Phal Moisture - I'm Confused

[Windy]

In some recent posts, it's mentioned that phals like to dry out between waterings. Yet, I've also read in the past that they don't like to be too dry...not like Cattleyas.

Which is right?

[King_of_orchid_growing:)]

Phals do need to dry out for a bit because of the way they're cultivated.

If you look at pics of the non-deciduous species in the wild, they're seen growing on trees in swamp forests or near the edge of rivers in tropical climates. They're almost always around water. But they're not sopping wet either. The trees hardly have any moss on them if any. The Phals are getting their moisture from the humidity in the air and the water the bark of the trees wick up. The roots are pretty much exposed to the air. This means that the moisture doesn't stay heavy because the water evaporates.

In cultivation, we may just be giving Phals a bit more moisture than how mother nature does it (especially when they're potted), so hence a bit of a dry out period to allow the roots to breathe.

Cattleyas grow on trees with very little to no moss as well. But they're not growing in swamp forests so it's not as wet. They're more dependent on the humidity and the rains than a more consistent moisture that wicks up from the tree barks. As you know, rains are rather inconsistent, that's what the pseudobulb is for (it's a modified stem for water storage during dry periods). Some are from cloud forests, but many aren't, hence they don't grow as wet. To complicate things more, some Cattleyas are lithophytes growing on rocks along cliff faces near watefalls, exposed to bright light, but they're still not growing in a habitat as wet as that of Phalaenopsis. This is because the rocks retain moisture in a manner closer to that of semi-hydroponics versus the more moisture retaining mosses.

I'm not going to over complicate the whole Cattleya deal, because it may be more than what you've asked about.

[Ross]

I grow mine in clear pots for two reasons: I can see the roots and when they turn white I submerge the entire pot to soak it for a couple minutes. The roots turn to green because they contain chlorophyll. The second reason is the chlorophyll. The pots are in the sun of a south window and the exposed roots then will help in the same way the leaves do to make food for the plants. Clear pots are sort of like cheating: I rarely overwater because I can see the bark and if it's wet, I don't water. Some folks here grow there Phals mounted for much the same reason.

[RosieC]

I think King has hit on the key here.

As far as I can work out, if the roots are able to breath sufficiently then they can be kept moist all the time. But generally because of the way we keep them in pots the easiest way to ensure the roots are breathing sufficiently is to let them dry out completely between waterings.

I do like Ross and use clear pots and when the roots turn silvery and the bark is dry I water again.

I've heard some people say their Phals do well constantly moist, better than if you keep drying them out, but I think that to do that you need a very very airy medium, otherwise the roots can't breath and are likely to rot.

I think mounted Phals can be kept more moist as the roots are out in the air anyway.

[Undergrounder]

It's confusing Windy because almost all orchids (and their roots included) don't live by any one specific rule. Yet just about everyone will 'tell you' what is best for orchids, and give you the 'golden rule' only because that's what they've been told themselves, and that's what they do.

The fact is, they grow and adapt well to a vast range of environments given their basic needs are met, and don't live by any one rule of watering.

For instance if you stick a Phal. in wet sphagnum moss, hydroponics or even a reservoir of water, it will grow roots that will happily grow into the water and live all their lives under water.

If you stick a Phal. on the side of a tree, it will grow roots that live all their lives in air with very little water (given a little extra humidity)

To illustrate the point, i have a dozen orchids growing in my backyard that are just attached to rocks.. the roots spread over the rock and get what moisture they can from the occasional rains. But down in my basement, i have the exact same kind of orchid growing in semi-hydroponics, with a vast, green root system that spends almost its entire life completely wet, and even completely submerged in water... same species, completely different conditions. They key is both plants have grown and adapted into their different environments and are used to it. Changing their environment, however, or swapping the plants from the rocks to the S/H or vice-versa, would kill the respective roots systems, and the plants would only start to recover after their new roots have grown into the new environment.

But, given the choice between both extremes, i would choose a method that gives them plenty of water. Studies have shown that Phals grow much bigger and flower better when given lots of water and not allowed to dry out.

If you're unsure about how to water your Phalaenopsis, inspect the old root system. If it is thick, fairly smooth, has lots of branching and is a nice white or green with bright green root tips, it will thrive with lots of water. If it's silvery, dry, rough, creased or papery with stunted tips, it will prefer dryer conditions, and only the fresh new root growth that grows from the crown will be able to handle more water.

[orchidsamore]

I am a commercial grower and as such try never to allow Phals to dry out. They dry occasionally without serious harm but the more they dry the slower they grow.

Last season I had 400 Phal Baldan's Kaleidoscope start as 1 inch pots (only a couple of months out of flask) and placed outside under shade cloth. The rainy season normally ends in October when they we put out but then rained every day until Christmas. They were in sphag and soaking wet every day.

I did not lose a plant in the rain and as soon as the rains stopped I started to have problems. I had to go to almost daily watering.

End result was extremely rapid plant growth and 250 flowered from Jan to April at less than 6 months old.

If they dry too much to where the roots stop growing, then the next watering is when rot begins.

Here is a study from Cornell Univ printed in the AOS bulletin. Showing the benefits of growing Phals very wet.

Frequency of Watering and the Growth of Phalaenopsis

[trdyl]

Jerry,

Thank you for that link.

[nutgirl]

How true this all is!

I subjected my phals to overly dry conditions for several years because of being told that you have to let orchids dry between waterings. They endured but never were happy. They would grow a leaf and some roots and maybe a spike.

Increased water has resulted in at least 3 leaves and vigorous root growth a season with much better blooming.

Maureen

[Windy]

Thanks for all the great info and the link. Now, putting it all into practice is the key.

One phal is my very first orchid (no name tag) and didn't even know what it type orchid it was until joining this board. But, at $2.50, who could turn it down? It had 2 leaves and a dead spike. I purchased clear containers for all my orchids I've purchased since, but when I went to repot this particular one, it had roots everywhere inside the pot and decided to leave it be. It now has about 8 leaves and a new one on the way, but it's never spiked.

I'd been watering it went it "looked" dry. My other 2 phals, I can see if there's moisure or not (and the roots).

All the advice given is truly very useful. Again, many thanks.