Wonderful thread! I think I'll try this project sometime this winter.
Wonderful thread! I think I'll try this project sometime this winter.
Thanks! Looking forward to hearing about what you come up with. I'm currently gathering supplies to expand this rack to use all shelves on the unit... basically redoing the whole exterior. I'll be sure to update as I go along.
On the topic of supplies - does anyone know of a grow tent that will fit snugly around my 48x18x74" rack? That might be a less work-intensive and low maintenance option.
Alright - so I was bored at work today so I drew out a little plan for how I'm going to structure my grow rack once I redo it. Take a look at the attachment and see if any of this is totally out of whack.
I'm thinking I'm going to draw cool air into the bottom right of the rack and exhaust it out of the top left. Cheap heat sinks will aid in heat dissipation.
The whole idea of this setup is that it will be much cooler on the bottom shelf than the top shelf just based on the fact that warmth rises. Hopefully humidity will be consistent across the whole vertical space, as will the night time temperature once all the lights are off. But during the day I'm hoping to achieve temps no higher than the low 80s on the bottom shelf and mid-high 80s on the top during most of the year except for July & August... during that time my apartment gets so freaking hot that it's all I can do to keep the temps below 90.
The drawing should be more or less to scale, so the top and bottom shelves will be a good deal higher than the middle shelf to allow for Neps to vine and stretch before I have to chop them up and give their limbs to you lovely folks (yes, I do intend to make good on this promise just as soon as my Neps let me...). The middle shelf will be for my lower growing plants like dews that are, for the most part, more heat tolerant since they'll be closer to the lights.
Also, I'm revisiting the idea of creative cooling. I just picked up a nifty wireless thermo/hygro from Lowes for 60% off (it was only $9 on sale). Yesterday I was reading max temps of 85 degrees and change, min temps of 73 degrees overnight, and RH between 55% without the humidifier running and 68% with it on half power--and of course the RH spikes to 80-90% overnight without the lights on to burn all the moisture out of the air. Pretty happy with this since the rack only got about 2-3 degrees hotter than ambient temperature (on my Nep shelf at least), which is real nice considering that yesterday was pretty toasty here in NYC. But if the days are hotter--and there are plenty of hotter days on the horizon next July & August--temperatures could easily spike into the high 90s. SO what I'm thinking is to take a decent-sized tupperware container, cut two holes in it (air intake and exhaust), stick a DC fan on one end to blow through it, load the container up with gel ice packs, and throw it in my rack overnight to create a good temperature drop. That would let me move into other species like some HL Neps and maybe even Helis. High maintenance, yes, but simple and cheap. Anyone tried this before? My family is from the swamps of Louisiana and they call this device the Cajun AC, although local implementations of the concept usually involve a brick of ice in a crock pot sitting in front of a fan.
Lots to think about... thoughts, comments, suggestions, death threats... all welcome!
EDIT: Hmm, forgot I bought a couple of cheap Cattleya mutts at Lowes yesterday too, to make good on my last botched attempt to grow them. I have them in my rack now, planted in proper orchid mix (not pure sphagnum packed way too tight and kept way too wet for a Catt as was unfortunately the case last time). I'm sure these plants would be happy on ONE of these shelves...
Here it is - redone yet again!
I've expanded it out to use all four shelves. Currently only three are in use. I used some cheap shower curtains and mylar blankets to make a little "tent" that I held up with velcro and binder clips.
Temps... a little higher than I'd like, but this is before I've done anything to pipe air in from outside the rack, and I took this reading only seconds after turning the humidifier on. The "In" temp is the temp on the top shelf with my dews/pings. The "out" temp is reading from a sensor placed on the Nep shelf below. This is just the temperature of the recirculated air. Not too bad, I guess. But I fear I'll never be able to grow highlanders!
The newest guest in my rack. Don't worry, I bought it this way; I can't claim credit for growing it to this point! Although I hope I can KEEP it growing.....
S. oreo seedlings. They haven't grown in a while; some have withered, but others look alright. Time to re-pot?
Lowes Cattleya mutts - they've lived longer than two weeks for me now, which is more than I can say for my last attempt...
Recently repotted S. purpurea venosa already filling out its 6" pot. This thing is indestructible; I shouldn't be able to grow sarrs on a rack without dormancy!!
Just a few updates:
Got my new SPT SU-2000 humidifier today. The piping sucks... I'm gonna have to get something thicker and more flexible.
Also hooked up a new drip irrigation system for my Neps
...And also hooked up by new Hygrotherm
Drip system in action in my N. mirabilis pot
Some new dews: clockwise from the far left, D. nidiformis, D. capensis "white," D. filiformis "Florida All Red," S. purp venosa, D. intermedia "Mt. Roraima," D. prolifera, D. adelae
D. nitidula x pulchella flowering
P. 'Sethos' (front) and P. 'Titan' (back) looking much happier after a recent repot
The whole shelf
Looking good, dude!
Indeed. Most indeededly. Phillip J. Frye
Do you use your hygrotherm to switch off/on any other devices like fans/lights/humidifier? It looks pretty neat.
Sorry if I missed this earlier in the thread but how much did you pay for your heatsinks and where did you find them?
@gill_za - one reason I got rid of it was that it was a pain to roll it up every time I wanted to get at my plants... LOL! But yes, it wasn't quite as effective at keeping humidity in as I had hoped. The seal just wasn't awesome. Maybe I could have augmented it with magnets or something. Also, as I wanted to expand out onto four shelves, it would have been even more difficult to hang a 6' tall, thick sheet of PVC down the whole front of the rack. That stuff is heavy!
@Peat - I use my hygrotherm on two devices. First of all I have a PC fan running constantly, day and night, and another one that goes on and off with my light timer (one on the upper shelf, one on the middle shelf). My hygrotherm controls two humidifiers (a SPT SU-2000 and one of those lame portable ones that accepts a drinking water bottle) and also two air intake fans. These fans are currently mounted in an open window to draw cold air in from outside. When the temps get above 75, the fans kick in. In the summer that won't help much... with outside temps frequently above 80 degrees, my plants will be pissed off no matter where the air gets drawn from. But in the fall/winter/spring, it's great for achieving a significant temperature drop - right now I'm pulling mid-70s during the day and mid-50s at night!
The heatsinks were purchased from www.mcmaster.com - this is the heatsink I got, although at the time I bought them I actually worked for that company so I got a reeeeal nice discount on all my grow rack supplies (should have bought those discounted T5 fixtures when I had the chance!!! ). If $7.00 or so a pop is too rich, try searching Amazon for heatsinks. You'll get a bunch of results for CPU heatsinks, but also a few for these general-purpose equipment cooling heatsinks, which can get pretty cheap if you hunt around.[COLOR="green"]
EDIT: double post, sorry guys