humidity high water low after repotting to promote roots?

[nogreenthumbs]

Originally Posted by estación seca

First, were all three photos taken at the same time? One photo shows two swelling eyes, which grow to form new growths. I don't see the longer growths on this photo. The other two photos show elongating growths, which could be those two eyes some months later.

All of the posted photos were taken about 5-10 mins before I posted. The two longer growths are on one side, the shorter growths are on the other side.

The left elongating growth looks healthy, but the one on the right is turning black at the tip.

The coloration of the longer new growth is more of a red/purple/wine color in person, which may not have come out well in the photos, but you have much more experience and knowledge than I do so you're probably correct. The small new growth does however appear to be turning black at the tip. Since I've got 2 growths from the winter and 2 more than are almost 1" long, and the plants got sad roots, I'm not concerned with having another new growth abort. That's probably a good thing in the grand scheme so the plant isn't trying to create the new growth and can maybe direct that energy into root production, wouldn't you say?

This is often caused by insufficient water, which in turn can be caused by not watering enough, or by having a sick root system. Some people say extra calcium prevents this, but your plant's problem is roots, not calcium. That new growth will probably die back completely. There is a chance only the tip will die, leaving a stunted growth. Fortunately such a stunted growth would probably have growing points, which have the potential to make completely normal growths, with proper care.

I tried to do what is recommended by letting the media completely dry between waterings but it was difficult to be certain since the pot was black plastic and the media seemed old when I repotted. I was watering about once a week in an environment the AC running which is usually pretty dry. I was fertilizing (as the seller advised) with balanced Osmocote. I noticed before repotting a buildup of salts on some media at the top of the pot. There may have been a watering (most likely over if anything) but I also think excess fertilizer was a factor.

Most Cattleyas make new roots as new growths are elongating. Yours doesn't seem to be doing this. It is possible it is one of the ones that makes new roots only after growths mature. Cattleya warsczewiczii is one such plant. This kind of plant needs careful attention not to kill the old roots before growths mature, because the plant will then not be able to take up enough water to support new growths.

It's possible fertilizer burn killed the roots, but more likely is that you overwatered the plant during the cooler winter, and the roots rotted. Or you underwatered as previous new roots were forming, and killed them before they got big enough. Or the plant had poor roots when you bought it. When the roots aren't good, or you don't water a healthy plant enough, new growths are smaller than previous growths.

Cattleyas won't make roots until they decide it's the right time in their growth cycle. Humidity has nothing to do with it. The high humidity is not to induce roots, but to decrease water loss from the leaves until new roots form.

I looked at the plant in better light just now. I see what appears to be small bumps very low on the growths from last fall. Hopefully, those will be roots.

Thanks. I guess I'll do what I can and wait and see.

---------- Post added at 07:28 AM ---------- Previous post was at 07:24 AM ----------

Originally Posted by King_of_orchid_growing:)

Have you seen my Huntleya wallisii? The humidity is around 92% in the dart frog tank I have it in. Granted it does have good roots inside the basket, and it is a plant that does like quite a bit of moisture, so keeping the media dry doesn't really apply to my Huntleya, but notice that the roots growing in the air are growing like CRAZY!

The roots have grown about 1" in about 2 weeks!!! If the humidity was even 17% - 27% lower, those roots would not grow like that.

You want evidence, that's your evidence. I posted that for a reason. I wanted people to understand the power of controlling humidity for certain orchids.

Your Lc is not the same as a Huntleya, but the basic principle is similar. Jack up that humidity, and you will get the plants to produce roots, especially during growing season.

These are grown indoors with the AC running most of the time, but the missus does like to open the windows in the evenings so the humidity is not as low as it would normally be when the AC is always running. It has been very humid here lately. I do have them sitting on humidity trays as well. I guess I could try a sphag and bag approach.

---------- Post added at 07:39 AM ---------- Previous post was at 07:28 AM ----------

You guys missed one of the main points of my question.

Should I try to create an artificially humid environment (assuming I can't just put it in a naturally humid one) AND stop watering? Or should I continue to water (allowing to dry between waterings)?