HELP! Oncidium/intergeneric emergency :(

[Princerobby]

About two months ago I purchased an intergeneric/oncidium from the store (I believe it was lowes) and the pseudobulbs seem completely shriveled

I bought it and it seemed healthy from the looks of he pseudobulbs. Not too many wrinkles so I thought it wouldn't be too much of a hassle to get them to plump back up again but things turned out much worse.

I'm fairly new to oncidiums and intergeneric but of all 4 I've been taking care of, this is the only one who seems to be struggling. It's actually the only orchid in general that I have that's struggling

Here's a rundown of the environment and how I care for it:
-Summertime here reaches around 85 on good days and 105 on the terrible days
-pretty arid
-I keep it in my house in front of an east facing window
-I repotted it because it was jam packed in a pot of sphagnum moss and soil
-it's new media is a fine grade bark with small bits of I think styrofoam
-I started off watering with unfertilized tap water once a week but then I noticed more wrinkles so I started going more frequently until I started watering every other day, while dumping the excess water (I keep it in a clear plastic pot with ventilation holes inside of a decorative pot)
-I cut off the flower spikes with a sterile scissors so they don't take away from the bulbs
-sometime during month 2 I started fertilizing with a 20-20-15 fertilizer to maybe help it with nutrients
-I give it a good soak in clean water at the end of the week to flush out any salts and chemicals
-the roots seemed fine. I unpotted it once to see if it was a root problem but they all seem ok, there's a lot more roots Than I thought there'd be and don't show any signs of root burn (unless I missed something)
-a few days ago I moved it out of the sun thinking maybe the heat was too much for it
-also the AC in my house doesn't work so it gets pretty warm in my room

I'm really worried about this one. I really liked the flowers on it and was really hoping it would last.

Is my orchid gonna die? >.<

[Optimist]

Oncidiums naturally grow in Arid places, however, the hybrids that are usually sold at Lowes and other mass consumption places are often a mix of warm and cool growing so that they are happy inside of a house.

Something that you say: that it is Arid and you live in about 85-105 temps (no winters?) makes me wonder if you are receiving water from a montane aquifer, or one of the great plains aquifers. If such is the case, your ph is probably 7 or above. Not that 7 is terrible, orchids like between 5.5 and 6.5 (thereabouts in general). A 7 ph means they are not getting the total amount of nutrients they need. There is a chart called "nutrient availability according to ph" which you should look at.

So, even if you are watering and giving nutrients, if your ph is wrong, they are not receiving the nutrients they need.

This is the same as my case: I also live in an arid area which has (warm season) about 85-105 temps, and in which I can keep every other orchid alive, except Oncidiums which shrivel and die in record time. I think the reason is the 7.0 ph that comes from the water hose. It is too alkaline.

Once the bulbs are shrivelled, I do not think they will just puff up again. It doesn't work that way. But if you can get the plant growing, it will have new growths that will eventually become mature and replace the old ones.

[rbarata]

There is a chart called "nutrient availability according to ph" which you should look at.

[Dollythehun]

Thanks rbarata. Very helpful.

[camille1585]

If it already had wrinkled pbulbs when you bought it, it's either than it was severely underwatered, or overwatered and the roots died off.

How were the roots? Firm and whitish (color may be various shades of brown also, depending on the potting medium) or very stringy looking? I ask this because I have no idea what your level of experience is, and many beginning growers have misidentified dead roots as healthy ones.

I have to say that at this point it seems pretty hopeless (not much encouraging signs of life). I personally would toss it and buy a new one. But if you do want to try to save it, I'd suggest repotting it into the small size pot the roots will comfortably fit (I have a sneaking suspicion that there are only a few good roots left), and keep it somewhere somewhat warm and bright, but with no direct sunlight.

While nutrient availability is important, that is at the bottom of your priorities right now (unless your tapwater is of very poor quality) and not the cause of this plant's problems. Fertilizing isn't even useful until you see some signs of new growth.

[Roberta]

Doesn't look great but not hopeless at all... It does need more moisture - the coarse mix will dry out fast. But if you can keep it watered, it may very well put out out new growth. With luck, the new growth will be established enough, with some roots, before it has totally exhausted the "supplies" in the old p-bulbs which will eventually totally shrivel. Wouldn't even worry about the water, as long as it's wet. (My city water is about pH 8, and I have been successfully growing orchids in it for 20+ years. Some picky rain forest plants need better water, but most of the ones in commercial trade like yours are much more tolerant)

[Ray]

Originally Posted by rbarata

While nobody can argue that proper pH can play a significant role in plant culture, this chart is something that might fit in the “urban legend” category. It may be a real representation of data collected in a study, but is actually of very little value to orchid growers, as it was derived from a single study, using a single formula of fertilizer, using a single SOIL substrate.

The fact that it is from a single study makes it somewhat suspect to begin with.

Not all minerals dissociate the same in aqueous solutions, and that can also be affected differently by pH. Do we know what minerals were in the tested fertilizer, their relative ratios and concentrations, and how they compare to what we use?

The fact that it is pour-through results from a soil substrate really confounds its value to orchid growers, as soils can have significant cation exchange capacities (CEC), while most orchid media have orders-of-magnitude less, if at all.

The cation exchange capacity is a measure of how well soil components hold onto positively-charged ions – cations – and most of the CEC occurs at the edges of clay particles and ultra-fine organic matter. The development of positive and negative charges on a clay particle is affected strongly by pH, so we can understand how, at extreme pH values, the charges may strongly bind the cations in fertilizer solutions, making them unavailable to the plants. In orchid media, which tend to have essentially no CEC, the nutrient cations tend to stay in solution and remain available.

The bottom line is that if it is in solution, it is available to orchids.

[rbarata]

All the graphics I've found, all have the same information.
Is there any suitable for orchids with, as you've mentioned, several studies and types of medium?
I would like to have that information.

[Ray]

Originally Posted by rbarata

All the graphics I've found, all have the same information.
Is there any suitable for orchids with, as you've mentioned, several studies and types of medium?
I would like to have that information.

I don't think any such information exists, because orchid media do almost nothing to sequester nutrient ions. Again, if it's in solution, it's available for uptake by the plant.

Let us not confuse this with the buildup of nutrient minerals (and plant wastes) in media, as that's simply a matter of the solutions becoming too concentrated as the water evaporates, so they precipitate and concentrate, ultimately reaching toxic levels. Fortunately, frequent flooding, coupled with a reasonable repotting strategy, allows us to "start fresh" periodically.

[Dollythehun]

Rbarata and Ray: I understand what you are saying about the scientific method of the chart. However, to my non-engineering mind, it gave me a visual of how certain nutrients might be effected. Therefore, the visual concept was helpful.😉