First, the normal pattern for leaf growth is for the bottom leaf to die and be replaced by a new leaf on top. This is likely not related to bud blast.

I am wondering about the air temperature and the light level. Humidity is less likely to be the problem. You didn't mention what state you live in.

Phals like conditions similar to African Violets.

As richardol said, not to worry about the leaf.

The buds however could be a few things. Air temperature, yes, and even more specifically changes in air temp.

If this is a new Phal. you bought at a store and brought home, the change of environment (or if you live in a cold state like I do the big drop in temp. on the way to the car) could be enough to cause bud blast.

Another source of temp fluctuation is your window, maybe place a thermometer to see how much fluctuation occurs.

Also of course light, depending where you live it may not be getting enough, phals. take a lot more light than their labeling tends to imply.

As was implied, the cause is most likely the drop in temperature at night which is causing moisture trapped within the tissues of the bud to condense, leading to bug blast. Try to keep the temps more stable and avoid drafts and you'll probably see better success. Also, a watched pot never boils. Stop watching it and they'll probably open no problem.

Hi thanks for all the input! To answer some questions I live in Southern California. It's about high 50s and low 60s in the morning and night. During the day it can go from anywhere between 70s to mid 80s. The window I have placed the orchid next to is a W facing window, so there is plenty of sunlight and I get maybe 2-3 hours of direct sunlight in the late afternoon (of course the phal never gets direct sunlight).

I'm not sure if my orchid is just dropping its buds because it is new and I've brought it home, since it was fine for a month and a half before any changes started happening. I'm new to orchids so I have no idea if thats normal or not.

Since the weather where I'm at is generally warm and dry I had thought that maybe it was not enough humidity. Any other ideas? I think I'm going to move it slightly further away from the window as it tends to be colder at night near the window.

Thanks again for all the help!!!

Actually I would suggest that you move it closer to the window! Orchids love sunlight - those 2-3 hours of direct afternooon sun would be perfect for your phal. Of course, only migrate your phal slowly (1-2 weeks) closer to your window so that it has a chance to acclimate to its new surroundings. If you touch the leaves and feel that they are hot, move the phal back a little and give it some more time to adjust. To get the best growth and blooms you want to give it as much light as it can handle.

From your second description (and I might have misread it) it sounds like your flowers that have been open for 1.5 months have yellowed? If this is the case, that's probably normal - just the lifecycle of the flowers, not bud blast. Bud blast is when immature buds (not open) die before they mature and open. As Richard said, the bottom leaf dying is normal too. To me it sounds like you're taking care of the orchid pretty well.
Best,
~Jem

I think mrbreeze nailed it. Except maybe the part about not watching. Who can do that??

John :>)

Being that there is not snow outside your window, I would agree the closer you are to that window the better, as long as the leaves do not feel hot then it should be fine.

As already stated move it closer slowly.

My guess after hearing what your conditions are is that the buds actually began the "blasting" process before you ever looked at if, probably en rout to the store you bought it at. Sudden climate changes don't help buds at all.

On the upside, the plant does not sound like it is in trouble so it should give you something to look forward to when the next growth is all mature.

Hi Mini,

I live in a part of California with a climate similar to yours at this time of year--low humidity, day to night temp range (indoors at the window) of 60 to 85. My Phals are in an ESE exposure, and screened from most of their direct morning sun by a semisheer curtain. They get no direct afternoon sun. They have had winter-spring conditions like these for three years and seem to "like" them just fine, so I doubt that your conditions are the direct problem.

You have had the plant long enough for it to have made the adjustment from store to its new home. I'm guessing that John (aerides), in his first post above, is correct and the difficulty has to do with the watering of your plant. Knowing when to water is probably the trickiest part of learning to care for a Phal.

If one waters too soon, the plant stays wet too long and is subject to rot. If one waters too late (i.e. after the media dries out) the plant selectively economizes, reducing water to some other of its parts, resulting in a desiccated leaf, wilting flowers, or blasted buds.

Being at an open window can accelerate the drying of your plant. Since sunlight, temp, and humidity fluctuate, watering once a week will not always be enough, and sometimes it will be too much. The good news is that you can check.

If you gently work your finger down about two inches or so into the media and it feels damp, then your Phal does not need water. If it feels barely moist, then it IS time to water. You do not want it to dry out completely, because (as John also pointed out) the flowers or buds will be the first parts to suffer.

Some growers can tell if their Phals need water by lifting the pots: if they are light, they need water. But this takes a sensitive touch and a bit of experience to learn. Others use a rounded off skewer buried 2-3 inches into the media. They pull it out, touch the tip to their lip or cheek, and if it is cool or damp they don't water. Both of these are a little too subtle for me, so I use the finger method.

This post may be a little too late for the saving of your blooms, but watering technique is something that you will need to keep your Phal healthy after blooming, as well. I hope it will help, and that your next blooms will give you their full complement of three or more months of joy.

Sweetcicely

Thanks for everyones help!

Well when I bought my orchid there were three open blooms, and a lot of unopened buds. After a month and a half the blooms started wilting, and I figured that is probably normal for flowers to drop. Soon after that all the unopened buds started dropping and now there are only three half opened buds left.

I think it might be a water problem. I had been watering it once a week because I was worried I would over water my orchid. It's been sitting next to a window all this time and I keep my window open sometimes. On top of that, the weather has been slowly growing warmer.

I'll try to keep a closer watch on the watering level and hope for the best.

Thanks again!