Phal - issues with fertilizer, pots, and environment, mainly - just issues...

[D_novice]

Originally Posted by jkofferdahl

Humidity trays are pretty much useless. I use them to catch water run-off, but not to raise humidity.

With all due respect to Mr. Offerdahl, whose orchid-growing results speak for themselves, the topic of humidity trays has been passionately and thoroughly bandied about in other threads in this forum. Some esteemed OB participants equate them with doctors recommending smoking for its health benefits!....

This topic is of interest to me, since I grow in windows, don't have much of a greenhouse, and own several humidity trays.

For getting plants and a room from 30% humidity to 65%, there's no question a humidity tray can't do it by itself, esp. compared to a humidifier, mister, misting by hand, etc.

However, I think one of the problems with humidity trays is the lack of surface area in which the water can evaporate into the air. A flat water surface, covered with a thick plastic grate that limits air movement, and in which the water is probably covered with a thin film of who knows what that "tightens up" the surface tension, is a different animal than a dish or tray or humidity tray containing a porous mineral substrate live lava rock or other pumice, gravel, coarse sand, or even expanded leca clay in which the water can easily evaporate.

I have been playing with my humidity trays, and misting and some cheap hygrometers. The humidity is highest on top of the damp gravel, and still better than no tray + gravel at the level of the top of the plant (so the undersides of the leaves, and the lower leaves, are getting a benefit of increased humidity.) Misting is still best, but it isn't passive, and machines are a whole different order of complexity.

So - I would recommend against an absolute (hyperbolic?!) statement "humidity trays are useless and do nothing", but rather (like so many things) "it depends". And it depends on a million different things, like what plants, ambient room humidity, what else you're trying to help with humidity, etc.

And, for those who think the AOS publications department hasn't read anything or grown any orchids in 5 or 6 decades, even some - gasp! - growers with sterling reputations still recommend this outdated () old-fashioned trick:

Humidity: 50% to 80% relative humidity can be provided by placing the pots in the tray filled with 1" to 2" of gravel, and 3/4 inch of water. The evaporation will increase the humidity around the plants.

Fox Valley Orchids, Culture Instructions

	Mistking Looking for a misting system? Look no further. Automated misting systems from MistKing are used by multitude of plant enthusiasts and are perfect for Orchids. Systems feature run dry pumps, ZipDrip valve, adjustable black nozzles, per second control! Automatically mist one growing shelf or a greenhouse full of Orchids. See MistKing testimonials

[orchidsarefun]

Grouping plants close together is another effective way of raising ambient humidity. I find it effective.

Sent from my LG-H901 using Tapatalk

[jkofferdahl]

Originally Posted by D_novice

With all due respect to Mr. Offerdahl, whose orchid-growing results speak for themselves, the topic of humidity trays has been passionately and thoroughly bandied about in other threads in this forum. Some esteemed OB participants equate them with doctors recommending smoking for its health benefits!....

This topic is of interest to me, since I grow in windows, don't have much of a greenhouse, and own several humidity trays.

For getting plants and a room from 30% humidity to 65%, there's no question a humidity tray can't do it by itself, esp. compared to a humidifier, mister, misting by hand, etc.

However, I think one of the problems with humidity trays is the lack of surface area in which the water can evaporate into the air. A flat water surface, covered with a thick plastic grate that limits air movement, and in which the water is probably covered with a thin film of who knows what that "tightens up" the surface tension, is a different animal than a dish or tray or humidity tray containing a porous mineral substrate live lava rock or other pumice, gravel, coarse sand, or even expanded leca clay in which the water can easily evaporate.

I have been playing with my humidity trays, and misting and some cheap hygrometers. The humidity is highest on top of the damp gravel, and still better than no tray + gravel at the level of the top of the plant (so the undersides of the leaves, and the lower leaves, are getting a benefit of increased humidity.) Misting is still best, but it isn't passive, and machines are a whole different order of complexity.

So - I would recommend against an absolute (hyperbolic?!) statement "humidity trays are useless and do nothing", but rather (like so many things) "it depends". And it depends on a million different things, like what plants, ambient room humidity, what else you're trying to help with humidity, etc.

And, for those who think the AOS publications department hasn't read anything or grown any orchids in 5 or 6 decades, even some - gasp! - growers with sterling reputations still recommend this outdated () old-fashioned trick:

Humidity: 50% to 80% relative humidity can be provided by placing the pots in the tray filled with 1" to 2" of gravel, and 3/4 inch of water. The evaporation will increase the humidity around the plants.

Fox Valley Orchids, Culture Instructions

Dan, you're one of the last people on the OB with whom I would choose to disagree. Sadly, I must.

I'm afraid I still need to speak to the futility of humidity trays, with all respect given to those who appreciate them. The amount of water necessary to raise the humidity of a standard room in a house is significant when the goal is to raise it more than a few percentages. The evaporation rate from a 18 x 9 inch tray might slightly raise the humidity an inch above the tray but that is going to rapidly dissipate, and by the time you arrive at the top of a 4" tall pot it's dispersed. Adding stones, gravel, sand, or whatever may increase the surface area but still isn't going to be enough to make an effective increase in evaporation, and thus humidity.

As an experiment, take the tank of an ultrasonic humidifier. Mine holds about a half gallon. For me to increase the humidity in my plant room from 30% to about 65% I run the humidifier on high and it disperses all of the water in about 8 to 10 hours. If I empty the same tank into a humidity tray most of the water is still in the tray a couple of days later. Obviously the humidity isn't being adequately raised by a humidity tray if not enough water evaporates.

Measuring the humidity right on top of the tray is going to give a false reading. Right at the tray you'll have the highest concentration of evaporate, while if rapidly dissipates even inches from the tray. By the time you measure humidity even four inches above the tray you'll see a significant drop off. Yes, if the tray is covered by plants and those plants' leaves are above the tray, they will get a bit of extra humidity, and the leaves may slightly hold humidity to the tray, but again that's not going to be significant.

Now, add to this that as you raise humidity you're also going to want to raise air movement (unless you enjoy dealing with fungal issues). Most growers use fans. The air blowing from these fans is going to push that wee bit of extra humidity from the tray out into and through the room and away from under the plants. Poof, you've just more than lost any slight advantage gained from the tray. Think of it as using a small butane lighter: if you touch the flame it's obviously going to burn you but it's not going to cause the room temperature to measurably rise.

To get a reasonably accurate idea of the humidity around your plants put your hydrometer several feet away, out of the breeze from the fans, from where your plants are growing. That way you're measuring more what's truly in the air of the room rather than just inches from your plants.

	Mistking Looking for a misting system? Look no further. Automated misting systems from MistKing are used by multitude of plant enthusiasts and are perfect for Orchids. Systems feature run dry pumps, ZipDrip valve, adjustable black nozzles, per second control! Automatically mist one growing shelf or a greenhouse full of Orchids. See MistKing testimonials

[Dollythehun]

Ouch. I use a humidity tray (s) and in my small "orchid jail" I did notice a slight increase in humidity with a tray and leca. Granted, it was only a few points but, it got me up to 50%.

[jkofferdahl]

Originally Posted by Dollythehun

Ouch. I use a humidity tray (s) and in my small "orchid jail" I did notice a slight increase in humidity with a tray and leca. Granted, it was only a few points but, it got me up to 50%.

From where are you measuring? And as I said, you'll see a VERY slight bump (a few points isn't a surprise depending on where you measure it) but fans and dispersion are pretty much going to eliminate it.

[orchidsarefun]

I don't use fans. I tried once and the increased air circulation caused bud blast. In low humidity environments fans disperse humidity rapidly, drying out the environment quicker. There is no point ? However I always maintain that you must do what works for you and that involves experimentation with a lot of different things. Sometimes success with orchids is more of an art rather than a science.

Sent from my LG-H901 using Tapatalk

[Ray]

The ideal air movement around your plants is gentle and tumbling, not a breeze, and certainly nothing that would cause bud blast. The idea is to prevent stagnation anywhere around the plants.

[jkofferdahl]

Originally Posted by Ray

The ideal air movement around your plants is gentle and tumbling, not a breeze, and certainly nothing that would cause bud blast. The idea is to prevent stagnation anywhere around the plants.

Exactly. I don't use box fans, I use small, "personal" fans. These keep the air light and moving without creating a wind. I've experienced no bud blast at all since I've been using them but also have experienced no fungal or bacterial issues, or, for that matter, insect troubles. Gentle air movement helps the roots as well, by allowing more air to get to them. If there was more natural air movement inside my house I'd consider turning off the fans, but not with the air stagnation typical in a house.

[orchidsarefun]

Thinking further on this I would clarify that although I don't use fans at all, there is quite a bit of air circulation. Heating, cooling, people and pets all contribute to circulation. Plus a limited time when I am able to open windows and doors.
I have a whole house humidifier which activates when the furnace operates, and this does a fairly good job of keeping humidity in the 40's. Despite this I still have 3 portable humidifiers which run 24/7 in 3 rooms. I have noticed that certain orchids prefer higher relative humidity and grow vigorously if you can match these requirements.

Sent from my LG-H901 using Tapatalk

[estación seca]

Originally Posted by jkofferdahl

That quote's from "Process and Reality" (thus the PR), but I'd say his lengthy CV was pretty good proof.

(I could say he only had to work it out when he was constipated. But I'd not indulge in such low humor.)

Maybe I'll need to pick up a copy of Princess and Reality.