DIY Large humidifier for orchids (or anything else)

Last week my humidifier finally died. It had been getting very corroded and had lots of mineral deposits but it was really hard to clean. I think the brand was Holmes. Anyway, I had an ultrasonic fogger sitting around that I picked up on clearance from the craft store so I decided to build my own. I wanted something easy to fill and I wanted it to be easy to take apart and clean. The old one was awkward to fill and leaked on the floor occasionally and would become covered with slimy pink algae in just a few days. This picture is the almost final result (I added a screen over the intake fan and wrapped the cords up.)

My parts list:
-ultrasonic fogger with power supply
-old computer fan with power supply
-5 gallon bucket with lid
-ABS pipe and fittings:
--1 foot of 2" pipe
--2" to 3 inch adapter (big enough for the computer fan to fit in the larger end)
--2" straight coupler
--2" threaded coupler x2
--2" - 22° elbow

-4" threaded nipple (plastic)
-Fiberglass driveway marker
-cable cover
-closed cell foam
-rubber band
-plastic screen
-Timer and extension cord



This message was edited Mar 3, 2012 1:29 PM

The first step is to mark where to cut holes in the top. I used a marker to trace around the pipes.

Then I cut the holes with a hole saw and trimmed them up with a razor blade knife. The plastic was pretty soft so they could probably be cut with the knife alone. Then I pushed the smooth side of the threaded couplers through the holes and threaded the plastic nipple through the small hole. This is the inside of the lid.

Next, I pressed the 2" to 3" adapter and the straight coupler onto the parts of the large couplers that stick through the top. I didn't glue anything because I want to be able to take it apart and clean everything.

To make the outlet taller for my higher shelves, I added a one foot long section of pipe and capped it with the elbow.

I cut the fiberglass rod to the same height as the bucket and stuck it into a piece of closed cell foam. This is the water level indicator. It slides through the plastic nipple. The reason for using the plastic nipple is that with a simple hole in the lid the bottom of the rod can drift to the far side of the bucket and get jammed. This keeps it moving up and down smoothly.

The fogger has to float just below the surface of the water. If it's too high the safety switch will shut it off, too low and it won't make much mist. Special floats can be purchased from ebay or the craft shop but I cobbled together one from pieces of extra plastic and foam.

Oops, almost forgot this part. Make a small notch in the side of one of the larger holes and pass the cord for the fogger through the hole and snap it into the notch before placing the couplers through the large hole.

I trimmed away the plastic on one side of the fan so it would fit in the intake side.

Fan in place. To protect the wires I slid them into a plastic sleeve.

I plugged both the fogger and fan into an extension cord and then into a timer. The timer runs in the morning when the sun shining through the doors and the furnace is usually on, and then again for a little while in the afternoon.

WOW! Thank you for the instructions and setup! I've had issues with humidity here as well (especially this past summer!) so my orchids always look a little peaked and their roots aren't as happy as they should be. This looks like a great way to manage and I'd finally be able to use my shelf system appropriately! :)

Hi Carey, good luck on your project, I hope it keeps your orchids happy. I've only been using ours for a couple of weeks now so I'm not sure if the orchids look perkier yet. I can see the mist falling down through the plants and it definitely puts more mist in the air than the old one did.

I forgot to add that you can buy the foggers on ebay pretty cheap and they have a replaceable disk so they can be repaired much more easily. Total cost on mine was about $20 but I had some of the parts laying around already that would add another $20 to $30.

This is very nice of you to post such a good tutorial, Kaitlan. Thanks. You didn't mention what your humidity is normally or by how much you have boosted your humidity. Your humidifier appears to be pointed at a rack in one space. How much area are you actually humidifying? Did you measure humidity before building your humidifier? Are you measuring your humidity now to compare? What kind of orchids do you grow or, what kind of other plants do you have in the mix that need the humidity boost? I see you're in Nevada so maybe your humidity is normally very low for growing houseplants? How is your new system working?

Our normal winter humidity is less than 10% and sometimes so low our hygrometer won't read it at all. The humidity in the living room, about 10 feet away, is around 30 to 40% now. Right now it's using about a gallon and a half per day and it can hold about 4 gallons max so it only needs to be filled every couple of days. It's a good use for the water we have to run to get hot water in the kitchen.

The output is pointed at the shelves of orchids but it's open to the dining room/kitchen/living room so the mist dissipates pretty quickly. The orchids are a motley assortment of common hybrids (phals, paphs, oncidium hybrids) and many of them were given to me because their owners were slowly (sometimes rapidly) killing them. There are a few other random plants stuck in there too.

The humidity also helps keep the wooden flooring from shrinking and leaving gaps, and reduce my asthma, and control the static electricity build up.

It seems that the moisture output could be easily controlled by changing the output of the fan or the amount of time it runs, or even hooking up the power to a humidity sensor with a switch.

Do you realize your low humidity is extraordinarily low? Even a Florida or Georgia winter puts the humidity at 30-40%. We have humidifiers on each of the three floors of our heating systems and they boost the humidity another 10-20%. I keep the small (tiny) solarium where I've got mixed plants at at least 50% and the orchids in the greenhut never go below 60%. It is normal for the humidity in this tiny space to exceed 80% every day. I love to go in there and breathe the air when it's 82% humidity and 74 degrees. The orchids love breathing that air too.

What orchids do you think are benefiting most from the humidity? Some orchids do okay in relatively low humidity with water and others seem to do best with little water but need high humidity. I use an old Springfield temperature/hygrometer analog thermometer. There are really cheap digital versions now.

You have raised a very important point about growing orchids well. If you have a few as houseplants maybe it's not important but if you are trying to collect plants in an indoor space you have to know the humidity. I could or should make the "have to know" big and bold and important. It is as important, if not more important, than the temperature. Many orchids are more temperature tolerant than humidity tolerant. People don't understand that blowing a few mistings out of a bottle or hanging an orchid over an aquarium may not make up for what that orchid requires.

Kaitlian - Thanks! I'd prefer to find the fogger locally since I can always return it should it fail or not meet my needs. Our weather was very close to yours this past summer with the temps so high and the humidity barely cracking 10%. Our house has old aluminum windows and is really drafty so humidity is a real problem for us. I can easily sell this to DH since I can push the angle how much his cigar humidor would benefit. ;)

Laurel - Central Texas is normally around 30-40% during the summer, but last year was extremely bad with the daily humidity falling into the single digits. Our winters are pretty mild, but the humidity is usually in the 20% range.

I grew up in Oregon so moving to the desert has been very trying at times. One clogged emitter on the irrigation system in August and I could loose a nice plant in a day or two. The dryness is pretty tough on skin and sinuses too. My husband grew up here and he complains about the humidity every time we travel.

I would run the humidifier more but the leaves nearest the output get rather wet and I don't want them to rot from being wet too long. Someday I may get into growing fancier orchids but only if we move to a less harsh climate or I get a greenhouse that big enough to stay warm when it's 2° at night. But we're kind of stuck here as long as my mother-in-law's horse is alive (long story).

We have one of the digital weather stations but it's not fancy enough to record throughout the day so I usually just get high and low readings. In the summer the orchids are in my small greenhouse which is hooked up to the irrigation system and get's misted a couple of times a day. The misting and sheer number of plants keep the humidity pretty high. With the shade cloths up and the windows open the greenhouse is usually cooler and moister than outside during the day and warmer at night. In the spring and fall I go for maximum heat gain during the day so that it will stay warm overnight.

I sure admire your tenacity in growing orchids in the desert, Katlian! All that humidity you're making is doing you as much good as the plants.

We moved to Salt Lake City from Vancouver, Canada and lived there 21 yr. before moving to Florida. Similar dry, dry air there, plus terrible air pollution when the inversion sets in in the winter. We put a big, expensive humidifier on our furnace plus a fancy electronic air filter, and still suffered all kinds of bronchial woes while we were there. No more of that since we've been here - nice clean, humid air.

Our kids still live there, and my daughter recently asked me if she should try an orchid. I said 'maybe' but it would take a lot of determination and diligent care. Since she works 10hr. days 4 days per week, I hope she sticks to dry air lovers.

Well, kudos to all of you who are climate challenged and growing orchids. Having grown up in S. FL, I have always lived in a very mild climate. I am somewhat clueless regarding the challenges climate extremes bring. I still can't figure out how people get to work where it snows. lol As for the horse...we had horses up until five years ago. Needless to say the equine yard art put the kabosh on my orchid hobby.

Even 10 mi. from the ocean, our humidity has been in the teens during the day, but goes to the 80% at night. It does vary here though, depending on the Pacific temps. I have tried the misting system outside during the summer, but it does over wet the plant, so I may try a humidifier to replace the space heater, come summer. LOL! During Dec. we had fog most nights, now it's winds. Does that explain why I haven't been posting orchid pictures?

Oh my Carol! At least here it is usually just dry dry dry with a few days of rain peppered in.

Carol, I think you're getting some of our cold, dry air blowing over the mountains. We've had nothing but cold, dry east winds for two months now and no snow. I hope I will be able to water my garden this summer.

That makes two of us! Last year we had a glut of water, and no place to store it. This year looks like water restrictions, so far.

But Carol, how's the greenhut doing? Is it up and going enough for you to notice a difference?

Well, with the temporary walls and a space heater, I'm able to keep the temps up. I leave the door open during the day for air movement, but can't do much about humidity at this point. I'm getting spikes and buds, so I'll just have to wait and see. I'll probably have to add shade cloth when the sun gets higher. It will remain a work in progress, no doubt.

I have a small Vornado, stationed under a glass table, running on low 24/7. The air movement is perfect. We took the greenhut apart this fall to lay 6 mil plastic over the decking and under the indoor/outdoor carpet. Don't know what I was thinking when we put carpet down on top of a cedar deck with no vapor barrier. The trapped moisture from watering has raised the humidity by about twenty percent. If it's too humid I can open the door into the solarium and the windows into the family room. The extra moisture is nice in this weather. The humidity is no problem in warmer weather because the doors are open with the fan running. I catch some of the excess water in large catering pans under the shelves or on the floor under the Vandas and pour it off into a bucket to water houseplants.

Whatever you do be timely about the shade cloth. That's how so many of my orchids were so badly damaged last year. I've used nylon window screening on both the greenhut and the little slat house but am about to come in to some aluminet. The aluminet not ony shades but reflects heat.