show.  although I do not notice any setback.


Sunset Valley Newsletter - Spring


For most parts of the country it's finally spring! Your Catasetinae should be or are just getting started to grow. Most of you along the southern edge of the country have already started watering and fertilizing. I am hearing reports from many Southern growers that most of the new growths are 6"-12" tall with new roots 3"-6" long. This is the time to start watering! The growers farther north (myself included) may still have a few weeks until the new roots are 3"-6" long. Remember: not all Catasetinae come out of dormancy at the same time, so you may have some plants showing well-developed roots while others will be just starting to root. Begin watering and fertilizing those plants that are ready and hold off on the ones still needing more time; this is a good practice to develop.   
Catasetinae like lots of light and air movement; be sure your plants are getting the correct amount now as this will really help them get a good start on their seasonal growth. I keep mine under 40% shade with lots of air movement day and night.
Ideal temperatures in early spring are 60 degree nights and 75-85 degree days, humidity should be at 50% or higher, this is a great help to the plants and new roots.  
I start the watering season using ½ tsp fertilizer per gallon of water, and then, as the days get longer and the temperatures warm up in late June and early July, I increase the fertilizer to 1 tsp per gallon through August, before switching back to ½ tsp from September through October.  
Don't forget that Catasetinae prefer to be re-potted or divided with the onset of new growth just before the new roots start to show.  
Early in the growing season is when spider mites can get a foot-hold on your plants. Be diligent and check the undersides of the new leaves regularly. If mites are detected, spray immediately. They can quickly get out of control if early action is not taken!    


Sunset Valley Newsletter - June


Your Catasetinae should in growth by now, with many growers in southern parts of the country already seeing some plants bloom. Watering and fertilizing should be in full swing for most everybody. This is when your plants really put on their best growth. Increase the fertilizer to 1 level tsp. per gallon from now through August, switching back to ½ tsp. from September through October.  
Remember - no more re-potting at this time. However it is ok to 'slip-pot' into the next larger pot size, just wrap more moss around the existing and slip in to the next pot, being very careful not to damage those important new roots.    
This is when your Catasetinae can really take advantage of lots of light and air movement to help push and develop large new growth. Ideal temperatures in summer are 80-95 degree days and 60-75 degree nights, with humidity between 40% and 80%.
Keep an eye out for the spider mites, which can get a foot-hold on your plants (and they have 8 feet!). Be diligent and check the undersides of the new leaves regularly. If mites are detected, spray immediately. They can quickly get out of control if early action is not taken!


One thing I definitely learned for next growing season is the need to rotate the Catasetums (plants grow towards the sun's light) and this rotation should help in Catasetums that grow vertical, not horizontal.  Horizontal growth takes up space and perhaps also deprives other Catasetums access to bright light.






Catasetinae Plant Culture for Late Summer and Fall
Your Catasetinae are in full growth now, with many growers around the country seeing their plants bloom. This is my favorite time of year! Watering and fertilizing should be in full swing with your plants bulbs mature or reaching maturity now. This is when your plants are putting on their best growth. Remember to switch back to ½ tsp. in early October.
No re-potting at this time, the roots are well-developed and will resent being disturbed. If you were negligent (how could that be?) it is better to wait until next spring at this point.
This is when your Catasetinae can really take advantage of lots of light and air movement to helping to push and finish the development of the new growth. Ideal temperatures now are 75-95 degree days and 60-70 degree nights, with humidity between 40% and 80%.
Still keep an eye out those pesky spider mites, as they can get a foot-hold on your plants as they have 8 feet! Be diligent and check the undersides of the new leaves regularly. If mites are detected, spray immediately. They can quickly get out of control if early action is not taken!
Looking ahead, with autumn just starting and that means winter will be upon us soon, yeah, I know, it arrives faster every year. We are still about 2 months away before you start to see the indications of leaf yellowing and leaf drop signaling the beginning of dormancy. This is when you should stop fertilizing and cut back on watering frequency. You want to simulate the end of the wet season, as it happens in nature. This change in culture will cause the pseudobulbs to harden off, in preparation for dormancy.




It's November! 
Catasetinae plant culture
As we can all tell the weather is changing and your Catasetinae should now be in their final stages of growth. This was an excellent year for Catasetinae; many growers from around the country reported a fantastic flowering season. The first signs of dormancy should now be evident, with some areas of the country well in to dormancy. This is the time of year when you stop fertilizing and begin to decrease irrigation frequency, in effect lengthening the dry period in-between watering.
In nature the rainy season is nearing its end, the rains are less frequent, nights are cooler and day length is shortening. These are the environmental factors that start the dormancy process. With less rain fall fewer nutrients are moved to the root system (thus stop fertilizing) and the roots stay dryer longer (thus reduce irrigation frequency). This increasing dryness is an indicator to the plant to harden off their pseudobulbs in preparation for the 2-4 month winter dry period. Hardened off bulbs are better at storing water through dormancy. Humidity should be maintained at 40-60% however brief periods outside this range is not a problem. Maintain light levels and keep night temperatures at or above 55 degrees.
No re-potting at this time, the roots are well-developed and will resent being disturbed. If you were negligent (how could that be?) it is better to wait until next spring at this point. As soon the new growth begins in the spring, that's the time to re pot, as you can now see the best way to position your plant in its new pot. With Catasetinae the roots follow the new growth usually several weeks behind. In nature, the roots grow out and then the rains start. So, as I have said many times, "wait to water until the new growth has new roots 3-4" long." This gives the best results as large healthy root systems make for strong healthy bulbs and better yet, excellent flowering.
One of the great attributes of the Catasetinae is their deciduous nature, if you experienced leaf damage, don't worry, as those leaves are going to drop off and next spring/summer you will have a new set. How many orchids are that forgiving when the leaves are damaged?
When walking around the greenhouses these days it looks like almost everything is blooming! This is my favorite time of year as there are Catasetums in flower, it's the start of the Cycnoches blooming, and the first of the Mormodes are in spike! But there is still more to look forward to as the blooming season for Clowesia rosea hybrids begin in December and January. These late season plants bloom on deciduous bulbs, with inflorescences cascading over the side of the pot with many fragrant flowers.


As my Catasetums enter their winter rest (yellowing of the leaves) water will be withheld and the moss allowed to dry.  FOr the record I will unpot and clean each Catasetum and compare the roots to see if they did in fact enter and dive into the water reservoir.  As you pour water onto moss it becomes compacted.  This needs to be evaluated as this compacted moss might inhibit growth and the best way to combat this situation is adding something to the moss medium to establish pockets like a perlite (sp?) or perhaps large sized bark. All moss will be discarded - it has become swollen with salts from fertilizers and it just makes sense that the next year be a fresh start.  Some trim away old roots.  I might follow this but leave a few to serve as anchors.  I doubt I will divide any of the Catasetums this year (2019). 


December 2018 Sunset Valley Orchids
Catasetinae Growing tips
What a great year for the genus! Feedback from Catasetinae growers confirms this was a spectacular growing and flowering year. There have been many awards given by the American Orchid Society judges. Congratulations to all of you who received them! 
Now that winter has clearly arrived, your Catasetums should have matured growths and be mostly done flowering, Cycnoches will be finishing their blooming, Mormodes should be flowering now, and Clowesia should be starting soon.
Those of you in Florida and southern states may already have dormant plants. Those in more temperate areas like here in California should be seeing the starts of dormancy with the lower leaves starting to turn light brown and drop off.
The first indications of leaf yellowing and leaf drop signal the beginning of dormancy. This is when you should stop fertilizing and cut back on watering frequency. You want to simulate the end of the wet season, as it happens in nature. This change in culture will cause the pseudobulbs to harden of, in preparation for dormancy. When most leaves are yellow/brown and have dropped off, cease watering altogether. This marks the start of the dormant period.
The onset of dormancy is caused by several factors: the maturity of the pseudobulb, shortening day length, cooler day/night temperatures and a reduction of root zone moisture. Generally, this process occurs naturally; however, when the plants are cultivated in warm growing areas such as in the home or under lights, dormancy sometimes needs to be encouraged. I have found that stopping watering in late December, regardless of the number of green leaves, will trigger dormancy in plants that are resisting the necessary transition.
By late December, it's important to get your Catasetinae into the dormant stage; to provide them with an adequate rest period so that they will 'wake up' early in the spring to a long growing season.




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