The Orchid Garden

Crown rot

Question:

I think you’re right about the supermarket culture Oliver. The Phal that I nearly lost to rot was bought in a supermarket and was upright. Now it is reforming on its side and doesn’t hold water very long. Also I have found that Phals do grow from shade to considerable sun. <Phil

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p pI think you’re right about the supermarket culture Oliver. The Phal pthat I nearly lost to rot was bought in a supermarket and was upright. pNow it is reforming on its side and doesn’t hold water very long. Also pI have found that Phals do grow from shade to considerable sun. <Phil Hi Phil, You and Oliver are correct about the lighting. While shade is safe and will do for most Phals, we’ve got some that grow right in with the Catt seedlings. There does seem to be a tolerance point and it may have to do with blooming, though for the life of me I don’t know why. Over time we’ve noticed that SOME of our Phals will tolerate much higher levels of light while in bloom, then start to suffer after the blooms fade. It’s not unusual for us to hang blooming Phals from the Catts hanging in the rafters. -Rod- Rod & Susan Venger, Venger’s Orchids Homepage address http://www.usa.net/venger/ Listings Available – Email us for your copies Order Line 1-800-483-6437 —

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p pHi Rod–I also find that Phals tolerate some pretty low temps. at pleast for a few days. <Phil Hi Phil, Yeah. But don’t forget that toleration isn’t quite the same as enjoying. Best to avoid it unless you’ve got a goal in mind. -Rod- Rod & Susan Venger, Venger’s Orchids Homepage address http://www.usa.net/venger/ Listings Available – Email us for your copies Order Line 1-800-483-6437 —

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Hi Rod–I also find that Phals tolerate some pretty low temps. at least for a few days. <Phil

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Hi Rod–My goal is to keep from carrying a big bunch of orchids into the house to avoid a couple of chilly South Florida nights. <G <Phil

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p pHi Rod–My goal is to keep from carrying a big bunch of orchids into pthe house to avoid a couple of chilly South Florida nights. <G <Phil Hi Phil, Sensible attitude! Remember though that carrying a big bunch of orchids into the house to avoid a couple of chilly South Florida nights is better than dumping that same load into the garbage. The weather these days is a little strange and even those that have a 99% chance of staying above 40 deg should shelter their plants against the wind..just in case. -Rod- Rod & Susan Venger, Venger’s Orchids Homepage address http://www.usa.net/venger/ Listings Available – Email us for your copies Order Line 1-800-483-6437 —

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Thanks for the reply Oliver–Do the "wild" ones have the same bacteria to contend with? Is hybridization a cause of leaning over? <Phil

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  Thanks for the reply Oliver–Do the "wild" ones have the same bacteria to   contend with? I am sure that they have a whole lot more; but perhaps not the same ones as they meet in a mixed collection. Is hybridization a cause of leaning over? <Phil Hybrid phals are vigorous compared to species – after all, they have been selected to be hardy and vigorous in perfect conditions, whilst species are tough, wary old birds, optimised to survive in variable conditions. The supermarket phal habit – upright, cupped – is probably the product of a mixture of their rate of growth, their having been grown in serried ranks under even light, of their often polyploid state. One could only know if you were to take a complex hybrid and stick it into a Phillipino jungle for a decade. Certainly, people who grow Phalaenopsis as garden plants in the tropics tend to have plants which try to hang horizontally, which shed water and which, for the most part, seem to be happy in full tropical sun. Having seem P. amabilis doing just this across its Pacific range, I am inclined to wonder about the "deep shade and continuous moisture" school which typifies cultural advice in books.   Oliver Sparrow

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Hi Ed–I noticed something else today in conjunction with a large Doritanopsis. When I sprayed it with liquid fertilizer the leaf junctions leaked and it drained pretty quickly. This plant looks for all the world like a large Phal but there is a subtle difference. BTW last year we had a monsoon season here and that was when I had my problem. <Phil

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Hi again Rob–Thanks for the reply! I got my problem during the constant rain of last summer. I noticed today that a Doritanopsis leaks at the leaf joints and doesn’t hold water. At least mine does. That probably accounts for the lack of problem with it last year. <Phil

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Virtually all wild Phalaenopsis grow with their leaves held vertically, and almost never for the "cup" shape which typifies hybrid plants. Additionally, the environment to which they are exposed is a complex and a changing one: mist at dawn, bright until mid-day, a torrential storm one day in three in the late afternoon, a dry evening and a cool night. Virtually none that I have seen have been in a wet-all-the-time environment: indeed, this is a highly specialised niche into which few if any Phalaenopsis species have penetrated: P. celebesense? P. micholitzii? Doritis grows around rocks in places where it gets very hot between rain storms:  essentially, it is an underbrush cactus, with the "little spears" of its infl. poking up through the scrub. Water certainly has little chance to pool. This said, crown rot is – as an earlier contributor noted – a generic term for a bacterial or fungal infection, typically caused by over-cool conditions, stagnant air, insect damage or any combination of factors which serve to weaken the plant.   Oliver Sparrow

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Could someone explain to me how it is that Paphs Phals and Doritis grow and do quite well in the rain forests but cant tolerate water in the crown at night in captivity? <Phil

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Could someone explain to me how it is that Paphs Phals and Doritis grow and do quite well in the rain forests but cant tolerate water in the crown at night in captivity? <Phil

        Sure, a combination of air movement and culture.  Your house is obviously not a rain forest, and orchids didn’t evolve to live there (although recent hybridizing is helping).  Phals growing in the wild are in trees and in serious air movement at all times.  I bet that house grown plants are grown better too, and the crowns are tighter (leaves are thicker and closer together) due to adequate or overadequate fertilizer.  Less attrition of leaves too.  That is just a guess though.  Also nature has a more complex ecosystem.  That fungus that causes crown rot in your greenhouse has no predators, but in the wild there may be things living in the crown of the plant (single celled organisms, lord knows what else), that keep things in balance.  Nature is funny that way.  Actually the pathogen that causes crown rot may not exist at all in the rain forest, it could be a "foreign" invader local to more temperate climes.   Rob  Rob’s rules to live by:                            |  Send me seeds!    (1) There is always room for one more orchid.    |    (2) There is always room for two more orchids.   |    (3) There is no rule 3.                          |  Hey kid, wanna buy a     (3a) When one has insufficient credit to buy    |     Paph?          more orchids, obtain more credit.          |

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p pCould someone explain to me how it is that Paphs Phals and Doritis pgrow and do quite well in the rain forests but cant tolerate water in pthe crown at night in captivity? <Phil Hi Phil, One major reason is that the 3 genera you’ve mentioned are not forced to grow upright in pots out in the wild. Two of those 3 frequently grow sideways, so water never has a chance to collect. One thing to remember is that crown rot isn’t caused by water. Water will soften the tissues however, making it easier for pathogens to enter. You’ve seen references here and there about our "Phrags growing in nothing but water" experiment? (They’re doing just fine, BTW). One of those jars has a very tiny seedling that has been completely immersed, no air touching any part of it, for months now. It not only hasn’t rotted, but it’s growing. -Rod- Rod & Susan Venger, Venger’s Orchids Homepage address http://www.usa.net/venger/ Listings Available – Email us for your copies Order Line 1-800-483-6437 —

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In addition to the rain seasons and growing habits, in the wild the constant breeze dries things up. Living is like licking honey off a thorn

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Hi Rob–All my orchids are in the garden all year. Last year I almost lost a large Phal and a Doritis to crown rot during the heavy rains of summer. The Phal rotted down to the bottom leaf and the doritis went all the way but I saved it’s pups. Rod Venger indicated that Phals try not to grow vertically and I can see this tendency but the Doritis is an upright grower and this carries also into Doritanopsis. I was curious about the comparison of wild and captive phenomenon. <Phil

        Actually I think Doritis grows in almost pure sand, rather than in trees (don’t know why I think that…), and it certainly grows upright, as do Paphs.  It is certainly a mystery as to why some get crown rot and others don’t.  In addition to my previous bits about air movement and ecosystem babble (which I think probably accounds for most of it), note also during the rainy season these plants are getting inches of rain a day.  Any water remaining in the crown from the previous day is likely to be washed out and replaced with fresh water the following day.  It doesn’t get a chance to get stagnant and have a lot of stuff grow in it.  How’s that for an answer from somebody who hasn’t been out of the midwestern US in 20 years…. *grin* Rob  Rob’s rules to live by:                            |  Send me seeds!    (1) There is always room for one more orchid.    |    (2) There is always room for two more orchids.   |    (3) There is no rule 3.                          |  Hey kid, wanna buy a     (3a) When one has insufficient credit to buy    |     Paph?          more orchids, obtain more credit.          |

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Hi Rod–I think you’re essentially saying that the same risk exists in the rain forest as anywhere if they grow vertically like Doritis. <Phil

Response:

Hi Rob–All my orchids are in the garden all year. Last year I almost lost a large Phal and a Doritis to crown rot during the heavy rains of summer. The Phal rotted down to the bottom leaf and the doritis went all the way but I saved it’s pups. Rod Venger indicated that Phals try not to grow vertically and I can see this tendency but the Doritis is an upright grower and this carries also into Doritanopsis. I was curious about the comparison of wild and captive phenomenon. <Phil

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Could someone explain to me how it is that Paphs Phals and Doritis grow and do quite well in the rain forests but cant tolerate water in the crown at night in captivity? <Phil

That has always been a mystery to me. Some say that Phals in nature grow slanted. Some growers slant their pots. Maybe they get a better breeze at night. For sure, they don’t get as much fertilizer in the crown. Maybe their temperature drop is different at night. As for Paphs, from pictures I saw, they seem to be growing straight up. But many times it’s the lower leaves that start to rot and not so much the center. In monsoon sites they get a continous washing during monsoon. After monsoon they probably go dormant and don’t want any water. The problem in the northern Hemisphere is to find out when it’s time to monsoon them and when it’s time to leave them alone. Ed Cormier

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