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Poll: Highland Nep. Cooling Methods


Not Growing Up!
I know this subject has been repeated a number of times, and I looked thru many of the older posts concerning this. (Older being the keyword!)

I am wondering what method of cooling people are using. Those of you who are lucky enough to live in a climate where outside growing of highlanders is easy, need not respond. I am interested in those people using artificial cooling methods, and how they like their system.

I am not looking for "ideas" right now, of what "might" work or what would be a "cool" method to try... I simply want to hear from people running highland setups NOW, and what you like about it and what you don't!

I have heard about people running AC cooling, but I wonder how low of temps you can get out of an AC unit? Below 50 degrees? Also, is condensation a problem? Water running off of copper tubes possibly becomes polluted I am assuming... from the copper?

And for those using a modified Refrigerator/freezer... do you have any problems from running it for long periods of time? (An AC unit is built to run long periods of time, but a freezer tends to run for short periods of time and cycle on and off, as the insulation does its work holding out the heat.)

No matter what system you are using, I would love to hear what you like about it, and what you don't. Also, any problems you may have, and how you might improve your system? It is from you current users I want to hear from, and hear your ideas about cooling and humidity, etc. and how it is working out for you.
Well, any comments would be greatly appreciated. Again, I am wanting to hear from those of you who have a system going now. I want to hear about your experience with it.

Thanks in advance to those of you willing to take the time to share a bit of your expertise.

Conditions vary too much around here to make outdoor growing worthwhile, in my opinion. When I previously grew my highlanders in a terrarium, I used evaporative cooling near the top where the heat from the light boxed up (the lights were inside the enclosure) and a combination of an ultrasonic humidifier and passive ducts to cool and moisten dry air from outside the tank. The house is just about cool enough to grow Neps on it's own, but I had them all in the same room as my computer, which stays warmer at night than the rest. (And I didn't know I could take them out of the terrarium at the time.) The passive airflow was great - you just need one outlet where the air is turbulent, and an inlet where the air is still or denser. It's not that dramatic but I noticed a difference in performance afterwards. Not sure whether it was the lower maximum temperature or the lower general nighttime average, but it was certainly an improvement over having my plants boxed into an eight cubic foot space with two Fluorex lamps and no air circulation.
Of course, mine is a best-case scenario, and not probably one you want to rely on heavily for your end product. But passive airflow is always free after you design it into the rig. I think it could be worthwhile as a failsafe feature.
In Northern California, nighttime temperatures are almost always in the favorable range for highland and ultra-highland Nepenthes. Mine remain outside on a deck.

Like many others here, I have neither the time or inclination to establish a cooled highland terrarium -- though I do have a few designs in mind . . .
I'm in Mississippi, and I grow mine as house plants. This is the highlands that I have -
N. Densiflora
N. Diatas
N. Eymae
N. Izumiae
N. Petiolata
N. Ramispina
N. Sibuyanensis
N. Truncata (King of Spades x Queen of Hearts)
N. Muluensis x Lowii
N. Spectabilis x talangensis
N. Sibuyanensis x Ventricosa
N. Ventricosa
N. Sanguinea

I keep my thermostat on 70 during the summer and 65 at night. I like it cool. :) During the winter I try not to run the heat - I run it as little as possible - and it stays around 65 in here. I realize that most people probably keep their houses hotter than this, but I can't stand being hot.

Anyway, I have them on shelves with grow lights. That's it! Nothing else. They are all doing great.

I have my lowlands in a 4-tier grow chamber which makes it about 10 degrees hotter and more humid than my room temps, and they are doing great as well. I put the lowlands outside during the summer, but so far I haven't loved my highlands outside during the winters because it is so variable here. It will get into the teens occasionally, but it will do that and then 2 days later be back in the 70s.
In Northern California, nighttime temperatures are almost always in the favorable range for highland and ultra-highland Nepenthes. Mine remain outside on a deck.

Like many others here, I have neither the time or inclination to establish a cooled highland terrarium -- though I do have a few designs in mind . . .

Hiya BigBella-

May I ask, what happens during the summer?

And for someone like me who lives in the NW with a USDA hardness of 8b, would I be able to keep highliands and even a N. villosa outdoors (probably not the villso during the summers) year long (just bringing them indoors when it snows)????


D'OH, sorry Paul, didn't mean to hijack your topic.

BIGBELLA, if you could reply in a PM that'd be cool . . . thanks
In Northern California, nighttime temperatures are almost always in the favorable range for highland and ultra-highland Nepenthes. Mine remain outside on a deck.

What are your average lows in the winter? I'm in SJ, and it can occasionally get into the 30's. D'you think I can move some highlanders outside?

Entwadumela, the temperatures usually cool down each day in the summer. During a heat wave it may only cool to the 80's, but it rarely lasts longer than a week.
What are your average lows in the winter? I'm in SJ, and it can occasionally get into the 30's. D'you think I can move some highlanders outside?

It generally falls into the high thirties, low forties -- perfect for highland Nepenthes and Heliamphora . . .
Generally my summer temperatures here are perfect for highland/ultrahighland Nepenthes....
Days averaging in the 80s and nights in the low 40s to low 50s.
There are a couple days in the year where it hits over 100F outside.....my plants did not suffer from it during this last year, in my greenhouse none the less.....i just sprayed the inside and outside of the greenhouse down with our hose and ran a fan inside for evaporative cooling....
Gotta love having soft tap water, soft enough to water these plants too...havent had an issue yet **knocks on wood**
I am not currently growing highland Neps but will begin collecting some old favorite HL plants again in spring. I will be utilizing the same method I did before which is pulling cool air from the window (or from a window air conditioner if it's hot at night in summer) through a duct where the output of an ultrasonic humidifier from the pharmacy intersects the incoming air in the duct, and saturates it. This blows a foggy wind into the growing chamber - it's fun to watch the clouds swirl around the plants too! With this setup the plants are receiving fresh cool moist air day and night, I leave the fan and fogger running 24/7/365. The humidifier is attached to a humidistat which shuts off the humidifier when the chamber reaches 80% or so, just before the plants get wet as leaving it run continually leads to fungus, leaves discoloring & spotting. The fan is always running though. Air air air!

Here is a pic which sort of shows what I'm talking about:

Currently there is no humidifier attached as 75% of the plants on the 3 shelf unit are succulents who enjoy much the same temperatures as HL Neps just not the humidity. The other plants are various carnivores in covered tubs.

The vent is powered by a 65 CFM PC fan, mounted to a duct collar (the flat metal piece) & duct starter (a round tube which joins the collar to the actual duct). the air is blown through 4" diameter flexible aluminum dryer vent hose. At each black taped junction there is a "T" which allows some of the incoming air out onto that shelf. Top shelf gets the most air flow and is the coolest during the lights on hours. This can be altered by putting adjustable grilles on the vent outlet and playing with the settings allowing more or less airflow on each shelf. All shelves are currently 54*F tonight but the window is not open very much, about 1/2" and it's 42*F outside. I could make it colder by opening the window more. In hard winter I close the window completely and the fan simply pulls the air from the surface of the window which is cold enough to drop the grow chamber all the way to 40*F.

I think most people get OUTSIDE night temps at least cool enough for highlanders, many places can get too cold or dry to allow them to be fully outside. However, if they rig up something like this that brings in some of that cool night air, humidifies it and delivers it into their growing space they ought to have really no problems at all getting the correct temps & humidity.

When I rebuild this shelf specifically for highlanders I'll take pics, make a new topic and show a bit more details but that's really the gist of my method, bring the outdoors indoors! I live in a condo on the second floor, my house is always 75*F+ but I can drop the temps down for the plants simple as pie with this rig. If there were a way to make this setup more aesthetically pleasing it would be great. Ideally I'd love one that ran all 12 lamps, the fan and humidifier system all with one power cord! :D

But as long as it does it's job, which it does, I'm a happy guy. I got a new PC fan for the duct which goes up all the way up to 217 CFM ( I wanna see about running with high winds in the summer months) but I have to find a power supply that can run it first! 12V 3.5A ! lol
  • #10
swords: I ran tubing like that into a smaller indoor terrarium I had built, had the tubing hooked up to a window AC unit, i would get nighttime temps down to 50 with it, however.... you lose your humidity level... i had worked up some creative ways around it..

just thought i'd throw that in there
  • #11
I hook the duct up to the front of an AC at night from about mid-june -sept to get the night time temps.

If you'll notice I mentioned that I did not have an ultrasonic humidifier and humidistat hooked up in the picture but do use the two when I am growing Neps so that you get cool air & fog (fog=humdiity). No loss of humidity. Infact you'll have too much humidity unless you set up a humidistat to turn it on and off. :)
  • #12
I built an elaborate tank using a minifridge and a waterfall that circulates through the minifridge. At best it only lowers the tbs about 8 degrees F.

Move to San Francisco... seriously.
  • #13
I built an elaborate tank using a minifridge and a waterfall that circulates through the minifridge. At best it only lowers the tbs about 8 degrees F.

Move to San Francisco... seriously.

which is why i will use a decent sized freezer, antifreeze and copper tubing :D i get a 15-20 degree drop now without outside help....hoping to drop it another 10 degrees.....that will put me in the mid to low 50's.....
  • #14
I've got a 5' x 5' indoor greenhouse. I have that inside a spare bedroom. It can get warm inside the greenhouse with the flourescents on, so I have to cool it somehow. In the winter, I keep the room cool by opening the window. Lately it drops in the low 50's upper 40's at night, 70's in the day. These are temps inside the enclosed greenhouse, the room itself is cooler. In the summer, I have to use a portable A/C. This keeps the day temps to about 78F in the summer, 61F at night. If I wasn't able to cool the room itself, it would definitely complicate things greatly.
  • #15
Thank you!

To those of you who actually read my post and understood my request, :scratch:
thank you VERY much for your input.
(Especially Joe & Swords, and also cmm899, Jefforever & rattler)
You have given me some "food for thought".
I know many people who don't want to share their "secret ideas" as it puts them ahead :slap:
of those who are trying hard to create an ideal environment for their plants.
And so those of you who have contributed, I do appreciate your
input. :beer:

It is easy to grow great highland plants when one has the environment naturally,
but I do admire and respect those people who have actually created the ideal environment
on their own. That is where the real work is, and I (and I am sure others) appreciate
your sharing your ideas.
I hope to someday make it possible for anyone to grow highland plants easily,
and it is input like this that will make that a reality.

Like I said, you have indeed given me some things to think about.
Thank you
and Good Growing! :water:

  • #16
my "secret" right now is i live in the frozen north and grow the plants in the basement....have, normally, 3 months out of the year that are to warm for highlanders, where though there is normally a drop in night time temps it isnt guaranteed and we can see 110* highs...however most of our fall winter and spring is way to cold...

also we sleep in the basement and like to sleep in a cool room with lots of covers so even though the furnace is going and the upstairs stays a stable 70* we crack the window at night and the basement is usually bout 60 or so when we wake up in the morning, day temps between the lights and the fact the window is closed my grow room gets to 80 or 85.....but none of this is constant and temps vary a bit depending on alot of factors from day to day....my plan is to make a more stabilized environment using a freezer and a heat sink in a large nearly completely enclosed and insulated grow chamber....

truely my biggest hurdle is between living in a place that naturally low humidity and having central air in the house, trying to keep the humidity up is a constant struggle.....
  • #17
Power Cord Options

Hey Swords,
For power cords, you may look for something like one of these (I saw these on ebay). I assume the size of these is not the best, but it is something you may want to keep an eye out for (or build if you are handy). I have seen a few styles of these, but I didn't pay attention to the size or how many outlets. I thought one I saw at a hardware/junk outlet-store had power outlets every 4 feet, which would have been better for what you need, but that was a few years ago.
I myself have a multi-cord extension... a plug in cord with 5 cords coming out of it. The cords aren't very long however.






I usually either hack up an extension cord and customize it to fit my needs, or just bundle the cords with some extra black-insulated solid core house wiring (I bend the ends over so it isn't sharp), and wrap the wire around the power cords a few times [so it looks like a spring!], and do this in different spots along the power cords. The excess cording I bundle and hide underneath or behind things.

They do sell flexible tubing for this purpose, which has a cut all the way down it to make putting the cords in and having single cords run out of the tube where needed, however these tubes are expensive and don't work well with a lot of cords. They are mostly for a few small cords behind a TV or stereo.

Thanks again for your input on the cooling situation. I do have a few things I am using currently, however it all has problems and needs improving. Every bit of advice seems to trigger new ideas and reveals problems others are having, which in time will lead to new solutions!

Take care & Keep on Growin'.
  • #18
Those are OK but I mean, just one plug coming out of a junction box on the side of the chamber -like everything wired to a small circuit breaker to replace this cord hell:


There is a power strip with 6 more cords you can't even see from this angle! :D

If anything I described isn't clear just ask, I don't get off feeling superior by hiding anything. My setup essentially cools like a greenhouse does by pushing humidified outside air into the growing area but the growing area is indoors and so uses fluorescents instead of sunlight. Keeping day temps cool (below 80*F was best for my old HL Neps and I go for the same for my succulents) is just as important as cool nights. If the air is continually moving and fresh it's hard to wind up with too much heat even in "daylight".

The fact people want a completely sealed system worries me a bit because I think the fresh air hardens plants. Despite the high RH% humidity the leaves on my plants were not not soft and supple like plants grown in a traditional closed terrarium but firm and compact. The air flow also helps stave off excess moisture. I'm 30 mi. outside of Minneapolis, MN so your temps in IL should be quite similar maybe just not the drastic lows we get sometimes. In summer heat just hang the an over the output of a window air conditioner instead of in the window and you're all setup for summer, by making one move. The first summer I had them I put my AC on a timer to just come on at night but leaving it run 24/7 in summer was better since the high day temps wipe out older pitchers, if you retain cool temps some HL pitchers will last up to a year or more.
  • #19
I use a chiller and a cpu radiator. I can get to 12C at night, and probably lower but I haven't tried since that's pretty low already. I have a circuit that toggles the cpu fan in the day so that the temps hover around 23-24C. Without the cooling, the tank gets to 30C in the day, and room temp at night. I plan to expand the system with another radiator and another fishtank, which is just a simple process of connecting it with the chilled water tube. The downside of the whole thing is the price, chillers can get pretty expensive.

I had some bad experiences with mini fridges. The condensation dripped everywhere, the cooling was very ineffective, and I don't think the fridge would last too long since it wasn't made to run like that.

Remember it is important that your cooling system doesn't fail. My plants would be toasted if my chiller blew a fuse (which it did once, luckily i caught it early). After my exams, I will add a bunch of relays that shuts down the lights and sounds an alarm in case the chiller stops working.


The chiller and a bucket to catch condensation

Control unit (not too involved with cooling)

EDIT: after reading the above post, I'll add that I made my system completely sealed since I didn't want to lose any humidity or cool air to my room. Just a different approach :D
  • #20
Yup I believe in the winds! lol

Love the whole digital switchboard thing! Like a mad science experiment! :D

Do you have an internal circulation fan in your grow space just to stir it up at least?