Begging your pardon, my dear lady, it isn't quite propper [sniff] to refer to orchid bark as wood chips as they were. There is an, ahh... decorum about such matters. Plenty of us make our own mixes, usually in order to utilize materials other than, er, wood chips. About the only woods commonly used in orchid culture are coniferous trees namely Fir, Pine and Redwood in order of popularity. It is not the heartwood that is used but the bark so if you have access to wood shavings from some kind of industry (furniture?) I don't think you can get too much assistance from the community here, you are kind of on your own with that. When making a mix you can't go too far wrong if you use the rule of three. That is, three parts of the main ingredient of your mix and one part of any supplemental material(s) OR 50/50 of any one ingredient commonly known to be 'organic' and one commonly known to be 'inorganic'.

H

If you are talking about bark, fir bark is most commonly used and is an excellent orchid medium. I like it best in a medium to somewhat course grade, just as it is with nothing added. Others prefer some charcoal with it and/or perlite and/or other things.

But since you mentioned wood chips, I'll admit to a bit of experimenting myself. I tried using wood chips with fir bark in wooden baskets. The objective was to find a suitable natural additive to mix with fir bark that would make repotting less expensive.

What I used were the most rot resistant types of wood I could find. And what I found most readily available were hickory, alder, and mesquite wood chips that are sold for barbequeing. One problem with these is that they are mostly cut like little slabs. Irregular shapes would be better - if it were a good idea to use wood chips at all. The flat chips tend to stack together, restricting air circulation.

After a few months in the baskets, I checked toward the centers of the media and found that the surfaces of the wood chips had a slimy feel and they had spots of greenish fungus on them. They were absorbing and retaining water more than I thought they would, and certainly more than the fir bark did. I should have foreseen that. Wood and bark have different water-handling properties as parts of living trees also.

Based on this one trial, I came to the conclusion that wood chips are NOT a good orchid medium.

I would think the best wood chip would be one (single) chip large enough to mount the entire plant upon. More of a hunk or plank, than a chip.
-MB

Howard, my sincerest appologies, (wink,wink)! How could I??...however, the wood chips I am referring to, came when we had arborists trimming our trees and chipping them. I have a huge truckload of chips -- bark, inner wood, whatever that is a mix of douglas fir, maple and oak. I am also going to have some cedar after they visit next time. the chips are quite irregular and vary in size a lot so I thought I might try mixing some with perlite and some sphag. Especially for the cyms. I think I will soak it first because there is a lot of tea coloured water coming from the chips when they get wet. Last spring, I divided a couple of cyms and tried various mixes: a regular orchid mix, sphag, clay pellets and donkey poo. The last from the poster here who used horse poo. They are all still alive and doing well but I really don't see much difference in the growth. So, perhaps the media used is just to keep them anchored in their pots. I'm a little fussier with my other orchids but it is fun to experiment.
Thanks for the replies all.

I thought raw bark/wood chips had to be treated first with a whole mix of chemicals. Someone (maybe Arthur) posted this a while ago.

Kevin

I use medium white or douglas fir bark. I wouldn't use wood chips (like heartwood or non bark). I make a mix of fir bark, redwood bark, perlite, and some canadian peat. My friend uses red cedar chips and has success.

What are the best wood chips for growing orchids? Well, none that i know of.

In the Pacific North West what is the potting material that most orchid growers use?

And as far as treating your own pine bark. That is only a goer for those people with huge collections and then only for the driven. One guy i know has 5000 orchids and used to boil and treat raw pine bark. No. i'm not going to give out the recipe because in my view you are better off going out and spending your hard earned on a commercial product.

We used to use Fir bark in the good old days but it is no longer available here. Not sure if that was treated or untreated Fir bark.

At latitude 34S, Sydney, Australia most orchid growers use mixes where the basic ingredient is treated pine bark. I use treated pine bark, Coconut chunks and Diatomite. Works fine here. Might be hopeless in the PNW.

Thanks for the replies. I think I will pot up one cym in wood chips and see what happens. I have one that burst its pot and there was no room in the pot for anything other than roots -- the original media seems to have disappeared.

You may find nitrogen drawdown to be an issue if you're using wood. Softwood bark is often partially composted to reduce problems with nitrogen drawdown (this also reduces the various phytotoxics compounds present in many conifer species). As I understand it, wood has a higher C:N ratio than the soft wood bark normally used in orchid mixes and therefore wood mixes will be more susceptible to nitrogen drawdown. This is the reason why wood and sawdust (especially uncomposted) are avoided in general potting mixes. Hungry orchids like Cymbidiums would no doubt fair very poorly in a wood mix.

I agree with Coymbosa, wood chips use up a lot of nitrogen. I would not use wood chips. The tend to rot fast too. Stick to fir bark. Most orchid fir bark like white fir and douglas fir have been stream treated to remove disease and rid the bark of resigns. Pine bark has a lot of resin and seems detrimental to the plant. That's why some pine bark used for plants are also steam treated. Cedar bark and redwood bark chips are a good additive to fir bark. Adds a bid of acid in the bark. Bark mixes usually require extra nitrogen when fertilizing. 30-10-10.
I don't like coconut chips because they seem to hold on to salts. Causes roots to burn. Chalky buildup. Chopped tree fern is sometimes added to bark mixes. Charcoal is good too. Helps keep the mix fresh.
In the old old days, cymbidiums were planted in a mixture of Oak compost.

If you use wood chips you're going to have to monitor your plants very carefully as the wood chips may break down very quickly and the roots of the plants may start to rot. The medium may look good above and be rotten below.

i say forget about wood chips or bark

i use pure diatomite now. it is inorganic and never rots
doesn't need to be treated and repotting is a piece of cake
i hate the process of getting the rotted bark out from between the roots! HATE IT!

see the light and turn to inorganic mediums
i could also agree with mounting though, that also solves the problem of rotting medium

Elvinwei, I think you are in California. Can we use diatomite in CA with our hard water?. I have a big bag of diatomite.

There is no magic potting mix. What you use depends on Climate and other factors. I'm not going to say use such and such because there are all sorts of factors to be taken into account.

The blurb on the outside of my 40 litre bag of Diatomite says mix 10/15% of Diatomite with your other potting ingredients. If you are in doubt just put some chips on top of the potting material and see what happens. It seems to be beneficial but i've got no idea why. Every orchid i own has some in the mix or chipped and sprinkled on mounts. Not that i have many mounts. Only for orchids that grow best that way. I'll say it again. Mounting means Maintenance.

Again. Select potting material(s) that is right for all the variables, the plant, the pot size, your growing conditions.

Treated pine bark is no good statements might be right for tropical climates and some watering habits. But look at the picture. All those orchids are potted in bark based mixes.

Here is a link that might be useful: Orchids in a shadehouse

a man sold be some large pine bark as in mulch -- but I chickened out. You can get redwood kiln dried - for me its $12 for a large bag - depending on what I am doing I mix it -- for cyms no. I have a lot of plants and it took about 4 bags of medium and fine for several hundred plants -- I use a lot of peanuts and perlite - large. I Pine bark I am told will not hold up.

Hi, I have my 1st two orchids delivered in clear pots with bark as a medium. I live on Rhodes Greece and there does not seem to be a supplier of bark but there are many Fir/Pine trees here, if I collect the bark from them would it be safe to use, I have to ask the question as these are my 1st orchids and I would like to keep them thriving any advice please.

Dotty & Russell, as others have said, fir bark is good for potting orchids.

The fir bark I use is a commercial mix. The bark has been heated to 375 degrees for 30 minutes to get rid of fungi, bacteria, insects and snails. If it's that straightforward, you could heat it in the oven. However, I have no idea if it receives any other treatment before going into the mix.

After all treatment, it's mixed w/ 1/3 charcoal and 1/3 perlite or sponge rock. You can also buy just the bark and make your own mix.

If you experiment, let us know how it turns out. Whitecat8

My oldest son got me and my mother orchids for mother's day 2 years ago when we lived in Florida. I now live in Ohio and mine is dying I think. Repotted it in tree bark and apparently I have been watering incorrectly, ie. Dumping water on top of it. It looks severely dehydrated with leathery looking leaves. I cut off all dead roots as suggested and even tried the tea soaks. The core is still green. I just don't know what to do for it anymore and I'm really attached to it. Any suggestions for rehabilitation or rescue?

What is tree Bark i.e. What sort of Tree? Radiata pine, Fir?

Where is it kept? How often are you watering? How exactly do you water?

That should get the 'discussion ball' rolling anyhow.

Bob