Help with odontoglossum

[orchid_fan]

I'm hoping someone can offer some advice for my problem with a NOID odontoglossum. The pseudobulb has shrivelled significantly within the last 3 weeks, to the point that it's almost flat. The leaves still look healthy, but 2 new shoots on the side have stopped growing. (They actually stopped growing over 6 weeks ago.) I recently repotted this plant and checked the roots thoroughly. They looked good and were not rotting. I water the plant every 6 days, as I've always had, and the temperature has remained relatively stable (around 70-80 degrees). Any ideas as to what's causing the psedobulbs to flatten? Am I over/under watering? Is the plant in a resting stage? Have I killed it?

[PAGrower]

I think you might be underwatering, but before going ahead and drenching the plant I would stick a wooden stake (toothpick, Q-Tip) into the medium and see what comes out. Did you switch mediums when you repotted, by any chance?

[LJA]

Nancy, I think PAGrower's right. PBs will shrink some as new growth sprouts and develops, but it shouldn't be so drastic in such short a time.

Also, make sure your temps are really staying at that mid 70s level. Summer's kicking in, and Odontoglossums really need to stay cool.

[orchid_fan]

Did you switch mediums when you repotted, by any chance?

Hi PAGrower,

Nope...I'm still using fine bark which is what it was previously potted in. Do you think a good soak would help rejuvenate the bulbs?

[PAGrower]

Nancy, assuming you checked the medium and your 'dipstick' came out dry, I would give it a good soak. I've sometimes read that shriveled bulbs can't be rehydrated but I have had some success, at least with Catts. It takes time and they don't end up being completely smooth, but you can plump them up somewhat. I've never tried to resuscitate an odontoglossum bulb, though.

If you move the plant to a cooler spot as lja suggested, you might be able to get away with watering it every 6 days, but I would check it for dryness every three days or so until you get a handle on how quickly the medium is drying out.

[orchid_fan]

Hi PAGrower,

Thanks, I'll take your suggestion and move the plant closer to an open window so it can benefit from the breeze and cooler air. I did indeed use the "dipstick" method you recommended, and the Q-tip I inserted came out with barely any dampness. It's been 4 days since I watered so I will continue checking the medium and adjust my watering accordingly. I don't mind if the pseudobulb doesn't plump back to its natural state, as long as the plant can continue to flower and grow. Do you think this will be possible, even with a shrivelled bulb? Thanks!

[PAGrower]

Nancy,

If the plant only has the one pseudobulb to sustain it, you might want to give it the ailing orchid treatment for a little while. Cutting back the light a bit and skipping the fertilizer may help until it starts growing again. Hopefully, lja will jump in with second opinion here because odontoglossums are tricky to grow, for me at least, and I would totally hate to steer you in the wrong direction.

[LJA]

Ok, jumping in.....

PAGrower, everything you've said is right on, as far as I'm concerned. Nancy, the only thing I wouldn't do is try to make that pseudobulb swell up again. It's a pretty good bet that it never will, and at this point, if you use its plumpness as a gauge, you're more than likely going to end up overwatering, trying to puff it up. Hold back for a couple weeks on the fertilizer, keep the plant cool, and water when the middle of the root zone has dried to dampness. If the Q-tip comes out just barely damp, water the plant. The new shoots will resume their growth and you should have no problem spiking them in about 4 or 5 months' time.

[momokev]

I'm gonna add my 2 cents worth In my orchid society, there is a very respected, long time grower. She grows everything in the oncidium alliance in sphagnum moss. Because of her, I am changing mine over as I repot. I am having very good success with this, and I really like that all you do is wait until the top is "crusty" to know when to water. I have a Bllra Peggy Ruth Carpenter 'Morning Joy' that I repotted yesterday that has been in sphagnum moss for a year, and there was not one rotted root! It has 2 new growths and is a very happy camper. I think it's gonna be the way I go for sure, since that plant did so well. Draw back is the yearly repotting, but I can live with it.

I had a problem with underwatering. I read the books and they all said "water once a week" and "let the roots dry out" It took killing my silver chalice with underwatering (which did the same thing as yours, by the way) before I realized what I was doing. The sphag has solved that problem for me.

Lisa

[PAGrower]

Cool growers in general intimidate me, probably because I've killed a couple. Given where I live, people always assume they should be a piece of cake. Gah!