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...
. Hope you get some good growth soon and thanks for sharing!
). 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.