Crusty growth on Oncidium pseudobulbs

[roses1982]

Hi, I have started noticing greenish white crusty growth on my Oncidium pseudobulbs and leaves. They are on old and new bulbs. Initially I thought it was fertilizer deposit but maybe not. Anyone know what they are and how to deal with them?

[estación seca]

The photo is a little fuzzy - it could be mineral buildup from minerals in your water. It could also be mealybugs, though I don't think so, because that isn't where they usually attack orchids.

Are you using tap water?

[roses1982]

Yes, when I water with plain water, I let tap water run through the medium. You think that could be the issue? I'll try using filtered water from now on.

[estación seca]

If you get water from other than a well, your water provider posts their annual water quality report on their Web site. You can look it up and download it. Water for orchids should have relatively low total dissolved solids, TDS (which are mostly calcium and magnesium salts) and a pH near neutral. A lot of municipal water is alkaline, near pH 8.

Different filters remove different things. People save rain water for orchids. The next best thing is reverse osmosis purified.

[silken]

It looks like mineral build up from what I can tell on the photo. But I have had immature scale start down at the base and in between growths on an Oncidium. It looks more white and fuzzy tho and no brown, so I don't think that would be it.

[My Green Pets]

It looks like you might want to water more often, the pseudobulbs seem shriveled. Perhaps more frequent watering could flush those mineral deposits.

[Orchid Whisperer]

It could be mealy bugs, can't tell from photo. Look over the plant closely with a magnifying glass of some kind.

As far as the dryness I would give the plan a brief soak when you water. 15 minute soak each time. When warm enough, leave the plant out in a soaking rain.