What media dries the most evenly?

[Pinkeed]

I have been using bark with just about all my orchids for the longest time. Recently, I started experimenting with using seramis and leca. It seems to be working out ok with the smaller orchids, but not so much with the larger ones (mainly because I think I got seramis that was too tiny).

Some of the orchids I purchased recently are in sphagnum moss which I think might dry more evenly.

The problem is that I tend to over water my orchids. In the larger glazed clay pots the media does not dry evenly. The top is dry much faster than the bottom and it's a real problem. It can be 3 weeks or longer before the bottom is dry and this causes problems with the roots.

Does anyone know of a media that dries more evenly? Is sphagnum moss known for drying more evenly?

Should I switch to plastic pots? I do have some of the tinier ones in plastic, but it's hard to judge if this would help the large ones as well.

How do other people get their media to dry out evenly?

[Orchid Whisperer]

Ask 5 members this question and you'll get 10 answers.

It is really a combination of container and medium. Bark, in a terracotta pot, works very well. The pot wicks moisture away so the bark does not stay too wet. Change the pot to plastic or glazed ceramic, suddenly drying becomes less even. Change the medium to moss in a plastic pot, drying is more uneven still.

[jkofferdahl]

I only use sphagnum with plants potted in baskets. The open weave of the baskets allow air to freely move through and the moss dried in a couple of days. When using pots I'm old-school (being old), and still use bark. With larger Phals I use the biggest chunk bark available. Like OW, I also prefer terra cotta. I usually drill several extra holes in the pots before using them.

Plastic pots are another animal, and I think can be trickier to use. They don't breathe as does terra cotta, and so retain moisture. When I use them I like to notch a few extra holes close to the bottom of the pot for both extra drainage and extra air flow. But I think the key to using plastic pots is to use shallow ones; azalea pots are good. Shallower pots allow a better air flow and with better air flow the potting medium dries more evenly.

Or, you could try mounting them...

[Roberta]

I agree that shallow pots are better, especially with plants that don't have long roots, or roots that like to ramble. I have had good luck with not only Cymbidiums but also others such as Ansellia africana that also have long roots, using the Japanese pots that are tall and skinny. These, however, are not easy to find and certainly cost more than conventional pots. They do come in a variety of sizes.

Another trick, if you need a larger pot to accommodate roots but don't want a lot of space in the middle to stay wet, is to invert a small pot or basket in the center, work the roots around it as you pot. This creates an air pocket in the middle.

With Cattleyas especially, there's the "pot within a pot" technique - Santa Barbara Orchid Estate uses it a lot. A small plant starts in a small pot. When the roots grow beyond it, the plant is simply dropped into a slightly larger pot, with no media. The space between the pots tends to stay humid, but there's nothing to hold water, and roots of these plants that like to dry out get the moist air that they love. I have bought plants that had 4 or 5 pots (media only in the oldest one) with lots of happy roots.

[Ray]

After over 40 years of growing, in my opinion "even drying" is not nearly as important as folks think, as long as the air flow through the medium stays adequate.

When we water, the liquid does three things: most pours right through (I always "gained weight" watering the greenhouse), some is immediately absorbed but the plant and medium, and some is held in between the medium particles by surface tension.

It is that last category that is the problem, as that blocking of the air flow pathways leads to suffocation of the roots (attributed by many as "over watering," while in reality should be "use of too dense a medium").

The coarser the medium, the better to prevent that (until it decomposes), but I find coarse LECA and even lava rock to be best, as they wick the water pretty uniformly, preventing the interstitial water blockage.

[jkofferdahl]

Absolutely, Ray. Air flow is, judging from my own experience (A couple years short of yours, and probably a LOT less plants) absolutely vital. I prefer open, basket-type pots for this reason.

I think that a good way to look at your medium is to consider it as an insulation for the roots. Its job is to help them retain moisture, not to provide it like roots in soil. Rather than making your focus be the medium, then, make the focus the roots.

[Pinkeed]

Lots of useful information here! I am learning a lot. This is going to take me a while to take all this in.

My main problem is I get root rot near the bottom of the pot (anywhere from just the very bottom to 1/3 of the way up from that). I also worry that the top and middle don't get as much water while I'm waiting for the bottom to dry. But if I just water the root at the top it causes yellowing (so I have no way to keep it moist).

I think maybe like Ray and jkofferdahll said I need more airflow.

I might try out larger seramis. For now I have changed the larger plants I had in seramis and leca, to just leca and hopefully that will increase airflow some (since the leca pieces are bigger).

Roberta I will have to check out the pot within a pot technique. It kind of reminds me of neofinetia falcata pots. So this is essentially a small pot with no media in a larger pot? If I am understanding correctly? I'm guessing this would probably work well with epiphytes, but not so much with terrestrials?

Ray I have not tried lava rock. I'll have to look into that. I'm trying to move to media that doesn't break down as easily? How long does lava rock hold up? Where do you get this from?

[Roberta]

Originally Posted by Pinkeed

Roberta I will have to check out the pot within a pot technique. It kind of reminds me of neofinetia falcata pots. So this is essentially a small pot with no media in a larger pot? If I am understanding correctly? I'm guessing this would probably work well with epiphytes, but not so much with terrestrials?

This is definitely a technique that applies to epiphytes. Root rot is not so much a problem with terrestrials, as long as the mix is well drained, since a moist environment is natural for them. Epiphytes evolved to live with roots exposed to the breeze. (How well drained is the side of a tree? Very!) So these are the plants that need as much air as possible in the root zone consistent with their moisture needs. You're quite correct, Neofinetia falcata, at least when potted in the traditional manner, typically have a small pot, or other method of keeping an air space in the middle. These are Vandaceous (in fact, now classified as "Vanda") and very definitely need air in the root zone. The other approach I mentioned, though, is just the opposite - the plant starts out in a pot, but as it extends the additional pot(s) into which it gets dropped without media just provide an air space (1/2-1 inch, 1-2 cm) , which stays a bit humid, into which those roots tend to go. So that is more like mounting, except that the roots are "controlled" and do experience a bit more moisture. (Sort of a matryoshka doll-like environment)

Paul Gripp of Santa Barbara Orchid Estate claims that he stumbled upon this "drop into larger pot" quite by accident. He took some Cattleyas that were outgrowing their pots and dropped each, pot and all, into larger pots, intending to get back to actually repot them when he had a little more time. He forgot, and a year later found that the roots had grown vigorously into the space between the pots.

[Pinkeed]

Originally Posted by Roberta

This is definitely a technique that applies to epiphytes. Root rot is not so much a problem with terrestrials, as long as the mix is well drained, since a moist environment is natural for them. Epiphytes evolved to live with roots exposed to the breeze. (How well drained is the side of a tree? Very!) So these are the plants that need as much air as possible in the root zone consistent with their moisture needs. You're quite correct, Neofinetia falcata, at least when potted in the traditional manner, typically have a small pot, or other method of keeping an air space in the middle. These are Vandaceous (in fact, now classified as "Vanda") and very definitely need air in the root zone. The other approach I mentioned, though, is just the opposite - the plant starts out in a pot, but as it extends the additional pot(s) into which it gets dropped without media just provide an air space (1/2-1 inch, 1-2 cm) , which stays a bit humid, into which those roots tend to go. So that is more like mounting, except that the roots are "controlled" and do experience a bit more moisture. (Sort of a matryoshka doll-like environment)

I'm guessing they would need to be watered more often then? Not that I mind, if it solves the problem in the long run that means less work for me. I'm assuming these pots either have a lot of holes or are more like baskets? Or do roots just grow over the top?

[Leafmite]

Good luck! I hope you find the right set up for your orchids.