Can I grow my orchids without any medium?

[ViolentRainbow]

I'm pretty new to orchid care, I bought a mix of orchids most are dendrobiums and one is a cymbidium. I had them in hanging baskets outside in the shade planted in chunky pine bark and perlite with slow release orchid food. They didn't grow much at all but they stayed looking very healthy.

I live in Australia and it's late autumn now and getting very cold at night and also some tiny caterpillars that dangle on strings have been hanging around them so I decided to dig them out and bring them indoors. The roots look very healthy and have grown a lot. I washed them off and I have them laid out on a towel.

So basically my actual question is can I grow them indoors without any kind of potting medium? I have an old small fish tank and a plant grow light that I can fit them all in, I want to put them in there over winter in my bedroom. The tank holds humidity well and has some holes in the roof for ventilation. If I just mist the orchids daily and also give their roots a mist of water and liquid fertilizer occasionally will this be ok for a few months?

[tmoney]

howdy, welcome to the orchid board!!

your question is far too complicated for my little brain, but i would ask first if you know what kind of dendrobiums you have as there are different ones that need slightly different winter care (if my understanding is correct). i know nothing of cymbs since we don't grow any.

anecdotally, i would guess anything is better than nothing, but i think a lot would depend on what types you have. we were advised to leave our dendro outside for the winter (NOT saying you should do that as ours is probly a more mild winter than you have) and it did just fine, but it is totally possible that you have a different kind of dendro than us.

if you have names then posting them might help our more experienced members provide you with more targeted advice.

[Roberta]

Welcome!

The Cymbidium will not be happy bare-root. It grows pretty much as a terrestrial. How cold will it get? Most Cyms (if acclimated) can do fine down to about -1 or -2 deg C at night if the days are warmer (15-18 deg C). In fact, most Cyms need a fall cool-down (cool nights and warmer, bright days) to set spikes. It is really difficult to keep a Cym happy indoors at all. Unless you have serious frost, no need to bring it in. (Unless it is one of the hard-leaved tropical ones... do you have a name for it?) I hope that you have not set your Cym back too badly by unpotting it this time of year - the time to repot Cyms is in the spring, when new growth is starting. Fall is when they are getting ready to bloom, and should not be disturbed. (For most, bloom time is late fall into winter, and then in spring depending on parentage) So get it back into that pot!

tmoney's question about "which Dendrobiums" is spot-on. It is a huge genus, and different species (and their hybrids) have very different needs. This was not a good time to unpot Dendrobiums either... the time to repot orchids is when they are starting new roots. Typically, that is in the spring. Some types, that pretty much "rest" in winter (not doing much, want somewhat reduced water but not completely dry) probably won't be harmed. The ones that don't slow down in winter likely won't be happy, though. So knowing which ones you have will help us to give you advice.

[ArronOB]

Yep, we need to know two things.

Firstly where in Australia are you - big differences in winter temperature exist. Please put your location in your profile so we can give targeted advice.

Secondly, what type of dendrobiums do you have. Being that you are in Australia, they are likely to be either native dendrobiums which are usually descended from D. kingianum or D. speciosum, or the non-native temperate-growing D. nobile.

Generally, unless you are in southern Tasmania I would have left the cymbidium outside in a sheltered position, and the dendrobiums we will see when we know what they are.

The way you propose to keep your orchids through winter sounds like a good way to grow mould, but maybe not so good for orchids.

Cheers
And welcome to the group.

[Optimist]

One thing I have learned is if you remove an orchid from it's medium, the roots often must adjust so you have "shock" of some kind. People who change out the medium are just putting new medium that has not broken down due to water "decaying" or turning the medium to "compost" which also leads to a lot of nitrogen. Orchids that grow on trees are on a living plant, and so there is no "composting" going on.

Taking an orchid and putting it in a different medium, for instance, going from bark chips to rocks, and misting, are totally changing the situation around the roots, and in some cases, if you go to semi or full hydroponic, the roots that grow out will be adapted to that situation alone. So constantly moving from one type of medium to another type can shock the plant causing set back. So if you are going to move the plants, you should move to and from "similar" medium situations.

Orchids like good airflow. Many actually live in areas where there are dry and rainy seasons. I've found several types of dendrobiums like constant moisture at the roots (Latouria, and cannaliculata crosses) but do not like it on their leaves. Although there is a mental image of "misty" jungle and so on, that is only usually at certain times of the day, often morning when hot and cool air mix. Keeping an orchid in that situation full time would be asking for crown rot.

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