Yellowing Leaves

[eaglssong]

I know there are other threads regarding the yellowing of leaves, but frankly, I'm too lazy to go hunt them up, but I'm starting to get really concerned. A few days ago, I mentioned that my Zygo had a yellow leaf, and I was advised not to worry, but that it would come off. Well, today it did that, and that was fine, because I expected it, and the rest of the plant looks just fine. Well, today I also noticed that I have others that now have yellow leaves on them, including the one that had a spike showing thru the sheath in a backlight condition.



Is it possible that it's just too warm for them out there? It does get pretty warm and humid at night, and although I have a fan going, it's not very strong. Should I turn on the a/c out there at night? Or (perish the thought), is there something more serious afoot here. I don't exactly like the way this one looks, with that big black area, but these plants had been outdoors originally, and had signs of sunburn, so I wasn't too concerned at the time. Should I be worried now?



Except for this awful heat we've been having (which of course is normal for here), everything is basically the same. I mist daily, and water as needed.

[Brutal_Dreamer]

Top photo is bud blast on that cattleya. The bottom photo is sunburn. If you are misiting, don't do so in the hot of the day. The water drops will act like magnifying lenses and increase the heat to the plant. Mist in the early morning and keep the fan running. If the sunburn is 'new' then you have some direct sun-light hitting this plant and need to move it away or filter it through some sheers or shade cloth.

The bud could have blasted from many different things. Humidity is the most likely the problem, but it could be something else. Usually this happen when there is not enough humidity. JMHO

Cheers,
BD

[eaglssong]

Thanks Bruce. Somehow, I don't think lack of humidity is a problem here. And when I mist, I always mist in the morning.

If it was just one yellow leaf, on one plant, I wouldn't be so bothered, but obviously there's something that's causing this, so I'm going to keep a close watch on the conditions. If I have to move them to a different room, I will. I'm pretty sure that's old sunburn too, because even though the windows behind them are south facing, any sun is generally filtered pretty well because of the trees outside, and the solar film on the windows.

I'm so disappointed about that sheath/bud blast. Hopefully, that orchid will decide to try another one and reward me with some gorgeous flowers.

I turned the a/c on there a few hours ago. Don't think I'll run it all night, but hopefully that's got the room cooled down a little bit for them.

Boy, this hobby of ours sure does get frustrating sometimes, doesn't it?

[Brutal_Dreamer]

Be careful with the AC. Make sure not to have it blow directly on the orchids. The AC will remove the moisture from the air to cool the room. This will mean that you will need to adjust your misting/watering schedule to balance the humidity reduction.

Bud blast happens, Anne. It probably is nothing you did. I would not be too worried by a few yellow leaves. The sheath that blasted turned yellow after the buds died. This hobby of ours does get frustrating, but remember the joy it brings when the blooms come and all is good again. That frustration seems to just float away.

Cheers,
BD

[eaglssong]

Bruce, you have such a talent for making me feel better. Thank you my friend.

So, now that we've decided it's bud blast, do I remove the sheath and the spike that was forming? Or do I just leave it alone and let it fall off when it decides to do so? I suspect the answer will be to just leave it alone, but amazingly, I've never had any buds blast before, so I'm not 100% sure.

As for the a/c, the one out there is ancient, and while I ran it a bit last night, it really didn't do much to cool down the room, so what I did instead was to leave the sliders open, so that some residual a/c from the living areas would seep out there, and this morning, the room was quite comfortable. Not cold by any means, but not all hot and steamy too. I think I'm going to try it this way for awhile, and I'll just watch the watering and misting and make adjustments as needed. Besides, don't we get better blooming if the night temps are somewhat lower than daytime temps?

And will I ever run out of questions for you guys?

[Brutal_Dreamer]

hehehe... I would let it fall off when it is dry to avoid opening up the area to infection. With AC and a really humid room, something I foud-out last week from our AC repair guy is: if you have a really humid and hot space, it will take several hours to cool the space. The air conditioner will have to first dry the space out by removing the moisture from the air, carpet, curtains, furniture, etc... and then it can actually start to cool the space.

My two nieces, nephew, and my mom were coming to visit this past week and I needed to get the air conditioner for the upstairs of our house working. I called the AC guy and he put in 14 pbs of freon (coolant) into the unit outside. (Apparently there is a very slow leak that takes about two years to suck all of the coolant out.) Anyway, after running the unit for about 5 hours, I called him and said it was still 80+ degrees upstairs and he told me that to wait until the next day because the unit first had to dry out the space then it could cool it. He was correct. By the next day, the space was comfortable and cool.

To answer your question about temp drop and better blooms: Some orchids require a 10+ degree temp difference between day and night to even produce blooms. Others like to have a day time temp at one level and a cooler night time temp. All are a bit different. I don't feel having a temperature difference will hurt your orchids in any way, but it may not help all of them either. It is really up to you.

I hope you don't run out of questions!! You always have really good ones that require thought and consideration. I am sure many people now and in the future will appreciate your questions and the answers you get from the growers here.

Cheers,
BD

[Ron-NY]

I have seen bud blast from air conditioning ...too bad...I am sure it will bloom for you on the next growth

[eaglssong]

Thanks Ron. That blast wasn't from the a/c, as I hadn't been using it. I suspect the room was actually too warm. We'd been running in the 90s every day, and while I had the fan on, I don't think the air was moving enough. I now have a stronger fan out there again, and hopefully, things will settle down.

Right now, I'm not seeing any more yellowing leaves, but I'm watching like a hawk.