Need care tips! Onc. Space Mine Red Rendezvous and Onc. Rex's Luck Firefly

[sweetas647]

Hi all!

I just purchased two young (2-3 years old?) Oncidium hybrids - Space Mine Red Rendezvous and Rex's Luck Firefly. I'm super excited about them but want to be sure I'm giving them what they need - especially with them being so little!

They are currently potted in bark chips with a sponge/bit of foam around the roots. Each has one very small and pretty wrinkled pseudobulb. I've watered them the past two days I've had them with distilled water and they are sitting in a south facing window.

Does that sound right? Should I fertilize them? What humidity do they like?

Any insight is much appreciated!!

[Roberta]

First, Welcome!

Photos would really help. If you have trouble posting, you may need a few more posts (like 5 total) before you can post photos... but I have seen photos from new members with fewer, so worth a try. There is a sticky with detailed instructions.

If the pseudobulbs are wrinkled, the plant is probably dehydrated - but there are two possible reasons. The easy one is that it just didn't get watered enough while waiting to be sold. However, the other possibility is that roots are rotted so that they can't take up water. To figure out which is the cause, you'll need to take the plant out of the pot and have a look at the roots. I have found that newly-acquired plants usually do need repotting. Again, photos will help other board members to help you. Unless you are in a super-dry area, house humidity is probably OK (especially this time of year when you won't have the heater dropping the humidity)

With regard to fertilizer... of all of the cultural needs of orchids, that is the smallest factor. Orchids are really light feeders, since they grow slowly. Think of fertilizer as vitamins, not food. So let's get everything else right first, then look at options. But pretty much, it doesn't make a lot of difference what you choose, the important thing is to use just a bit - like whatever it says on the bottle, use 1/4 to 1/2 as much. "Once weekly, weakly" ... or even every other week. Too little fertilizer, and the plant may grow more slowly. Too much, on the other hand, can be fatal. So err on the low side.

[estación seca]

Welcome to the Orchid Board!

Oncidiums have thinner leaves and roots than many other orchids. This is an indicator they need more water than some other orchids. However, they don't like soggy, airless potting media. Are the bark chips large or small? Do there seem to be generous air spaces between the chips?

They do well with less light than some other orchids. You don't say where you live, but if your south window gets any sun and heats up, it's probably too bright and hot for most orchid seedlings.

I keep small Oncidium plants in bright indirect light. On the other side of a sheer curtain works for many people, or in the bright area near a window where direct sun doesn't fall.

As Roberta mentioned, their pseudobulbs should not be wrinkled. If the roots are healthy, watering every other day in a south window might not be enough, particularly if they were shipped dry.

[sweetas647]

Thank you for the tips! I've attached some pictures of the little guys.

I have been watering them everyday with distilled water since receiving them. The larger of the two is the Space Mine and the pseudobulb does look a bit plumper but no noticeable change in the Firefly.

I do live in a dry, pretty warm area... may need to invest in a humidifier.

[SouthPark]

Does your orchid pot have holes down the bottom of it for drainage?

Also - make sure to remember that very dry bark is good at repelling water, so watering dry bark (assuming the pot has drainage holes) is often like water just running straight off a duck's back.

So if the dry bark isn't able to get water into it, then the orchid will take a bad turn due to not being able to get enough water.

On the other hand --- don't over-do it with watering --- since regular orchid roots being overly wet for too long --- can run of oxygen.

[Roberta]

The old pseudobulbs will not necessary plump up. In the natural scheme of things, they tend to lose roots, and provide reserves while the new growth is starting (with new roots) I do see new growths, so that's great. In fact, with new growth (which also gives new roots), this would be a good time to repot into a medium that fits your watering style. I suggest small bark. As ES noted, these do like to be on the damp side. So fresh small bark will give good air spaces and also hold moisture. When you water, water thoroughly. You can put them under the tap, and let the water flow through the pot. This flushes out accumulated salts and other crud and also pulls air into the root zone. Then lift the pot and feel the weight when it is freshly watered. In a couple of days, lift it again... if it feels lighter, water again the same way. If the water flows through the pot and the medium is fresh, the roots will get the humid air that they crave.

These very likely don't need distilled water, unless your water quality is really terrible. However, if you have a water softener, disregard the "under the faucet" advice... softened water contains salt, which is really bad for all plants including orchids... if that's what you have, take it outside and use water that hasn't gone through the system. Orchids will tolerate quite a bit of calcium in the water, but sodium (like in softened water) can be deadly to them.