Question on culture

[gngrhill]

This is kind of a continuation of the previous thread on dormant catasetums. I have a new growth (tiny ) started with tiny little root nubs started. I know I'm supposed to wait until the roots are 3 to 5 inches long before watering . The problem I need help with is that the old roots are very tightly packed in totally dry spaghnum. If the new roots grow into that I will never be able to tell how long they are. Also, as the new roots grow, what should I do with the old roots that are so tightly packed ?Should I repot ? Into what medium ? when ? Any advice appreciated.

[fishmom]

Hmm, I've got one just like that; I got it last month. The dried out sphag is rock hard and I'm picking away at it gradually, but I don't think I will get it all off by the time to repot.

Usually I repot before the roots are 3 inches long, and then I don't water until I think the roots are long enough. But with this one, I think I will wait until it is time to start watering and then moisten the sphag to let me remove it more easily. The new roots are VERY tender and easy to damage, so I will have to be very careful. I doubt that the roots will go into the sphag much, as it is so dry and they are looking for moisture. I expect them to go along the surface of the moss and down along the side of the plastic pot.

I use a fine textured mix for oncidiums or seedlings for my catasetums. It has fine orchiata and some other stuff in it, perlite, turface, and the like. I get it online as I am too lazy to keep all the ingredients here and mix my own.

I imagine that katrina has experienced this problem and I hope she will chime in with her usual good advice.

[estación seca]

I heard Fred Clarke speak. He said he believes Catasetums lose 90% of their old roots each dormancy, so don't worry about them. Regard the plant as rootless until it grows new roots.

From experience here, don't pick at the dry moss; leave it alone. The new roots will mostly grow over the hard sphag. When you finally water, the moss will become as soft as a baby's bottom and the new roots will grow down into it. Most orchid people fuss with their plants too much, and that's like picking at scabs.

[katrina]

I'm happy to chime in! What I do kind of goes against the regular advice...but it works for me. I just finished doing all my Ctsm repots last weekend and during the process I noticed that those potted in the straight sphag the year before had the most extensive roots I have ever seen. All my roots are good but those in straight sphag were more than double the thickness and at least quadrupled in numbers. So...all went into straight sphag this year. I use a mix of clay and regular houseplants, plastic pots...just depends on what I have that can fit the plant's root ball. I do tend to overpot these guys a bit because they produce massive root systems. And, even w/our torrential rains last summer...no root rot to be found. If the pot was a good deal too deep, I didn't want inches and inches of sphag in the bottom so I used leca or large orchiata in the bottoms to take up some of that space.

I typically do my repots just as they are breaking dormancy. For me, I tend to damage the new growths/roots when they get farther along so I like to do it early in their development. I also want to get them all done w/in a couple of days so some are still dormant, a couple are already being watered but the majority just have wee little nubs of growth and roots.

I wet the existing medium thoroughly in order to get them out of the pots w/out doing damage...I work them out of the pots and shake off whatever is loose and/or pull off some of the old sphag but only as much as easily comes off and then they go right into the new pot and I back-fill.

The new sphag is moist but it's not soggy. Just moist enough to get the plant settled properly and then once it's done, it goes back on the shelf and there is no more watering until the growth(s) is unfurling it's leaves. For most of mine that means they are usually 3 or 4" tall. Keep in mind...my lights dry thing out quick and whatever moisture is on the plant or in the pot...isn't there for long.

On some of these guys it's hard to see the roots if they instantly start to bury themselves so a couple of years ago I started using the leaf structure as a way of gauging when it's time. That 3" to 4" amount is typically when I see the tops of the leaves starting to open up and out. In these early phases I'm very careful to avoid getting water down into those new growths because some will rot out rather quickly.

FWIW - I know many people say that Ctsm loose the majority of their roots from one year to the next but I don't see that w/most of mine. Some do, of course, but the majority of mine carry healthy, viable roots until the growth is absorbed to make the newest growth. Or, until I divide the plant and cut some of them up.

That's what I do and it works for me but, again, it kind of goes against much of the advice given so if you opt to try it, then be careful and keep in mind my growing conditions might be radically different. I know some people unpot these things and lay them on a shelf until they see new growth and they are very successful growing them that way so I honestly believe they are very adaptable to just about anything. As long as we don't water them in the middle of their dormancy...they are really pretty easy growers.

[isurus79]

Repot now, before the roots come in at all. That way, you don't have any chance to damage them.

As Katrina already mentioned, spag is one of the preferred methods to grow this group in the United States. Its nearly impossible to overwater Catasetinae during active growth! Most of the South American growers use the PET method, which is a very moisture retentive media concoction in a clear, plastic soda bottle with a water well at the bottom. This group loves water and fertilizer when growing!!

Mark Margolis (a well known Catasetinae grower and hybridizer from Florida) recently came and spoke to our OS about his breeding program. One of the more interesting things he mentioned is that Fred Clarke often doesn't start watering his plants until Memorial Day!! The new growths are large and kind of wilting, while the backbulbs are shriveled and sad looking. However, the new root system is HUGE and the plant fattens up very quickly when the water hits. Lets face it, Fred is probably the best grower of these guys in the country. So if in doubt about watering......don't!!! Wait a few weeks longer and your plants will benefit greatly.

[gngrhill]

Thank you all for your answers. Katrina, thanks for your step by step method, and thanks to all who clarify Fred Clark's method.

[fishmom]

I do know that Fred says that most root capacity is lost during the dormancy, but I have watered a bit when the back bulbs seemed overly shriveled, and then later when I was ready to repot I have found green growing tips. So maybe the old roots are not as effecient in taking up water and nutrients as they once were, but they still can function. For this reason I try not to damage them too much as I repot.