How hot is too hot? (Plant Rack Question)
So I have a plant rack set up in my apartment. It has the standard 4' wide T5/8s, wireframe shelf, with the plants being about 4-8" away from the lights. (Smallest pots are 8" away, my neps gets closer to 2-4ish.
All sides of the rack including top and bottom are covered in tinfoil to maximize reflection, with the front having a space blanket (Mylar sheet) instead (so it's easier to lift to get into them). There are no fans, and the thermostat is steady at about 90F-95F.
Lights are on from 7 AM till 11 PM (16 hours) using a timer, but I can adjust this at will. I've been considering moving them outside for the summer, as it's nice out and I do have a small amount of space at my apartment complex.
Everything's dying. Some slower than others, but it appears that everything in the rack is undergoing a slow death, or at the very least "isn't happy"(tm).
I've checked the water, it's 75-80ppm, so in another 3 months or so I'll want to replace my filter, but that's probably not it. I haven't updated my lights in a very long while, so it might just be lights going bad after a time, but I would be surprised if it was that, too.
* Neps turning yellow and brown in spots and lines, sending out deformed pitchers. They've also got the occasional "red dot" patch on some leaves, but this has stopped as of late.
* Sundews dying back, but sending up constant new growth. My D. Giant is sending out flower stalks nonstop this month, 3 or 4 at a time (I fed him last month). No dew on most, but the pygmies and filiformis are pretty happy.
* Biggest Ping. Gigantea wilting and turning yellow on the edges, but sending out new growth. Smaller pings doing fine with one exception (he dun exploded).
* Dunecraft container with LFS in it had the LFS turn yellow as well -- this was kinda the last straw.
The first sign was dieback in the big drainless rectangular pot I had, making me assume that it was mineral buildup or bad soil or something -- that container is basically what scraps I had left of soils, mixed together and then a hodgepodge of plants thrown in. But only the sundews died back (although the random pitcher plant someone gifted me locally has never done very well), and literally everything that did has sent up massive amounts of new growth and/or came back from roots. But then the problems spread to my cape sundew (mass dieback, new growth stunted and dewless), and my biggest pings.
I'm assuming it's heat given that the Pygmies are doing fine still, and they like it a bit hot. But it could be decaying soil, bad lights, bad water, or even tiny bugs -- I noticed my pygmies and pings had a small dusting a little itty bitty bugs, as well as the bottom of the rack, but that appears to have stopped.
What is an appropriate temperature to aim for? I took off the "lid" of the rack, it lets a little light out but also, in theory, heat. I could take off a side and place a fan up to get some air circulation in. I have no problems with mold although some alge continues to grow in one pot and the sundew's deep saucer.
Edit: Addendum: I just checked the temperatures, after an hour of being off with the "lid" having been removed, its down to 80 in there.
tl;dr: 90-95F for a grow rack. Too hot?
Last edited by mcantrell; 08-08-2011 at 10:58 PM.
If you are growing Lowland heat loving Nepenthes such as N. bicalcarata, N. ampullaria, N. mirabilis and so on 90-95*F (with correspondingly high humidity) would be fine but other Nepenthes don't appreciate such high temps. My Lowland tanks tend to be between 80-90*F during Lights on and 70-75*F with lights off and 90-100% RH.
Just a standard ventricosa/ventrata... nothing special. I'm most concerned at the fact that this seems to be spreading amongst the other plants.
I suppose it could be me not watering things often enough, but the saucers never get dry. I did move the biggest ping into a ceramic planter that's JUUUUST big enough for it's 4" plastic pot to fit in. Doesn't explain the sundews all wilting.
Unfortunately I discovered just now that at night, the sprinklers (about 280 ppm water) hits where I was going to keep the plants outside, so that's out.
I'm leaning towards a cheapo fan for the time being, and maybe keeping as many plants outside as I can, to improve airflow. With all the extra plants I have now (that Gigantea has split a ton of times, for example) the rack was fairly full. Maybe something I can clip on to one of the 4 bars of the rack and just point at the ground, the air bouncing off the "floor" of the rack should stir things up and send it out the top.
I hate bugs. Carnivorous plants get me.
Late last summer I had temps creep into the 90s in my terrarium and the dews did not like it one bit. Which species are you growing? The pygmies may still be fine so long as you keep them watered well but if they dry out at all then you risk them going dormant.
My ventricosa acted pretty much the same as well.
I have a mostly up to date list in my signature, but off the top of my head:
Originally Posted by jpappy789
Binata (lots of dieback on this guy)
Cape Sundews (this is most worrying, as the one that's doing all the dieback is my first CP from years and years ago.)
Dichotoma Giant (back to it's roots in the big pot, just fine in it's 3" square pot except it's stuck in "send up flower stalk" mode)
M. Extrema (died back to it's roots)
Filiformis "Florida All Red" seems to actually be doing fairly well.
As for the pygmy, it's... pXm I think? I forget the exact latin. Incredibly common variant, I believe?
Temperatures in the rack are still 80, 6 hours later. That seems to be the balance point right now for the room.
I'll try and get some pictures shortly.
I hate bugs. Carnivorous plants get me.
The capes are a big problem with heat, they generally like it below 80F or so. That is one that I specifically remember hating the late summer weather. I believe my binata was the same way.
The filiformis probably can tolerate it well seeing as it is from the southern US (I think).
It seems like all of these would do better with lower temperatures, especially the Nep. ventricosa at least is a highlander and I believe alata is too. You say the "thermostat" is set to 90-95. Do you mean a thermometer is reading 90-95? Or are you actively regulating the temperature to be 90-95? I'm guessing you meant to say thermometer.
Given how close the lights are to the plants, the foil covering the front and the sides may be trapping in too much heat. I would try simply not using a front sheet at all. The extra air movement will help dramatically, especially if the room is cool. You won't lose as much light as you think. Seedjar made a similar suggestion to me when I was building my rack and it made all the difference.
Also, maybe I'm overly cautious, but the plants sound awful close to the lights if you're talking about t5's. I think mass had a thread recently about increasing the distance between his t5's and neps and they were a foot or two away to start with. Most of my neps and air plants are about 12" from the t5's and coloring up well.
Yes, thermometer, not stat, sorry. The rack is right in front of the room's thermostat, which is why it's always in the back of my minds when I go in there, heh.
Not sure if they're T8s or T5s. I can adjust the rack (it's a $80 Costco rack, very common) but that would be a lot of work...
They're exactly big enough to fit in the mounts without being too "fat" -- about the same diameter as a quarter, just about.
I went ahead and took off the front foil (the space blanket), although I probably should have moved it out of the way first. Ah well, not like it's destroyed.
Edit: Left the front film off all day, it's a little colder in there but not much -- 88ish instead of 90ish. Will get a small fan tomorrow.
"Not sure if they're T8s or T5s"
measure bulb diameter
T12 = 12/8ths = 1.5"
T8 = 8/8ths = 1.0"
T5 = 5/8ths = 0.625"