Shop Orchid Care OrchidTalk Orchid Forum Weather Station Links Nursery

Welcome to OrchidTalk Orchid Forums


The Friendliest Orchid Community on the Internet!


  •  » Learn to Repot your Orchids
  •  » Learn Orchid Care Tips and Secrets
  •  » Find the perfect Orchid for your Growing Environment
  •  » Chat with Orchid Growing Professionals

OrchidTalk - "Bringing People Together to Grow Orchids Better!"


Let us help you grow your Orchids better; Join our community today.


YES! I want to register an account for free right now!


Register or Login now to remove this advertisement.

Results 1 to 8 of 8
Like Tree7Likes
  • 2 Post By sand_tiger86
  • 2 Post By Halloamey
  • 1 Post By serama
  • 1 Post By tucker85
  • 1 Post By Dorsetman

How do orchid roots survive?

This is a discussion on How do orchid roots survive? within the General Orchid Culture forums, part of the Orchid Culture category; As we all know, (most) orchids grow on tress - bare root, clinging for life ...

Click here to increase the font size Click here to reduce the font size
  1. #1
    sand_tiger86's Avatar
    sand_tiger86 is offline Senior Member
    Real Name
    Kelly
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    Vandas and Catts
    Join Date
    Jul 2007
    Gender
    Male
    Location
    Texas
    Posts
    811

    Default How do orchid roots survive?

    As we all know, (most) orchids grow on tress - bare root, clinging for life and exposed to the elements. It's said that the roots will rot easily if potted too tightly or in the wrong medium, or the wrong kind of pot. But I've been thinking about it, and putting them in ANY kind of pot seems like a complete wrong-doing from the way that they grow in nature. For example, most people put Phals. in sphagnum moss because they come from moist areas and like to kept that way...but the moisture they get from nature is from rain and thick humidity on their exposed roots and they're allowed to dry off quickly. Orchid roots need to breathe and be exposed, so it would seem like putting them in a pot (whether free-draining or not) would significantly reduce their ability to fight off rot. Obviously, rot does happen (and often), but you'd think it would be a lot more common place simply based off the fact that they're in a stagnant pot of wet media for at least a day or two (minimum) before drying off. And furthermore, why is the potting media different for Vandas? All epiphytic orchids have their roots exposed in nature and don't like some soggy media wrapped around them...yet, as mentioned, in pots almost all do fine provided you don't water too often. Why do Vandas rot so quickly if you have them in any standard orchid media?

  2. #2
    gardenguysorchids's Avatar
    gardenguysorchids is offline Don't be afraid to color outside the lines
    Real Name
    Bill
    My Grow Area
    Under Lights
    Favorite Orchid(s)
    Paphs, Oncidium,and Catts
    Join Date
    Sep 2009
    Gender
    Male
    Location
    Mechanicsburg, Pennsylvania
    Posts
    3,526
    Member's Country Flag

    Default

    I like what you are saying very much. I also can't understand why one shouldn't summer paphs and phrags outdoors due to the chance of them rotting if water gets in their centers. How is that controlled in nature? I know it is solved with phals by the angle in which they grow sheds the water but paphs and phrags grow vertically from the ground and are usually growing in areas with lots of rain. How is the rot controlled in their natural state? You have been on a roll lately with presenting great threads that make us think. Good going, buddy! You definately are a winner!

  3. #3
    sand_tiger86's Avatar
    sand_tiger86 is offline Senior Member
    Real Name
    Kelly
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    Vandas and Catts
    Join Date
    Jul 2007
    Gender
    Male
    Location
    Texas
    Posts
    811

    Default

    Thanks, Bill!

    I don't understand the Paph./Phrag. thing either. They also live in places that are MUCH more wet than the average suburban area, as well, so in theory you'd think they'd have less of a chance of rotting in said environment. I don't buy it, myself, because it just doesn't make sense. I think the reason you shouldn't summer Paphs and Phrags outside is because of their low light and heat requirements.

  4. #4
    Halloamey's Avatar
    Halloamey is offline Senior Member
    Real Name
    Amey Bhide
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya alliance
    Join Date
    Jul 2009
    Gender
    Male
    Location
    Pune, India
    Posts
    5,363
    Member's Country Flag

    Default

    I am not sure about Phrags, but Paphs also grow at angle, some time on vertical rock faces so that takes care of water not reaching the crowns. Secondly it is very wrong to compare what happens in the wild to what happens under our growth conditions. Rot is not simply caused by water getting into the crowns, you also need the bacterial and fungal pathogen that can cause the rot. In nature orchid populations are interspaced sometimes hundreds of metres if not kilometers apart, so if one plant gets infected, it dies, may be the neighboring orchids in its community die, but the disease stops there since the pathogen cannot physically move between the populations on its own. And now imagine an artificial scenario where we grow our plants, there is a mixture and number of orchids you will never find together in nature. On top of that there is always some ailing plant in our collection that we keep trying to save, nature is rather unforgiving the infected plant will most probably die and later the pathogen will also die out, but in our growing system we keep the source of infection around, even if you quarantine you cannot be 100% sure. Thirdly there is a principal difference between wild plants and cultured plants on a genetic level. Out of the millions of seeds produced and a few hundred plants that germinate only the toughest and strongest of the seedlings survive they have better immune systems, whereas the plants we grow are germinated on sterile agar media, and raised with a constant dose of fertilizers, pesticides, fungicides and hormones, they are essentially weaker compared to their wild cousins. Also in nature all plants are in some form of symbiotic interactions with beneficial bacteria and fungii that colonise their leaves and roots and outcompete the pathogenic varieties, we lack such associations in our plants making them much more susceptible, so really cannot compare wild and home grown plants.
    Quote Originally Posted by gardenguysorchids View Post
    I like what you are saying very much. I also can't understand why one shouldn't summer paphs and phrags outdoors due to the chance of them rotting if water gets in their centers. How is that controlled in nature? I know it is solved with phals by the angle in which they grow sheds the water but paphs and phrags grow vertically from the ground and are usually growing in areas with lots of rain. How is the rot controlled in their natural state? You have been on a roll lately with presenting great threads that make us think. Good going, buddy! You definately are a winner!

  5. #5
    serama's Avatar
    serama is offline Senior Member
    Real Name
    Tony
    My Grow Area
    Greenhouse
    Join Date
    May 2012
    Gender
    Male
    Location
    Yorkshire, UK
    Posts
    123
    Member's Country Flag

    Default

    And here comes the science lesson of the day:

    As Amey says, many paphs actually grow in rock crevices on cliff faces, where their leaves hang down and their crowns are at an angle that allows for quick drainage. Also, in these places they get a lot more light than people think because there are no trees or other plants casting any shadows around them and they tend to get direct sun light either in the morning or the evening. They also receive a lot of air movement for the same reason, which helps them dry out as well. These are the species that are notorious for rotting in the blink of an eye (Paph. bellatulum, godefroyae, etc.).(cxcanh has some great pictures of this in one of his threads in this forum). If you look at the plants you'll see that they have fairly small but thick leaves, which act as a reservoir for moisture.

    Then there are the true ground dwelling species, which indeed do have upright fans of leaves and will therefore collect water in the crown when it rains. But again, you have to take into account that most of them live in very hot climates, where they'll dry out fairly quickly after it rains. Good air movement (which yet again is fairly hot) helps with this too. Then there is the duration of the rain. When it rains, it rains for hours on end, which cleans the plants and washes them. This means that the water inside the crown doesn't become stagnant, as it is constantly being renewed by fresh water. When we water our paphs we tend to do it every few days as they stay wet for a long a long time. In their native habitats they are drenched for hours every single day during the wet season, but then dry out quickly after the rain stops. This is difficult to replicate in our greenhouses. The stagnant water on he leaves and crown, lack of air movement and suboptimal temperatures quickly leads to crown rot when groing these species in our temperate climates.

    Phrags also tend to grow on steep surfaces (that is why many of the species grow upwards, with a long rhizome between the fans of leaves), the difference being that these are generally the gullies and embankments of rivers rather than mountainous rock surfaces. These are naturally very wet and therefore phrags can cope with being wet at a level that will kill most other orchids (as a matter of fact they love being wet). The surfaces they live on are always wet with a constant trickle that flows down to the rivers, this means that they don't like stagnant water, so it's best to water them often and flush their media rather than standing their pots in water when we grow them. Rockwool and sphagnum moss are more forgiving of this and phrags potted in these media can be stood in water, but bark mixes will decay very rapidly and rot if stood in water, which then kills the phrags.

    Finally vandas, these are true epiphytes that grow in exposed situations, mostly in full sun light in scrubs or trees where there is constant air movement and a lot less moisture available to them than to orchids that grow in more shaded and protected places. Whereas many epiphytic orchids have sparse root systems that are nontheless enough to anchor them in place and supply the water and nutrients that they need (often these roots grow into a thin humus or moss layer), vandas have very thick roots that they throw out at right angles from the stem, which travel for several meters in all directions and of which only a few are actually clinging to the branches and trunks of host trees. The majority are simply dangling around, completely exposed to the elements and even those that cling to a surface tend to attach themselves to bare branches and trunks (because of the sun, heat, air movement, etc., there is little to no moss where vandas tend to grow). This means that the roots are dry for most of the time, but they have a thick velamen and are good at absorbing moisture from the air as well as any rain that falls on them. The result of all of this is that vandas do not like to be grown in pots. It would be difficult to accommodate the huge root systems in small to medium pots (and most of the plants tend to be quite big themselves), so large pots would be necessary and these would keep the roots wet for long periods of time as they take longer to dry out, which then leads to the roots rotting as they are not designed to be in stagnant conditions.

  6. #6
    tucker85's Avatar
    tucker85 is offline Senior Member
    Real Name
    Jeff Tucker
    My Grow Area
    Porch/Patio.
    Favorite Orchid(s)
    Cattleyas, Phalaenopsis, Vanda
    Join Date
    Jan 2011
    Gender
    Male
    Location
    Plantation, Florida
    Posts
    2,446
    Member's Country Flag

    Default

    Very well said, Amey. That's an excellent explanation.

    Since I retired, a couple of years ago, I've been slowly moving my orchids into open wooden baskets and a couple on mounts. My vandas have their roots hanging free with no medium.

    It's very rewarding to grow orchids in a more natural way and most orchids respond well to it. But when we're working every day, most of us don't have the time to give the extra care that orchids need when they're grown that way. For example, I water my vandas every day now. So we resort to methods that will allow orchids to go a little longer between waterings and fertilizing. Luckily, over the years, growers have discovered culture methods that many orchids will tolerate even if it's not their natural state. That's why we're here on this forum, to learn some of these tricks.

  7. #7
    Brutal_Dreamer's Avatar
    Brutal_Dreamer is offline Dreaming with my eyes open...
    Real Name
    Bruce Brown
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleyas & Slippers
    Join Date
    Mar 2003
    Gender
    Male
    Location
    Arkansas
    Posts
    34,003
    Member's Country Flag

    Default

    Thanks Amey and Tony! Bravo!
    cheers,
    BD

  8. #8
    Dorsetman's Avatar
    Dorsetman is offline Senior Member
    Real Name
    Geoff Hands
    My Grow Area
    Greenhouse
    Favorite Orchid(s)
    Cattleya ?
    Join Date
    Oct 2010
    Location
    England, South coast.
    Posts
    3,246
    Member's Country Flag

    Default

    Quote Originally Posted by sand_tiger86 View Post
    . . Why do Vandas rot so quickly if you have them in any standard orchid media?
    They don't. I have some vandas potted in pure coarse Perlite. I have others potted in coarse pine bark chunks - the size of a shelled Brazil nut . I have others potted in a mix of medium bark with charcoal and sponge rock pieces ( as used for some of my paphs). I have others potted in Coconut husk chunks measuring up to an inch or even an inch and a half, mixed with peat and gravel. I have some in bark/sphagnum mixtures. they all grow and flower, the roots don't rot.
    At least, old roots do rot - they only live for maybe 4 years ( with good culture) shorter time with less good. After that they may rot, or more often go stringy.
    Keeping the roots good and preventing rotting depends on other factors too - strength of the nutrient mix , frequency of watering, air movement, light, .....
    Vanda roots are no different from other epiphyte roots, except perhaps thicker ( = needing a more open compost, more definite actual drying between waterings , etc ).

Similar Threads

  1. Can a phal survive without soil temporarily?
    By ihaveacup in forum Phalaenopsis ('moth orchid') Information
    Replies: 1
    Last Post: March 4th, 2012, 03:25 PM
  2. Will these cuttings survive?
    By rosie in forum New Growers: Ask the Senior Members
    Replies: 14
    Last Post: November 15th, 2011, 06:43 PM
  3. Could this one survive?
    By the dragonn in forum Phalaenopsis, Oncidium, & Intergenerics IN BLOOM
    Replies: 13
    Last Post: January 20th, 2008, 10:36 AM
  4. What orchid roots can do !!
    By Gilda in forum General Orchid Culture
    Replies: 6
    Last Post: November 4th, 2005, 06:13 PM
  5. Will this survive?
    By PhalPhreak in forum General Orchid Culture
    Replies: 5
    Last Post: September 1st, 2004, 03:43 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
OrchidTalk --An Orchid Growers Discussion Forum brought to you by River Valley Orchidworks. A World Community where orchid beginners and experts talk about orchids and share tips on their care, cultivation, and propagation.