Humidity

There are many methods that try to elevate the humidity around the plants, but few are very effective. Grouping plants close together helps a little bit, adding humidity trays helps a little more (but hardly enough to be worth the effort in my opinion). Misting does very little for raising the RH for any marked amount of time. I actually rarely mist my plants, I feel that it is too risky, an invitation to trouble with mould.

If you want results raising humidity, you really need to consider a humidifier. You run the humidifier at night when the plants open the cells to breathe and can benefit from the added humidity. There are basically two kinds of humidifiers, cold air and hot air humidifiers.

Cold air humidifiers

The three most common cold air humidifiers are:

Evaporation (or wick)

The easiest system to run, consisting of a water tank, wick and fan. The wick absorbs water and the fan blows air onto the wick, the water evaporates and the humid air is blown out into the room, raising the humidity.

Review:

Pros: fairly inexpensive to buy and easy to operate
Cons: loud when running, moderately efficient

Impeller driven

About the same idea as the evaporation model above, but with a spinning disc or propeller that is breaking the water droplets into tiny droplets which creates a fine mist. You can actually see the mist when it comes out of the machine and it usually runs a little quieter than the evaporation models.

Review:

Pros: fairly inexpensive to buy and easy to operate
Cons: loud when running, moderately efficient

Ultrasonic

This system use ultrasonic sound waves to vibrate the water converting it into a cold fog that you can see.

Review:

Pros: easy to run, very effective, silent running, very efficient
Cons: a bit more expensive

Warm air humidifiers

My growing areas

The growing room

At first I chose an inexpensive cold air impeller driven humidifier, but thankfully that one broke down after about 9 months. I say thankfully because it was not very effective and it was very loud to run- Luckily I got to replace in under warranty. I replaced it with a 5L capacity ultrasonic cold air humidifier instead (Honeywell HH200E4), and I am quite pleased.

Since the cool fog kind of blows out of the nozzle then immediately fall I needed a rig to bring the flow further up in my growing window then have it gently fall down on the 3 levels of orchids below so I get better coverage and at the same time raising the over all RH in the room. But I do not wish to keep the 5L water container for the humidifier 3 meters up in the air, so I built a chimney using regular PVC pipes and a cheap funnel. Three holes drilled in the pipe running across the top and the fog flows down the top like magic..! Read about the installation here.

In my small growing room, with the door closed, I get about 70% humidity at night. I keep it on a timer running the unit every other half hour for a half hour at a time every night – and once again at noon for good measure.

Photos

Warm vivarium

In the warm vivarium I used to have 3 humidity trays on the bottom filled with water to help raise the humidity. But after filling the space with orchids I do not have to keep the humidity trays anymore, they serve as collection trays instead. Thanks to the amount of plants and the humid growing media, humidity hovers between 85-95% inside. A temperature and hygrometer tells me all is working like it should. I spent about $15 on one that is showing both humidity and temperature, plus save the high/low value so that you can keep track of the measurements.

PS! See all those hard water stains I used to get on the vivarium glass? A pain in the, well, you know what. This was fixed when I finally got a reverse osmosis filter. The filtered water does stain the glass in this way. A very nice added benefit.

Photos

Cool vivarium

In the cool vivarium I use the same Honeywell 5L capacity ultrasonic cold air humidifier, and use PVC pipes to make another “chimney” for the fog. I pipe it into the viv. through a hole in the side. It is connected to the same times as the humidifier used in the room. Humidity hovers around 85% inside the viv. A temperature and hygrometer tells me all is working like it should. I keep it on a timer running the unit every other half hour for a half hour at a time every night. During the day I keep in on a longer interval, on for 15 minutes with an hour in between.

Photos