I am sure its culture but what

[EarlV]

I have 5 hybrids that I purchased 2 yrs ago.

Last year's growth was small on all of them and this year's looks like it will be too. They get full unfiltered sun from sunrise until 11am like my Catts and they also get 5PM to sunset too (which the Catts do not). I fertilize them like crazy and they have good and extensive new roots(I unpotted the one in the picture to check) but they look like they are not growing well again.

What am I missing, again?

[Dorchid]

They require a ton of water and prefer to stay wet. The media in the pic looks to be very large chunk and free draining. Perhaps it’s drying too quickly and not holding enough water for them to really thrive and put on size?

[Roberta]

Also, Catasetinae should never be unpotted while in active growth (like now) Repotting time is while they are dormant. A small plant like that should be potted in something that will hold moisture (I use sphagnum but there are plenty of other approaches that other members have discussed). During the spring and summer (while in active growth), water copiously. You can't overwater these. Also fertilize fairly heavily. I use time-release in addition to my regular (light) fertilizing to get them enough. Then, as the weather cools, the leaves will dry and drop as it approaches dormancy. During dormancy, put it someplace where it will be ignored. You can repot in late winter, before new growth starts. Then, when new growth starts in the spring, resist the urge to water right away... you want the new roots to be 3-4 inches before you start watering.

For an overview of Catasetum culture check out Catasetum Culture . Also, isurus79, a frequent contributor to the Board, has several videos on the subject that are excellent. You can find links to these in a Search.

[estación seca]

Echo the water issue. Don't repot this one now. But stand it in a dish with an inch of water. It will suck most of that up every day.

[EarlV]

OK. So watering... They do dry out with the Catts. Small... They were not small when I purchased them they were all blooming or in bud. Though they are small not and all but one or two of the bigger back bulbs are left. They all look like this one.

[estación seca]

If you're letting them dry out like Cattleyas that is the problem.

[EarlV]

OK. Done. I certainly didn't think from the description in their culture sheets that I needed to keep them as wet as Phrags. (Which I have in shallow dishes of water.)

[Roberta]

During their growing season they need to stay quite wet. (Fred Clarke would say "Water like a monsoon") You can't water Catasetenae too much during the growing season. They will take whatever you give them. Then, in the fall (a month or 6 weeks from now), start to slow down watering and the fertilizing. When the leaves drop, stop watering completely. (If they don't go dormant by early January, force the issue by stopping the watering anyway) The treatment of this group is pretty much unique. During dormancy, if the pseudobulbs show signs of shriveling (usually if they're going to do it, somewhere around March or April) you can moisten the medium a little to perk them up, but only a little) But for right now, you need to get as much water into them as you can, to help build up reserves and get ready for the impending dormancy that will happen in a few months.

[Dorchid]

Sorry...I totally failed to emphasize that I was referring to watering in the growing season.

[isurus79]

Great advice above! Here's something to consider when repotting in the spring: PET Repotting Video II- January 2020 - YouTube