Catasetum Culture Big Picture

[skirincich]

Hello,

I would love to hear from catatasetum growers about what is understood about the challenges they experience with these plants. I am aware that Fred Clarke and others have worked very hard to communicate their knowledge. Not a month goes by when I speak to experienced local society members and guest speakers and hear how they have given up on these orchids. I understand that some people struggle with the prospect of withholding water for many months.

After purchasing about 5 of these plants from Fred in the spring of 2020, the plants all thrived and bloomed. I was able to give them a reasonably warm, and humid dormancy and the temptation to water was easy to resist while watching for excessive shriveling of the bulbs. The plants have not done as well since. I have tried dividing a few while being careful about the new small roots. Some of the plants burst from dormancy and some seem to never attain great vigor through the summer.

Here are some issues I am regularly considering:

1. Watering during dormancy
2. Watering before new roots are sufficiently developed
3. Dividing at the wrong time
4. Dividing into small groups of pseudobulbs
5. Water, fertilizer and light issues
6. Can/should old roots be trimmed to simplify repotting versus slip repotting
7. Bug issues
8. Dormancy initiation

I continue to ask if the problem is not the information provided by the experts but perhaps the delivery of the information does not hit the mark? Are small but important details missed? I find it helpful to understand both the DOs and the DON'Ts.

Thanks,
Steve

[Louis_W]

I'm not the best grower of these orchids so I can't chime in too specifically about their care, but I can say that if your plants are not thriving then dividing them should be off the table generally. I would wait untill the plants are mature to start dividing. I know Fred says that he keeps plants divided down to 2 or 3 bulbs, but his plants are already mature size with huge bulbs and he knows they will double in size by the next year.

[Keysguy]

I'm not sure I can be any help Steve because I'm not growing in New England any more. Do you have a greenhouse or are you growing on windowsills, under lights?

I have a half dozen in my collection down in the Keys and they are absolutely on autopilot. The only thing I can think of that might be your issue is that if you are not in a greenhouse, the summers (true growing season) are just too darn short up here for some plants. And when I say "growing season" I mean warm-hot temps day & night and lots of food and water, water, water and preferably rainwater.

The occasional issue I have is that they grow so robustly and it stays warm so late into the year that they sometimes really want to fight dormancy.

And as far as the dormancy period goes mine stay right in their pots but I move them out of the shade house and put them in a spot under my porch where the bulbs get morning sun for 2-3 hours and not a drop of water for what is usually around 4 months. Then as new growth gets to the right size I repot/divide and put them back out in the shade house and as the Brits say "Bob's your uncle".

[skirincich]

Thanks. I have never divided a plant that was struggling. From May though September, the plants are outside under 50% shade cloth. Both rainwater and tap (100 ppm TDS) are used. A past conversation with Fred indicated that dormancy should not include a significant dropping temperature. In the fall and winter, the plants are in my basement grow room that is maintained at 65-70F and roughly 70% humidity. I had some great growth last summer, but less so this summer.

[estación seca]

They should tolerate full sun that far North, and will grow better with it. Are you following Fred's water and fertilizer recommendations on his Web site?

[mook1178]

I second what ES says.

I am in Delaware and mine get full sun most of the day.

[Roberta]

Also, these are heavy feeders during the growth period. The only way I have found to give them enough is to add a top-dressing of time-release fertilzer (Nutricote, Osmocote, Dynamite etc) in the spring as soon as they get to the "water me" size. (Fred Clarke fertilizes at every watering, something I can't manage, but the time release does help a lot) And during the growing season, lots of water. Like sopping wet most of the time. I move them outside once nights get above 55 deg F, the light and air movement are better than in the GH and they do need bright light - just short of the "sunburn" point.

[vanda2020]

I am in West Texas, so we get hot, hot, hot. I grow them as Fred says to do. For me, they start off really slow in the spring. In fact, I did not start watering any till late May, and we were starting to hit some high heat days. They need the longer light hours, higher humidity, and higher temps to start to get the message to turn on. I had a few this year that would not turn on. These were all new buys from the last summer. I gave no water to them, treated them mean, then I put them into a grow tent with higher humidity and longer light hours, thinking maybe this would finally turn them on. Still nothing. Once we had almost every day 100 degree days and still nothing and the bulbs shriveling to nothing, I gave a little water. They never rotted or anything, they just refused to grow. I lost four plants this year, one of them was a Cynodes Wine Delight which teased me with its two side buds thinking about growing. They never did. One dried up and then finally the other one. Catesetums can have viruses too just like any other orchid. I was reading that a virus can make for a weak frail plant that fails to do what it should. Out of almost thirty catasetums only four failed to turn on that is not a bad thing. I bought more from Sunset valley and other vendors this summer, so you do what you can and move on. Make sure you sterilize your cutters between plants.

[Keysguy]

I second Roberta's comment on time release.
When I repot I put in 3 layers. Just off the bottom, middle and top. Got that approach from Fred years ago.

[Dorchid]

Just a question, but are these all true catasetum or are they “catasetum”? I ask as I tend to lump them all into catasetum when I should be saying catasetinae. I bring this up as some genera in that subtribe may be more difficult to grow than others. For instance, my mormodes don’t grow near as well as my catasetum under the same conditions. Of course, that could be a conditions/culture issue…