S/H pot depth

[jkhom]

I bought a bunch of S/H pots from Ray's and they are deeper than clay pots of the same diameter. I was wondering if there is a reason for the extra depth. Does this have something to do with the wicking properties of the primagra? Would I be able to use plastic containers that are more shallow?

[Ray]

I use taller pots for paphs, catts, oncids, and cymbidiums, shallower ones for phals and bulbos, although in truth, it's not all that critical, unless you grow in a very dry environment.

You have to consider the balance between the wicking of moisture from the bottom and its evaporation from the top.

If the distance from reservoir to top is small (squat pots), the medium will tend to stay more-or-less evenly moist throughout the pot. When that distance increases, the wicking cannot keep up as well, so the medium at the top dries out. (In a humid environment, that is not the case, and in a very dry one that "dry line" moves pretty deep in the pot. It is common to see it move with seasonal- or weather-related changes in humidity.)

I used to think that taller was a real advantage, as the plants could decide just how wet they wanted their roots by controlling the depth of penetration, but I've decided now that its unimportant, as all plants will grow roots right into the reservoir! Now I base pot choice on the root system and growth habit of the plant.

[Becca]

Ray, so are you saying for those with lower humidity, like me, that it maybe better to have a shallower pot? I only have two 'chids outside of my orchidarium in the low humidity and I still have problems with them. The new root growth seems to eventually rot and I was wondering if this was happening because of the rapid evaporation due to the low humidity. I would think the new roots would adapt and be fine. Come to think of it I do have one other in s/h sitting in my window sill and it is in a smaller and shorter container and it seems to be fine.

[quiltergal]

Becca, I think that's exactly what Ray is saying. You could either move them to a squatter pot, or water more often. I think either would accomplish the same thing. I think that's how I lost my Slc. I only watered once a week not understanding that the roots were in the dry zone. The new roots that grew were growing up and away from the PrimeAgra (looking for moisture I would guess). The pot it was in was also too large which contributed to the problem. I can only presume that had I watered that one several times a week it might still be alive with roots growing down instead of up.

[Sun rm.N.E.]

Becca

I have another suggestion. When I observed my new catt root tips turning black as soon as they penetrated the medium it was not characteristic of black rot since it did not spread at all, right above it new healthy branches formed very soon and have remained healthy. Then I saw a post by Ray talking about mineral damage. Indeed the top of my media had very heavy mineral deposits. Flushing with clear water and replacing the offending pellets seemed to help. Still no real evidence of root rot anywhere else on this new root system after a month.

By the way, I think the new medium seems to take much more rinsing. I have used the same method with both new and old media in pots side by side this Summer and I did not notice as much accumulation of minerals on the top of the old media in the past 5 months.

[Becca]

Thanks for the info, I hope all of this will help jkhom some. As far as heavy mineral build up, I do have problems with this as well. I have flushed and flushed and flushed and it doesn't go away. I have tried resoaking the medium in a solution of calcium nitrate and magnesium sulfate (Epsom Salts) that Ray has on his webstie. His website states this is "Similar to the process of a water softener, the Ca and Mg ions substitute for the less desirable soluble minerals in the pellets." But I still have problems with the mineral build up weather it is with the orchids in s/h in high humidity or low humidity. Perhaps there is something else that is wrong with my culture that I am missing.

[jkhom]

Thanks everybody.
This is my first attempt at S/H.
I will try to vary the pot depth depending on the moisture requirements of each plant. My concern was that if the pot were to shallow, it would be too wet and promote root rot.

[sept2256]

it is a very interesting discussion. I had the same doubts. So, let me repeat if I have well understood.
In case os dry environment (like my house) It is better to use normal (shallow) pots. In case of right (hight) humidity, taller pots are preferable. But what happens if also in this second case I use shallow pots? I thnk nothing!! So why don't use only shallow pots in all cases?

Ray sad "Now I base pot choice on the root system and growth habit of the plant." Ray, what does it mean?
Thanks, Pierangelo

[Ray]

Becca,

If your household humidity is so low that the evaporation is rapid, your issues are likely caused by localized evaporative cooling. Phals are particularly sensitive to that, so for mine in s/h, I never let them go below 65°.

We need to discuss that mineral buildup issue, as that seems very odd to me. Please email me.