Potting materials question

[Sharyn]

I ordered some coir. What I received is ground up, looks like Schultz Peat moss. Is that the right coarseness to use in phals? I thought I'd try some of this when I repot.

What kind of perlite are you folks using? Is the stuff sold at the big box stores (like Miracle Grow Perlite) too small and lightweight? I'm asking because the perlite sold online specifically for orchids is larger and has a more coarse appearance.

And then, there's sponge rock - is that used the same as perlite? If so, what's the difference?

Last, but not least, what are the advantages & disadvantages of cocconut chips? I currently have at least one catt. in these chips & the stuff is as hard as a rock.

I know there's no one recipe for potting all orchids, but as I experiment, I'd like to get a better understanding of materials available and when to use them.

[mayres]

Hi Sharyn -
Coir can vary tremendously depending upon the source. It is actually the discard material after the long fibers of the coconut have been used for other things - like ropes, padding, etc. The material I have purchased comes in a large brick about 16X16X4 - from Sri Lanka. When you chip it off the brick and add water it is amazing how it fluffs up. People in our orchid society typically use the larger perlite too - maybe 1/8 to 1/4 inch - it is available (along with the coir) at a hydroponic store in town. I have managed to find some of acceptable size in a Fred Meyer (Kroger) store in town - in their plant department. Also have purchased a small bag of charcoal there - which is larger pieces than I like - so I have to smash it with a hammer to break it down a bit. So far so good. :-) Yep - sponge rock = perlite (synonyms best I can determine). I only have one paph in coconut chips thus far - as a relative newbie to this my guess so far is that it might last longer than bark (after a year and a half the media still looks good) and has better moisture retention than bark. You are certainly correct about there being lots of options - it is interesting to find what works for who and try to determine why.........

[arleneg]

Hi Sharyn,

Coir is sold 'ground up', either in loose or brick form. So far, my experience has been good. My Miltonia and Paph are potted in it. Both are growing very nicely since the coir holds a good amount of moisture.

When using coir, make sure you mix it with perlite (a.k.a. sponge rock) for aeration. I use medium perlite because the fine/small are too small (for my taste, that is). Some people mix it with perlite and charcoal (which I don't have, yet). Since it's difficult to find medium and large perlite at local nurseries or big box stores here, I order them online.

Not too long ago, I started using coconut husk chips. So far, my orchids potted in it are doing fine. The advantages I see is that it helps with raising the relative humidity because it holds more moisture than bark. Living in a low humidity area, especially during winter and summer, the extra moisture helps. I read somewhere that coconut chips helps deter certain pests and lasts 3-5 years. That means less frequency in repotting, unless needed. (ok, call me lazy ) I either use it alone or with medium to large perlite, depending on type of orchid.

HTH.

[Sharyn]

Mike & Arlene: Thanks for your input. I can see I have much to learn. If you don't mind, another question: I've heard that you should soak coir, since mine seems so fine, is that possible? Also, I believe I've read that the cocconut husks need to be rinsed quite a few times before using to rinse off salts? Just trying to get my info correct before I try any of these things. Thanks again for your replies.

[mayres]

I put mine in a vegetable colander and rinsed in the sink for awhile. Yes a little of it went down the sink, but the bulk of the material stayed inside. Seemed to work? In theory some of the suppliers are better than others in supplying de-salinated coir, but unless you have a salt meter or know from someone who does - best bet is to rinse very well.

[kmarch]

I think there might be 2 different things we're talking about in this thread. I have used both coir chips and something called coir peat. Both come in dried compressed bricks or expanded in bags. Coir chips are just what the name inplies, chips of choir material. I use it in a similar manner to the way I use bark, except that the coir chips soak up and retain a lot more water so I use it for plants that like the moisture (Paphs, Phrags, Phals). Coir peat, if I understand correctly, is the same material but ground up to about the same consistency as peat. It may be mixed with a little peat as well. I use this just like I use peat.

Sharyn, it sounds like your original post in this thread is describing this fine coir peat medium. Is that correct? If so I would not use it alone as a potting mix. I would add it to other things (bark, coir chips, perelite, charcoal, etc., etc.) to incerase the moisture retentiveness of the mix the same way you would use regular peat.

I hope this info is helpful and not confusing.

Happy Growing!

-Kevin

[Sharyn]

Yes Kevin, it's very finely ground coir, like peat moss. It's not what I was expecting when I ordered it, so not quite sure if I'm going to use this or not. If I do, I will definitely have to add bark, perlite or something else to it. Since everyone says it holds a lot of moisture, I'd have to be careful with this, especially over the winter months. I guess if I find that's it's making my media too moist, I can always use it in my mixtures for my container gardens. Thanks for your input.