Notes from Fred Clarke - Orchid Board

Roberta · #1 09-11-2018, 03:02 PM

There are lots of questions about watering/fertilizing of Catasetinae, especially at the "edges" of the seasons. I get Fred Clarke's email newsletter (Sunset Valley Orchids), notes which I think are worth sharing.

------------------------------
From Fred Clarke:

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

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.

Now is the time when your Catasetinae can really take advantage of lots of light and air movement to help 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%.

It's still important to keep an eye out for those pesky spider mites. These can really 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!

Looking ahead, autumn is just about to start, and that means winter will be upon us soon. Yeah, I know, it arrives faster every year. We are still about two months from the time that you should 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 plant culture will cause the pseudobulbs to harden off, in preparation for dormancy.

camille1585 · #2 09-11-2018, 03:35 PM

Thanks for sharing! This is my first year with Cats, and I need all the pointers I can get.

estación seca · #3 09-12-2018, 01:14 AM

I can't remember the person's username, but a member from Germany (I think) posted photos of his greenhouse and discussed attempts to keep nights warm enough for Catasetinae to be happy. He said outdoors even in summer wasn't warm enough at night.

Regelian · #4 09-12-2018, 04:53 AM

Camille, as we have almost the same conditions (Cologne), I found this last Summer very difficult for all my orchids. Too hot, lots of sun, but extremely dry air. We went 3 months with NO rain and day temps around 30°C+, nights around 25°C in Cologne. Many of my Catasetum did not want to make roots, as there was little moisture in the air, despite humidifyer. As it cooled in the last couple of weeks I am seeing massive root growth on many , which had otherwise remained almost dormant through the Summer. My main problem was the excessive heat. In order to cool the greenhouse, the roof windows were always open and humidity rarely stayed above 20%. Of course, this is a problem, and the light is going at this point. I am removing my shade cloth this weekend, to increase light and plan to move a few to an indoor window (south facing) to help developing spikes (yeah, some are coming despite small growths). Hope I do not shock them.
In the end, this Summer was an exception in all respects and should not be used as a norm for Catasetum culture. Last year was considerably moister and, although less sunny and much cooler, altogether easier for orchid culture. Adding heat, water is easier than cooling and maintaining high humidity. Interestingly, my Cattleyas all did very well, as they really like drying between waterings, which I find Catasetum does not relish. Once in full growth they want moisture 24-7.
In the end, I learned a great deal this season. Chalk it up to experience.
Jamie

camille1585 · #5 09-12-2018, 06:06 AM

We also went 3 months with no rain, and extreme heat in July through to mid August. I kept my 2 Cats indoors all summer. I put them in a south facing window instead, one did very well, with tons of root/shoot growth. I did notice a slow down in growth during the absolute hottest weeks, where even my living room was at 34C, and often over 30C at night... and the new bulb is now larger (by at least 30% I'd say) than the previous one. I also struggled with low humidity and had to water part of the collection twice a day.

The second plant did not do so well. It's a Clo. Rebecca Northen and it started growing much, much later than the other plant and with the heat it just struggled to get going since it didn't yet have a strong healthy growth like the other plant . The bulb is still barely developed, and is less than a quarter of the size of the old one. I'm not sure it will recover, and I wonder how it will grow next year, without that bulb for reserves. I don't think my culture was the problem seeing as the other one did extremely well.

jcec1 · #6 09-12-2018, 07:40 AM

Quote:

Originally Posted by camille1585

We also went 3 months with no rain, and extreme heat in July through to mid August. I kept my 2 Cats indoors all summer. I put them in a south facing window instead, one did very well, with tons of root/shoot growth. I did notice a slow down in growth during the absolute hottest weeks, where even my living room was at 34C, and often over 30C at night... and the new bulb is now larger (by at least 30% I'd say) than the previous one. I also struggled with low humidity and had to water part of the collection twice a day.

The second plant did not do so well. It's a Clo. Rebecca Northen and it started growing much, much later than the other plant and with the heat it just struggled to get going since it didn't yet have a strong healthy growth like the other plant . The bulb is still barely developed, and is less than a quarter of the size of the old one. I'm not sure it will recover, and I wonder how it will grow next year, without that bulb for reserves. I don't think my culture was the problem seeing as the other one did extremely well.

I received two small catasetums last year - the pseudobulbs were fingernail sized -, they were horribly infested with red spider mite, then in October they both produced new growths. Contrary to popular advice I watered them both throughout winter, the new growths continued growing and the plants suffered no rot - so if you feel brave you could lightly water the plant throughout winter to maintain growth.

One of the plants is now spiking so I don't think it had any ill effects on it.

isurus79 · #7 09-13-2018, 09:21 AM

Quote:

Originally Posted by Regelian

We went 3 months with NO rain and day temps around 30°C+, nights around 25°C in Cologne.

Sounds like spring or autimn here in Texas! I go for many months in summer with temperatures approaching 40 degrees C and my Catasetinae and Cattleyas love it! I grow them outside so they are exposed to the full heat all summer. I water daily and they have massive root balls!

Heat isn't a problem for these guys. You just have to increase the water frequency.

Roberta · #8 09-13-2018, 11:12 AM

Rain? That comes out of the end of a hose, right? If I had to depend on the natural variety, I'd kill cactus...I think the last time I saw the stuff that comes out the sky was last February...

malteseproverb · #9 09-16-2018, 03:26 PM

I have a cat with Clo. Rebecca Northen as a parent and also faced 35C temps with no rain for weeks this summer in Northeastern US. My other cats swelled up quickly but this one definitely lagged behind, but it also started growing later. Now it is looking fine. Lots of roots, and the two pbulbs it's putting out and finally approaching the size of last year's growth (which was only one pbulb). However the leaves are smaller, but it might be because I chose to grow it in full sun this year rather than much shadier indirect outdoor light. We'll see if it blooms as spectacularly as it did last winter but I'm getting the sense that it's a bit slow to start in general but catches up eventually.