My phalaenopsis orchids are turning yellow and dying suddenly
 

Hi,

I have purchased several orchids in the last 7 months. Since February, the climate in my town has turned very hot and dry. I water the orchids every alternate day. While the cattelya, dendrobium and other orchids are healthy and growing new shoots, my phalaenopsis leaves are suddenly turning yellow, the roots are dring and the plants die within a week. I have checked that there is no root rot. I am growing them indoors and have installed led lights along with sunlight. Today I placed a humidifier too.

Please check the photos and advise what is wrong.

Thanks

First of all, welcome to the board, Supernic!:)

If you mean those two bottom leaves in the 2nd photo, those are old leaves and it's perfectly normal as they are not meant to live forever.;)

Welcome to the Orchid Board.

Phals. don't need as much light as do Cattleyas. Excess light leads to fewer and smaller flowers. They will be fine in a window without direct sun on their leaves. Save the lights for the high-light plants.

Phals. in a lower humidity house carry fewer leaves than in a humid greenhouse. The Phals. inside my house, which is usually in the 30s C during summer with 30%-40% relative humidity, carry 3-4 leaves. Those in the sunroom with 60%+ humidity may have 6-10 leaves.

Thanks for your responses, but there is one which had 5 leaves and 2 spikes but just died. And another which lost 3 leaves in 2 days. I am sharing the pics.The one with 2 leaves remaining was potted in coconut husk. I repotted it in moss today. Compare them with the healthy cattelya, Anoectochilus and catasetum orchids.

hmm, well our conditions are completely different than yours so our comments are worth less than an swiss penny. however, in super dry conditions you may find it tricky to grow phals in moss. once the moss dries, it is tricky to get hydrated again. perhaps that was part of your problem?

also, as mentioned, if you had them in a bright window and had them under lights then perhaps it was too much light and heat for them?

final thought, is that we have had a couple orchids die from what only we call SODS, sudden orchid death syndrome. others we have seen online have had this problem. i have no idea what can cause it, but yeah sometimes a healthy phal will drop all leaves very rapidly and die. this seems quite rare, so for it to happen to 2 plants at the same time makes me think it is more something in your conditions.

well, dump those pots out and go shopping for a cheap phal or two to do some testing on! don't give up!

There is a disease called collar rot. Look at the diseases section of the St. Augustine Orchid Society Web page.