Catasetum coming out of dormancy and first roots aborted despite dry media?

[Friday'sChild]

Hi everyone!

This is my first time posting, though I have been using these boards as a resource since I started growing orchids five years ago and can't thank everyone enough for sharing so generously.

My current issue I'm experiencing involves my Catasetum 'Black Pearl'. This will actually be my fourth season growing it, though it has never bloomed, so obviously I am still trying to perfect it's culture

For the first two years, each seasons' growth was larger than the year before; the plant seemed to grow vigorously, putting down lots of good roots. Around Halloween, it would start to loose it's leaves, finally going completely dormant by Christmas, and would start showing new growth in February. Watering usually starts around early May.

Last year, the new roots just never seemed to grow well; only growing a couple of inches, no matter how long I waited to water. I finally gave up waiting about the end of June, once the back-bulbs had begun to wither badly. It ended up losing it's oldest back bulb, but the rest recovered, eventually. But by the end of the season, the new pseudo-bulb only reached about 1/3 of the size of the previous year's growth.

This year, though the plant seems to have tried to grow a fair number of new roots, many of them have aborted and turned brown at the ends once they reach the dry media, about a month ago now, and new growth of the roots seems to have largely stalled.


My growing situation:
I live in southern Ontario. My Catastetum plants grow indoors, in a fully south-facing window ( in front of sliding patio doors, and the space behind me is a children's play park, so no buildings obstructing the light for quite a space )

I slow my watering in November, completely stopping by mid-December. Generally, I don't resume until the majority of new roots are at least 3" (excepting last year's disaster). I start by watering the opposite side of the pot as the new growth, usually with 1/2tsp of kelp extract mixed in 1cp of water, gradually increasing watering and fertilization as the new growth takes off.

I re-pot in new media each February, once the new growth has started.

I am really not sure what is happening here, and would really appreciate any insight anyone can offer? The back-bulbs are already quite shrivelled-looking, and I think I may have to begin watering lightly, soon, despite the lack of good roots.

This year is looking to be a repeat of last year, and I hate to think that I am going to lose this orchid to slow decline

[estación seca]

My three guesses would be movement of the plant scraping the new root tips against the medium; snails or thrips eating root tips; or low humidity.

[tmoney]

howdy, and officially welcome to the ob! only posting to offer a little empathy as basically your experience with these plants mirrors ours exactly! only exception is that our roots have come back in fine this year, but, like yours last year, have stalled out. the fans are growing great but the roots aren't getting any longer . no blooms for 4 years on now 5 mature plants (2 being black pearls).

some of the things that others have said to help us out is upping the humidity and light hours during winter. increasing summer light intensity and duration, and trying slow-release ferts as the best growers seem to use this on the catasetums. we hope you have better success than us!

edit to add: we are not alone as im not sure if you watch "hello plant lovers" on YouTube. he is in Australia, a pretty dang good grower, and has had the same experience as us. so we aren't alone!!! don't give up!!!

[Friday'sChild]

Movement against the medium may indeed be a possible culprit - I have a 15lb cat who likes to rub against the stand that these orchids are on, and is certainly aggressive enough to cause it to wobble from time to time ...

Low humidity may be a factor worth investigating, too. I just started running my first humidifier in the room recently, but it is an open-concept type room, so very possible it is not as effective as I would hope.

Thank you so much for the suggestions - you've definitely given me a few things to consider!

I must admit I am still very much an amateur grower *lol*

[Canadienne]

Hi I’m in southern Ontario as well. My issue was low humidity, lower than 50 percent in the house at times.
Poorly growing roots being the main issue. Mine winter in garage that doesn’t go below 10 celcius. Growth started in March, I put them in clear plastic pots, then in a large clear plastic container ( from can.tire) with a lid and with egg crate in the bottom. Added 2 cups of water ( not touching pots) , closed lid and sat outside in sunny spot. Temp up to 34 celcius with humidity between 75- 80 percent through the day. Opened lid at night, box in the house, small fan, temp down to 18 celcius. No mold or spotting, roots just reached 5” .I just started watering a week ago. They will reside outside without box and in full sun as soon as day temps go over 20 c and no lower then 15c at night. I have good luck with them that way. On realllly hot and dry days I put them back in de plastic box without lid but water in the bottom and in light shade from 11 till 4.

[Friday'sChild]

tmoney - thank you so much for your encouragement; and for letting me know that I am not alone in this!

It is hard sometimes not to feel like you MUST be doing something really obviously wrong, isn't it? .

I hadn't really considered increasing the light in winter months, given that it is basically dormant, but then again, I am far enough north that the light levels are decreasing even by late August, when it is still growing, so yeah, should have thought of the fact that it would benefit from supplemental light.

I really appreciate your suggestions - do you have a brand of slow release fertilizer that you recommend? I've always been nervous of over fertilizing , but I guess given the growth that these guys go through, that is not as much of a concern, is it? *lol*

I will check out your youtube recommendation, as well - always love finding new channels that have quality advice! Thank you so much

---------- Post added at 11:20 PM ---------- Previous post was at 11:10 PM ----------

Canadienne - oh, wow. I would love to see a picture of this setup, if you have one

I had never considered growing them outside- guess something in my brain just didn't associate 'Canada' with 'growing tropical Orchids' , but of course, we have warm enough temps in the height of summer to do so, don't we?

[Roberta]

You mentioned that you repotted after new growth has started. Were there any roots then? If so, another source of "movement" that could have damaged them. I only repot Catasetinae when they are fully dormant - so more like December/January.

[Friday'sChild]

Roberta - This is a good thought.

I am careful to re-pot before root growth starts - basically, just when the first 'nub' appears, so I can be sure to orient the new growth towards the centre of the pot - but you're right, this is a good reason to be extra careful that I never wait until root growth is underway!

[isurus79]

I think the growth is moving higher up and away from the media. This exposes the new roots to the air for longer and low humidity can cause them to abort. I'd suggest soaking some spag, wring it out, let it get mostly dry, and then stacking it against the new roots to hold at least some humidity around them. Increasing the ambient humidity can help too.

[Friday'sChild]

Thank you everyone, for your insights

@isurus79 - I have seen marked improvement since implementing your suggestion; several tiny new roots are attempting to grow, and the ones that had been growing straight up are now curving back along the plant, towards the damp sphagnum.

The back bulbs are so badly withered at this point, I am nervous as to whether they may be lost, and how well this plant will recover for next year. I have heard they are pretty resilient, so fingers crossed that next year will be a new year, with no mistakes in it....