Lava Rock & Lecca

[Ray]

“Too much water” was not the root cause of the issues.

When roots grow, they “tailor” themselves on a cellular level so that they’ll function optimally in that environment. Once they have grown they cannot change, so there is no “adaptation” to the new conditions. In effect, repotting makes them sub-optimal for the new conditions, so they will being to fail. How rapidly they do so has many factors, but one of the more important ones is how different the old and new conditions are.

The best time to repot is when new roots are emerging. Those roots will grow to be optimal for the new conditions while the old ones die and rot.

Phalaenopsis, for the most part are “hot growers”. 57F is entirely too cold for them in traditional culture, let alone with the evaporative cooling in S/H.

[Optimist]

To me, it sounds like they are suffering a set back, and all this "changing around" is not going to help the situation. I also think that leaf growth (smaller or larger) is caused by light levels and photosynthesis rather than medium types. (There is a lot to it because sun angle will also cause the enzyme cascade that causes growth). Leaves in the phal are storage organs for the sugar they make using the chemical components of the situation they are in, but it is mostly effected by light levels and PAR. (The width of the separate light waves from blue to red, you could say). Semi hydro should not be total hydro, so there is air but also moistness as well. It should simulate being in a constantly misty place, and not being soaked in water. Also when you change to a drastically new planting style, you will have root loss. Are you sure it was "rot?" I have been more and more in favor of using seedling heat mats under the orchids in the winter. I am in a fairly warm environment at other seasons.

[estación seca]

I belong to a lot of plant societies. When people ask me which orchid to start with in their home, I tell them to avoid Phals. Most homes are too cool for Phals to be grown easily. Some can certainly can be grown and flowered in most homes, but it takes a good and observant grower to do that. Witness the frequent, nearly identical Phal problems reported here on Orchid Board.

[OrchidLoverCA]

Yes, I agree with you. This is definitely a 'set back' phase due to the change from a bark setup to SH with Leca.

As for the light level, actually my orchids get more light in winter than in summer. They are on a very large two-sided windowsill located on the corner of the house where the two sides face one SE and the other SW. The sun is lower in the sky in winter, so its rays go straight through the windows, and shine on my orchids longer, whilst in summer the sun is higher in the sky and the sun's rays cannot penetrate at the same angle and for the same length of time (of course as the seasons come and go, I adjust the 'shading' accordingly to prevent sun burn).

Point is, I have been growing these Phals for several years, under the very same conditions they are now, except for the media of course. In bark they used to grow all year round, flowering from very early spring to late summer. Then they started growing huge leaves all fall and early winter, when they started producing spikes, etc. The roots were huge and active all year round. Here we don't have the kind of cold other growers experience in winter, when all their orchids become dormant or risk dying.

So, the only thing that's affecting my Phals is the actual change from bark to Leca. Being very large plants, I think they took several months to actually start feeling the change, because of their extensive reserves in their many leaves and their large root systems.

The main factor that set them back is, in my view, the change from a wet-dry cycle (more on the dry side) and a very airy chunky bark media to a very wet, moist enclosed media.

The velamen of the roots couldn't take it and the roots got all squishy and dark-green-brownish. Not real 'rot' as in 'sickness'. I treated them with fungicide to prevent that. But the root's structure suffered extensive damage. Like I said, it's the same effect you would have if you try to grow your Vanda in potting medium. Actually now I think of it, Phals ARE Vandas of sorts, LOL!

Anyway, describing my SH setup. Each individual plant is in a clear plastic container filled with Leca, with holes at the bottom (like a normal pot). Some are deli containers with drilled holes at the bottom (not the side), others are 7' clear pots because of the large size of the plants. Each individual container is then put inside a same size container without holes that will hold as much water as I want at the bottom as a reservoir. Meaning, I can vary the level of the reservoir and adjust it depending on the circumstances.

Every time I water the plants (once per week), I lift the inner pot out of the outer pot and throw away the 'old' water. The inner pot has holes at the bottom, so I can flush clean water right through. Or sometimes, I throw away the 'dirty' water, then I put the inner pot back in the outer pot and fill to the rim with clean water and let it sit 5 min to dissolve the extra salts before flushing all away.

Anyway, after the flush phase, I put the inner pots all back into the outer pots and refill the reservoirs with my fertilized water to level. I started with a level of 1/4 of the pot's hight but I have reduced it now to just 1'. At the end of the week sometimes there isn't any water left, but the Leca is still moist all the way to the top. The top layer doesn't become totally dry because I added an extra half inch top layer of river pebbles to prevent that. Still there is a difference between the moisture 'degree' between the top and the bottom, of course. But not that pronounced.

The water I use is rain water with a pinch of MSU. In winter the total TDS ends up between 60 and 80, and I adjust the PH to 6.5. My orchids are active all year round (so no dormancy). If I don't have rain water, I make RO water and add MSU and PH adjuster to the same values I mentioned. In summer I add more fertilizer according to orchid needs and ambient temp. Up to 160-200 TDS for Vandas and such (I grow Vandas in glass vases bare root, by the way).

Once per month I give all of my orchids a 20-30 min bath in kelp solution.

Like I said, now all my Phals are on heat mats through the winter because of the SH new setup, though they never were on heat mats before, when they were in bark and never minded my winter temp.

I thought, if I am to get help from you nice folks, I should describe my growing conditions as best I can. Sorry for the length of the comment.... and thank you for your kind replies.

---------- Post added at 10:13 AM ---------- Previous post was at 10:01 AM ----------

"well i know you asked ray, but figured since we have some similar issues with phals in s/h that i would chime in. we simply drain the reservoir really well with our phals. especially this winter. so, they are in leca and s/h but pretty much just grown with a dry reservoir. our 3 phals treated this way made it fine this winter..."

Tmoney, That's very interesting and I think I'm gonna try that, too....

[Leafmite]

Part of the problem with changing mediums is that roots can get cracked, nicked or broken during the removal of the old medium. These wounds make them vulnerable to attacks from organisms and fungus that cause root rot. Letting the roots heal (by keeping them dry or giving them plenty of air-flow for a few days) will help with the transition in most cases. I have moved many orchids into lava rock from NZ moss and bark without any issues...sometimes it just needs to be done more carefully, such as with Angraecums, Phal-type Dendrobiums and bifoliate Cattleyas. The more air in the beginning, the easier it is for the roots to adjust.

[OrchidLoverCA]

Originally Posted by Leafmite

Part of the problem with changing mediums is that roots can get cracked, nicked or broken during the removal of the old medium. These wounds make them vulnerable to attacks from organisms and fungus that cause root rot. Letting the roots heal (by keeping them dry or giving them plenty of air-flow for a few days) will help with the transition in most cases. I have moved many orchids into lava rock from NZ moss and bark without any issues...sometimes it just needs to be done more carefully, such as with Angraecums, Phal-type Dendrobiums and bifoliate Cattleyas. The more air in the beginning, the easier it is for the roots to adjust.

Good observation!
Could you please elaborate on how I can increase the air around the roots? Chunkier Leca?

[estación seca]

Put a thermometer into the Phal pots. It might be cooler than you think.

[tmoney]

your setup and conditions seem fine, and i hope you try and continue the setup before changing back again (if not for the plants sake!). i think all these guys are correct and driving at 2 points.

1. maybe wrong time to repot
2. its normal for plants to lose old, unadapted roots when going to s/h.
3. maybe too cold with additional evaporative cooling.

its ok, if you can baby them along till they get a new set of adapted roots, the plants will be fine. ihope you try drying them out more and see if that helps them as well. we also now keep them in full exposure hoping that any sun with help heat up the pots.

our experience was that with Paphiopedilums we had absolutely no problems with s/h and in fact grow all of our paphs that way now. phals were a much bigger challenge to get right in s/h, and only now by draining have we kept some alive. the roots did suffer on ours as well, so our experience is the same as yours. however, ours were small seedlings, so hopefully yours recover faster being older plants. best of luck!

[MateoinLosAngeles]

Originally Posted by tmoney

however, ours were small seedlings, so hopefully yours recover faster being older plants. best of luck!

For small seedlings placing them in an ikea desktop greenhouse under a heat mat and perhaps a fan running from time to time should help.

Phals shouldn't experience temperatures below 15ºC. Evaporative cooling can easily lower the temperature in the pot by 2-5ºC, if you're relying on your house's heat to keep the plants above 15ºC (assuming you have your heat set up to automatically maintain that temperature, which most people don't) you might actually be increasing the evaporative cooling rate due to the dry air cause by your heating system. So ambient humidity is the other factor to consider. A heat mat and a plastic barrier on top of the pot can help. I live in Los Angeles with generally warm temperatures and mild weather and I need to watch my Phals like a hawk.

Placing the orchids in full sun to heat up the pot might actually speed up evaporation therefore cooling the roots while overheating the leaves. Sort of a bad combination.

[tmoney]

hey mateo,

yeah, probly. but the sun/heat has been working and they are now all growing again now that spring has sprung. also, it is sort of our thing to grow orchids without any controls. partially it's laziness and cheapness, and partially its energy conservation.

our heat issue over the last winter, while traumatic to us cause it was colder than usual, really didn't set our phals back much. so yeah, if your are going for perfect, award winning bloom displays certainly one would want to keep the temps higher. but the business of you can't grow phals in chilly weather i just plain don't buy into. our experience has shown us otherwise.

certainly some species phals like the micholtziis struggled more than the hybrid phals with the colder temps, but most did spendidly and are spiking again. so meh, i don't let the temp thing stress me too much!! we aren't winning any awards tho, that's for sure! hahahahah