Yellowing phalaenopsis leaves and bud blast

[AEKass]

Hi all,

I moved to Northern California (Zone 9b) about a year ago, and have been struggling with where to keep my orchids. Currently, I have them on a piece of furniture that's in the middle of my apartment, with east and west facing windows on both sides of the apartment. I have two phalaenopsis and a cattleya on it. The apartment gets a lot of light, and because of the poor insulation the temperature varies significantly (in the summer it'll go from 60s in the AM to 80s in the afternoon). I think they are getting sufficient light, but sometimes the afternoon light seems a bit harsh. The cattleya is in really bad shape, it has no roots, but was like that when
I got it.

One phal seems totally fine, but the other might be struggling. And I am wondering if I could improve its health. The photos are of the one phal that is struggling. It has two branches, but all but one bud were lost to bud blast on one branch. There are two buds on the other branch, but I'm fairly certain they are not going to flower. Given the variance in temperature in the apartment I'm not sure I can prevent the bud blast. The plant also has two older leaves that are yellowing. I know it is common for older leaves to turn yellow and die, but I'm wondering if the number of yellowing leaves is unusual. In addition to these two, another older leaf on this plant turned yellow and died last month (I trimmed it off when it was fully dead). The roots seem healthy though.

Should I be doing anything different, or just let this orchid be?

[Roberta]

I think you are right, the temperature variation could very definitely cause bud blast. The yellowing of the old leaves probably force of nature. Or it could be getting too much light. (The Catt wants a lot more light than the Phals) It looks like it is a very open mix - which is great. (I'm guessing that you repotted it) But I wonder if could use more water. With an open mix like that that, it will dry out very fast - so may need the frequency of watering increased.

[Ray]

I also have to question if it's getting enough water.

The pot looks bone dry and none of the roots have green, growing tips, so I think not. The resorption of the leaves could be another indicator.

[estación seca]

I agree with Roberta and Ray.

That kind of temperature swing is great for Cattleyas and relatives - Anacheilum, Brassavola, Encyclia, Epidendrum, Laelia, Prosthechea, Sophronitis, hybrids. There are a lot of compact Catts being bred. If you get more orchids think about these.

Also, many Oncidiums and intergeneric hybrids should do well for you.

[AEKass]

Thank you all for the responses. I did repot it fairly recently--a few months ago.

I can try increasing the watering. I had been concerned over over watering as most of the post seems to retain moisture. The attached photos are of the same plant, but a better view of the pot. I have not watered it in about 4 days.

I got the cattleya in Feb or March, and all the roots were dried out and dead when I got it. I didn't realize it at the time though. I've been trying to revive it, but I've seen no new root growth.

[Roberta]

With regard to the Catt, just be patient... most have a very distinct rooting period. So if it is in fresh medium, it will very likely revive when it reaches the time when it wants to grow. I, and several other regular contributors to the Board, have found that Kelpmax can be quite helpful in getting some root action... worth a try.

[AEKass]

Thanks Roberta, I'll keep being patient with it! I have been using the kelpmax (once a month). Good to know it likely just needs more time.

[SouthPark]

AEK ----- do you have drainage holes at the bottom of your clear-plastic pot? I assume there are holes there - just can't see them that's all.

If you have good size drainage holes at the bottom, then also consider putting most of the water down the sides of the pot. Sort of like shown here ----- where the diagram shows scoria media, but it will be workable for your media too.

Click Here.

Don't focus on those exact details of the drawing. Also, the pot dish is for nothing more than to catch/gather any water that exits the pot during watering. And that collected water is just meant to disappear (after it evaporates).

And - even though nutrient and element deficiency don't appear to be an issue here ...... make sure to occasionally (eg. once a month or twice a month) ------ apply weak fertiliser and weak mag-cal treatment. Relatively weak application. Not strong.