Afternoon watering... a disconnect

[ChrisFL]

So, for many orchids like bulbos, they come from areas that get predominantly rained on during the mid afternoon.

This is considered a universal no no in growing orchids. Everyone seems to be of the consensus that you water in the morning and let dry out during the day.

Why the disconnect? I've been in rain forests at a variety of altitudes and things are still SOAKED at night, despite a temperature drop.

What is it about being in "captivity" that makes this bad for plants?

 

[newbud]

I water when ever. All different times of the day because I'm not very disciplined at all. When ever I feel the orchids calling me, I water. Sometimes that's 11pm, sometimes 6am. Phals; everything. I do try to blot out the phals if water gets in the crowns because of all the fear people have invoked in us. I've yet to see any damage or problem with this style of watering. My 2 cents.

 

[Rick]

Chris

This was one of the "myths" that got me going on the low K stuff.

In my GH plants raised on low K high Ca/Mg don't die from rots when watered (or fogged on) during the afternoon or night.

The old reasoning was that some kind of magic airflow condition occurred in real rainforests at night to prevent "stagnation" of the water on the plants, or real rainforest rainfall is so strong that it flushed out pathogenic bacteria away from the plants.

My premise (that was supported in agricultural literature) was that high K leaf tissue concentrations (subsequently causing Ca and Mg deficiencies) reduces plant immunity to disease.

The novel part of the low K study was that uptake of K in epiphytic plants is active and not passive. And given the access of unlimited amounts of K in the environment, most plants will grab as much as they can until toxicity occurs.

 

[Candace]

Watering at night is not a 'no no' during the warmer months. At least I've never heard that. Typically, I don't water at night because of my schedule, but it has nothing to do with the plants. They must conform to my life and routine or get out:>

 

[Rick]

One exciting piece of documentation was given to us by Stone (in Australia) which was a study of leaf tissue nutrient concentrations in in situ Panamanian epiphytes.

Maybe not so surprising, but exciting, was that the minority epiphytic species that had high K leaf content were ant associates (i.e. cultivated like humans cultivating corn).

Potassium is primarily for sugar production in plants. We give corn high K to give is big sugar/starch filled ears of edible seeds. But corn is also a short lived annual that gets replanted every year.

The plants that ants cultivate have all kinds of little nectaries all over the plants to feed the ants (sugar). And maybe in a similar way, a lot of these "ant plants" tend to be semi deciduous, with explosive seasonal growth followed by a major seasonal leaf drop.

 

[ChrisFL]

Very interesting Rick.

Most people will pull their hair out reading this, but I don't fertilize at all. Ever. I have an intake fan that pumps fresh air through my system every 45 minutes for a 15 minute duration.

And boy let me tell you, there ain't no magic airflow in tropical west Pacific rain forests. I honestly think the all out airflow needs of a lot of species have been greatly exaggerated. I think exchange with fresh air (personally) is MUCH more important that just air blowing around.

 

[ChrisFL]

In fact, a lot of more delicate Bulbo spikes will blast in any air movement.

 

[Rick]

Very interesting Rick.

Most people will pull their hair out reading this, but I don't fertilize at all.

Yes I also potted up a handful of plants in a shredded leaf litter mix from leaves in my front yard, that get NO supplemental feeding.

At the most we are looking at less than a year to six months, but so far they are growing just as good if not better than fed plants sitting next to them.

There is also a little old German lady in our orchid society that has been growing since the 1950's. Ran a corsage/cut flower business back when big Catt flowers were popular. She never has and never will give supplemental feeding. I've seen her greenhouses, and its full of huge specimen plants that have grown into the benches!

 

[Lanmark]

There could be many reasons why indoor orchids often suffer from late-in-the-day waterings:

• 
  Atmospheric movement and air exchange is generally much better outdoors in the wild than it is indoors.

• Hard-grown "wild" plants are often much tougher than pampered indoor plants, having been exposed to all sorts of adversity right from the very start.

• "Wild" plants result as a product of natural selection or "survival of the fittest" instead of being offered the artificially-equal opportunity to start and thrive in a protected, sterile, agar environment before being manually selected for cultivation based on human esthetics.

• The isolation of plants "in captivity" can exacerbate an infestation or infection by the very exclusion of otherwise naturally-occurring defenses and controls.

• What Rick said about potassium.

 

[Hera]

Another thought, plants in the wild certainly don't look as picture ready as our home grown ones. Most pictures of wild grown at least have mechanical damage and I would make the assumption that the ones affected by disease quickly succumb and rot away. We tend to expect that every leaf on a plant should be shiny and healthy. While it is a good indicator of good culture, wild plants never show absolutely no damage. A season of poor growing conditions in the wild would have a definite effect. That being said, even with good air movement in a greenhouse we are moving around the same volume. Spores of mold, fungus etc, and critters and their eggs are concentrated in a small space. I agree that wild plants are hardier as well.

 

[Rick]

I think there's a big difference between a bit of mechanical damage hear and there in wild plants, and complete dead rotted plants in the GH.

We get to see more and more in situ pics of wild plants on this site, and lots of them are superior to greenhouse plants even with a few leaves out of place.

I spend plenty of time at shows and judging centers (where we should be seeing the cream of the crop), and high quality unblemished specimen plants are just as rare as perfect plants in the jungle.

 

[Stone]

Having grown orchids both outside and in a glass house, I can say that there is a WORLD of difference in air movement. Even on an apparently still day, there is still more air moving than inside the g/house with 5 fans going flat-out! Let alone a sight breeze or wind. It would cost me a fortune to move that much air 24/7, so I water between morning to miday unless its a warm and windy night outside and I can leave all the windows open.

 

[Paul Mc]

I have to say though, Ive read the same about watering your outdoor plants. Only do so in the morning to early evening. For the same reasons people have said Bout why to water orchids at that time. Does that have truth then?

 

[gonewild]

One reason not mentioned is that orchids in the rainforest are not growing in pots or mounted on "unnatural media". Another is that it does not seem to benefit the plants to water them at night when growing under artificial conditions and it can contribute to serious problems.

 

[gonewild]

I think there's a big difference between a bit of mechanical damage hear and there in wild plants, and complete dead rotted plants in the GH.

We don't really see too many "rotting" orchids in the natural habitat. Probably because when a plant does get an infection it is decomposed within a short time.

We get to see more and more in situ pics of wild plants on this site, and lots of them are superior to greenhouse plants even with a few leaves out of place.

That is because the photographer selects the beautiful plants to photograph and shuns the ragged ones.

I spend plenty of time at shows and judging centers (where we should be seeing the cream of the crop), and high quality unblemished

All plants in the jungle are perfect! :drool:

 

[Stone]

I have to say though, Ive read the same about watering your outdoor plants. Only do so in the morning to early evening. For the same reasons people have said Bout why to water orchids at that time. Does that have truth then?

In summer I water the shadehouse plants just before sunset every single day and they're are always dry (at the leaf) by morning. Mind you that our summers have less rain and lower humidity.

 

[Rick]

it can contribute to serious problems.

Lance that was the point that started this thread.

How come only "serious problems" happen in GH when watering at night, but jungle plants survive (barring some "mechanical damage")?

Orchids have survived in jungles for millions of years getting rained on at all hours of the day, but the way individuals talk (such as "contributes to serious problems") suggest that you can loose a whole GH of orchids in a week by night watering.

I have a fogger set to a humidistat in my GH that generates considerable fog whenever the humidity drops below 70%. I know it comes on at night at times because I've been in the GH at all hours checking things out. But over the last 10+ years I've never had any all out epidemics. And since going K-lite I'm having very much fewer individual plant problems.

 

[emydura]

Lance that was the point that started this thread.

How come only "serious problems" happen in GH when watering at night, but jungle plants survive (barring some "mechanical damage")?

Orchids have survived in jungles for millions of years getting rained on at all hours of the day, but the way individuals talk (such as "contributes to serious problems") suggest that you can loose a whole GH of orchids in a week by night watering.

I have a fogger set to a humidistat in my GH that generates considerable fog whenever the humidity drops below 70%. I know it comes on at night at times because I've been in the GH at all hours checking things out. But over the last 10+ years I've never had any all out epidemics. And since going K-lite I'm having very much fewer individual plant problems.

I think what Lance was saying is that there are no actual benefits from watering the greenhouse at night but plenty of potential problems. I don't have anywhere near the rot problems I use to have but I wouldn't tempt fate by watering at night. I don't see why I would want to. CAM plants would be different but Paphs aren't one of those.

 

[ChrisFL]

Let me also back up here. I see "at night" being tossed around. I'm talking about watering between 3-5 PM, when most rainstorms fire off in the Maritime Continent.

If I water during the morning and have plenty of air exchange, the plants dry out. A lot of people consider that ideal, I don't based on what I've seen in the wild for species like bulbos. Leaves maybe, but not roots.

 

[goods]

I grow in two different tanks, a regular terrarium and my modified fridge. I try to follow the old rule of watering only in the morning to let things dry out, but that wasn't possible for me last semester. My classes on Tuesdays and Thursdays started before the lights came on, and I wasn't home until 4ish. Since most of my plants are mounted, I watered everyday. Aside from my finicky B. nitidum, none of my plants showed any ill effects to the later watering. My terrarium has a ~1" opening in the top for air exchange and two computer fans, and the fridge has a small hole for minimal gas exchange but has heavy air movement inside.

I tend to not fertilize and use mostly rain or RO water when watering.