Phalaenopsis in water culture

[orchidsamore]

The reason you do not rot the roots in water is that decay is a living organism and requires moisture (water) and air to grow. There is no usable oxygen in water so decay does not grow.

Undergrounder is not correct when he describes water as 1/3 oxygen (actually 80% oxygen by weight weight of H is 1 and O is 8) but the oxygen is bound to the hydrogen molecules and is not usable to anything as oxygen.

There is dissolved oxygen O2 in water but it is not in a form that can be used by the decaying organisms, similar to the way we can not use the oxygen to survive while fish can.

[Undergrounder]

Originally Posted by orchidsamore

The reason you do not rot the roots in water is that decay is a living organism and requires moisture (water) and air to grow. There is no usable oxygen in water so decay does not grow.

There is dissolved oxygen O2 in water but it is not in a form that can be used by the decaying organisms, similar to the way we can not use the oxygen to survive while fish can.

I don't buy this explanation because there are plenty of anaerobic bacteria that rot roots that also live in water, and even aerobic fungi grow fine in water culture. I've grown mushroom cultures, the same kind you eat in supermarkets, in a mixture of sugar and water many times, it grows very well under water.

And how can it explain that roots grown in a dry environment, and then transferred into water culture rot and die within a matter of weeks?

[dabblin-n-orchids]

It is true that there are plenty of anaerobic bacteria and fungi that will rot the roots and roots that are not adapted to water will rot in a matter of weeks. But it appears that for some reason a thick layer of algae will prevent the growth of anaerobic bacteria and fungi. and if roots grow into water they grow noticeably differently and are adapted to being completely submerged and it would stand to reason that if you placed them in another media besides water they would die.

[Wrebbitrocks]

hmmm. all those responses are very helpful. i think im just gona keep doing the vase culture for now. i dont think i want to risk the few roots my phal has to finish dying.

[Undergrounder]

Originally Posted by dabblin-n-orchids

It is true that there are plenty of anaerobic bacteria and fungi that will rot the roots and roots that are not adapted to water will rot in a matter of weeks. But it appears that for some reason a thick layer of algae will prevent the growth of anaerobic bacteria and fungi. and if roots grow into water they grow noticeably differently and are adapted to being completely submerged and it would stand to reason that if you placed them in another media besides water they would die.

Completely agree with the second point, but the orchids i have in water culture (well, roots that have escaped into the reservoir at least) do so in water that doesn't have any algae, it gets cleaned regularly. I think algae might re-oxygenate the water, which is something that helps if you don't change the water regularly, but i haven't heard a reason to see why it would stop pathogens growing directly.

If there is an effect though, i think it might be that orchid roots need oxygen to produce their anti-fungal defenses. And when oxygen runs out in the water, the pathogens already in the water are able to attack the roots easier. Regularly replenished water, or water oxygenated through other means (including algae) might just keep roots healthy enough to resist pathogen attack, making it look like well-oxygenated water stops roots rotting. But that's just my theory.

I still agree that it's the specialised root structure in 'water' roots that somehow makes them able to survive submerged.

[dabblin-n-orchids]

i can completely see how the oxygenation provided by the algae would help. hence killing anaerobic bacteria and giving the roots the necessary oxygen. very good insight.
i remember hearing that when "normal" orchid roots are submerged they shut down and stop absorbing water. i don't know if this is accurate but it would explain the structural differences of roots growing submerged.
p.s. I LOVE ORCHIDS. they never cease to surprise me........

[Brookpoint]

Originally Posted by dabblin-n-orchids

i can completely see how the oxygenation provided by the algae would r hence killing anaerobic bacteria and giving the roots the necessary oxygen. very good insight.
i remember hearing that when "normal" orchid roots are submerged they shut down and stop absorbing water. i don't know if this is accurate but it would explain the structural differences of roots growing submerged.
p.s. I LOVE ORCHIDS. they never cease to surprise me........

For hours I have been glued to OB reading all the posts on water culture. Many thanks to all of you for your information and your kindness in sharing it with all of us. I am going to give it a try and see if I can be successful with wc.
I am spending entirely to much time on this website, but ohhhh I love it.
These cold temps we are having in Fl at this time are making it difficult for someone like me with no greenhouse that grows outdoors in my pool cage all year. I should say all year except when we are having nights in the 30's. They (the chids) are in the house here, there , and everywhere. We may have to move out if this weather doesn't break. I know all of you in the frigid North are really feeling sorry for me. Oh well, it seems all I do is spray and water to keep a little humidity present. And then in the summer we die from the humidity. It is still a great orchid growing life.

[greenbean]

I just learned some things last semester that may help piece the puzzle together. I think that, in addition to oxygenating the water and thereby making the roots healthier and better able to resist pathogens, the algae helps to block access to the roots. In soil there are fungi that form protective sheaths around roots, effectively blocking pathogenic organisms from accessing the roots. Perhaps the algae is performing a similar function. Still, the oxygenation is definitely key. My wc orchids did not do well until I grew a decent supply of algae in their containers and provided enough light to see the algae forming bubbles. And even then I've had to disinfect a couple of them after some sort of infection got into the water.

And orchid roots generally are hindered to some degree by a drastic change in media. Since switching to pure water is rather more drastic than other changes, the effect is more pronounced. It's also easier to see because they are growing in a clear container.

[Undergrounder]

Originally Posted by greenbean

I just learned some things last semester that may help piece the puzzle together. I think that, in addition to oxygenating the water and thereby making the roots healthier and better able to resist pathogens, the algae helps to block access to the roots. In soil there are fungi that form protective sheaths around roots, effectively blocking pathogenic organisms from accessing the roots. Perhaps the algae is performing a similar function. Still, the oxygenation is definitely key. My wc orchids did not do well until I grew a decent supply of algae in their containers and provided enough light to see the algae forming bubbles. And even then I've had to disinfect a couple of them after some sort of infection got into the water.

And orchid roots generally are hindered to some degree by a drastic change in media. Since switching to pure water is rather more drastic than other changes, the effect is more pronounced. It's also easier to see because they are growing in a clear container.

I'm sure that algae helps, but again, i really don't think it is the key. The Phals i grow that are effectively in water culture do it in clean water, with no algae buildup. And i have seen reports of success with water culture where people change the water every week.

So i think it is important to either: refresh the water regularly to replenish the oxygen, or allow algae to buildup to provide the oxygen. In my opinion it is some kind of structural difference in 'water roots' that allows them to survive submerged. And this is evidenced by the fact that roots grown in dry conditions usually rot in water, while new roots allowed to grow into water usually survive.

[Shawna]

hello
I am new to this forum. With out reading all of the posts could someone tell me if I can do water culture with the sunlight from my East & South windows or will the water get to warm? Mostly Catts. In the beginning how often would water be changed? I have some KLN root soultion & Dyna Grow fertilzer. This would be my first experiment doing water culture. Thanks