Where do you have them in your home?

Mine are in this room which is getting heat from a 600 litre tropical fish tank and a 1000 watts room heater runs for a few hours in the early morning. The house is not centrally heated.

They are getting sun from a north facing window filtered by an outside blind and inside by matchstick blind. Current Temp where my Phals are is 19C (at 3:10 am)

Your plant doesn't look good, something is wrong with your growing spot and maybe you are

watering the plant incorrectly. Optimum temperature range 60 to 90F.

Here are culture notes prepared by the American Orchid Society.

AOS Culture notes

Thanks for responding Arthur:) Im looking through the link you sent now:)

Some more hopefully helpful info: They sit on my kitchen windowsill facing out to the garden, it gets lots of sunlight but its mostly indirect (south facing window). I'm in a very small bachelor flat so I only have 3 windows, 2 face the same direction (kitchen and bathroom) and one faces the side (east) but there's a tree so very little sun gets in. Currently the temperatures here are ranging from about 5'C to 25'C.

I've had 2 of the sick orchids for over a year and they've survived the last winter, they thrived throughout it and they were doing well this winter as well until about a week ago so I don't know what's changed between then and now as they've been sitting in the exact same spot the whole time.

I don't know if this bit of info helps but I have a fourth orchid that sits in the same spot and I water it the same way as the others and its not sick and the leaves are a reddish/purple colour which I've been told indicates a lot of sunlight? So I don't understand how one is doing well and the others aren't since they're living under the exact same conditions, which is one of the reasons I'm so worried about the other 3.

As for watering I've been told to immerse the roots in water for 2 minutes and then allow the pot to completely drain ( I leave them for 30 minutes in a drainer by the sink) so they aren't sitting in excess water and as it is winter I'm watering maybe every 2 weeks, depending on whether or not the bark is dry.

checked a compass to be sure of its direction and my window that the orchids have been sitting on for a year is in a SW direction

I'm with arthurm, something is wrong. I'm going to go with either a fungal or bacterial infection. Do you grow other plants in the same area? You are in S. Africa....how much actual sunlight do your plants get each day through that SW facing window?

I'm guessing, but I'm going to say you picked up an infection either from other plants in the vicinity, or from watering without sufficient sunlight. That may not be overwatering at any other time of the year, but with minimum sunlight, your past normal may now have been too much.

Your photo #3. I agree the dark spot looks like the same infection starting there too. I'm more worried that the base of that leaf at the top of the photo looks dark to me, like maybe its down in the crown there. If not, I would take a sterile razor and cut that leaf off below the dark spot. Be sure you get back to healthy tissue, and apply a fungicide to the cut, and keep the leaf dry until it tells you what its going to do.

I'm afraid I can't offer much encouragement....Bacterial and fungal problems are airborne, that's why it hit so fast. Your small apartment probably with minimal air flow did not help either. Once those things hit you have to be on top of the problem immediately with some pretty radical measures to stop it from spreading. Get those bad plants isolated, and try to save the one that is not as bad. Good luck.

Bil

Dawn! Another day in the "Sub Tropics" where most members of the local Orchid Society regard Phalaenopsis as difficult.

Those fungal and bacterial infections that Bill is talking about strike when growing conditions are not good. Have to agree with Bill about the treatment, if the plants get those sort of infections they go downhill fast.

Looked up the weather for Pretoria and today here will be almost like there. Min 6 max 19C and sunny.

Phalaenopsis are warmth hogs, they might be better in nice centrally heated home in Northern USA.

You might need a heat pad or light to warm the plants up a bit to get through winter if the temps in your apartment are on the low side.

Watering has to match up with the potting mix, temperatures , air movement and so on and it is the most difficult part of orchid growing to get right. Mine are being watered once a week in winter. When they were out in a glass-house in summer (near the floor in heavy shade) they were watered with the hose every two or three days.

Slight redness of leaves is probably OK. 3 of my collection of 7 plants have reddish tones on the leaves. Avoid direct sunlight.

Sorry, cannot offer instant cure.

Thank you both for your answers!

Bill thanks for the advice, I have followed it as much a possible right now.

I am not sure how to measure the sunlight coming in through that window but I would say its a decent amount, medium lighting, I'm basing this on the fact that the lighting is not nearly as poor as in the rest of the flat, its fairly bright but not so that the sun is glaring in, I think if there was much more sunlight coming in it would burn my plants during summer (its very hot and sunny here generally). the washing line is situated in that part of the garden that the SW window faces out to and the clothing dries fairly quickly, however this week I would say less than usual sunlight as the weather has been overcast.

I have to agree that poor airflow is a factor, now that that has been mentioned I see that it could definitely contribute as my windows have been closed at night and whenever I go out lately (due to crime in the area increasing).

I'll do some research, find out exactly how I should be watering this time of year here in SA and alter my watering schedule and method and try get more airflow in. In the mean time I have taken your advice and removed the infected leaves and until I can get to a nursery to buy the right treatment for the orchids I have applied cinnamon to all the open wounds.

Arthur I will take your advice and get some extra lighting or a heating pad and change how I water the plants. I would like to thank you for the link, I looked around the American Orchid Societys website after reading through the page on orchid care (which was very helpful, it elaborates more so than my book on orchid care does so I have a much better understanding of what I should be doing) and found a section about sick plants, I went from there to a few other sites to double check and back up what I thought it might be. Based on that research I have to agree with both of you that it seems to be a fungal infection (apparently bacterial infections come with a smell and mine don't smell bad at all - even the very sick orchid still smells okay) and it looks like it is causing cell death in the leaves and stems of my orchids. I couldn't find the exact infection but I saw quite a few that looked similar and they all seemed to be associated with cell collapse and death leaving ugly spots on the leaves.

I'm going to look around for a better spot to keep them in and I've isolated the sick orchids so long. I'm hoping that by following your advice and keeping an eye on them that they'll return to full health, I'm not sure my newest orchid will, she looks a bit too far gone but I'm going to try anyway - I've never given up on an orchid yet and none have died ever died on me yet so I'm holding thumbs. Thank you both once again, I've been in a bit of a panic so receiving advice and information has gone a long way to helping me calm down enough to form a plan of action. If they survive I'll update this post with the healthy orchids:)

I just have one last quick question, all three sick orchids have stems/spikes. My two older orchids are forming new ones, they're busy growing (about 3cm in length so far) and the newest and sickest orchid has two fully grown stems and the flowers have died (presumably due to the infection) but the stems are still alive - they have not dried out and gone brown. I know that these can sap a lot of energy from the plant. Would you advise removing them to assist with the healing process? or should I leave the growing spikes and hope that it doesn't affect the plants ability to recover

Okay ill cut them all timorow, Im sad to lose my new spikes cause theyll only spike again next year but at the same time its more important that the orchids make it to next year! I dont think orchid 1 will though, she only has two leaves left and I noticed rotting on the ends of the leaves today so Ive cut them but if it keeps up she'll have no leaves left, I think shes spreading the infection so shes seperate from the other sick ones now as well. Im struggling to keep up with how quickly its spreading, everyday theres new rot despite the cinnamon and fungicide. The others arent showing signs of new infection though thank goodness!

I think I understand what you mean, it makes sense that the pot would feel colder and heavier when wet so I'll definitely give it a shot, its much better than guessing that the plants are dry, I have an empty pot with mix in so I'll water that too and check it while I practice. The hefting sounds similar to picking a child up and pretending to throw them up into the air when playing so I think i have an idea of what the movement should look like, I'll give it a try in the morning. I really appreciate the tip thank you!