Im currently running my plants under a 4 tube 4 foot fluorescent. Now im wondering when the best time to switch to my 1k hood will be, it will be run at 600w, then 750, then 1000 as needed. -How old/big should the plants be to turn on the big light? -Switch when the nutes are started? This is 11 days from germination:
If there far enough away from the light it doesn't really matter when they go under HID lights but it never hurts to leave them under cfl or floros a while to get them strong
Will take that into consideration. Im having trouble keeping the plants cool under the flouro, cant imagine under the HID. The plants register mid 80" even withj the fluorescent 13" away. Only a 4ft 4 tube.
You need vastly more air flow if the fluro's are so hot they have to be 13" away. What's your ventilation like ? 210 watt perpetual box https://forum.grasscity.com/index.php?/topic/1394922-210-watt-3.5-sq-ft-Northern-Lights-and-White-Widow:
Well that needs to be fixed before you can run your HID anyway. Your fluorescents needs to be within 4" of the plants. What's causing all the heat to build up? Do you have your exhaust fan on full speed? If you fix your heating/ventilation problem, your fluorescents will be good for at least 3 weeks of growth, even more if growth is slow
Anytime you want really, 200w of T-5 lighting is good for at least another 2-3 weeks if not more. I understand that you're battling high temps so do what you've got to do. You'll get faster growth rates with higher watts, but having a balanced environment is paramount. That being said there's nothing wrong with running 1kw from day one, it's not going to hurt them as long as your environment is balanced. I do it all the time with autoflowers, these babies are just sprouting.
yes its on full, and i also have a fan on oscillating in the tent, which is why im stumped. This fluorescent seems to put out a lot of heat for some reason. Ive been raising it more and more to see when the temps of the plants are good, and 17 inches is where all the plants under it register at80 when the temp is taken, and the overall temp of the garden is 77-80.0 --I think im going to have to add CO2, cheaply though, already over budget. --The exhaust fan is venting into the attic which has soffets, once i fully install the exhaust will run all the way into a soffet, wont just be collecting in the attic. -----------I literally don't know what else to do to cool the temp down at the plant level besides raising the light. The ambient temps are fine for now, just the plants themselves are too high with the high output fluorescent. Pics:
Oh right, you have a proper set up. That isn't what I was expecting lol. Is the tent sealed up fully? Any places where air can get in at the top will cause the ventilation system to bypass the heat given off the light. I like to keep the bottom of my doors unzipped to allow more air inside. What brand is your exhaust fan? How long is your ducting? It's best to have it as short and bend free as possible Btw, anywhere between 68-86 is usually fine
That's actually what ive been doing the past two days, is have the bottoms of the doors unzipped, seemed to help by letting cooler air in. I have to double check but i think i have everything sealed in the top. --There are two bends in the ducting, only one that's about 90 degrees, and im using the full length of the ducting right now which is 20 feet just to get into my attic and away from being over the room, in 2 days i will be adding a fan at the end of that ducting and some more ducting to push it completely out of the attic(intake>fan>duct>fan>duct>out) --Would you recommend putting a duct on the intake of the exhaust fan so its in the middle of the tent or aiming it just above the light? I normally wouldn't consider those things, but im at a loss right now. I have to keep the light at 13" , and have a fan blowing at the lightbulbs from by the plants to keep their temps down to 80-83, any closer and they fuckin roast, Im thinking those high temps they were experiencing, along with some overwatering are why they are so small for being two weeks old. --Just to clarify, the ambient temp in the tent is 80 max, its the actual temp of the canopy im talking about when im saying 80-83(used to be 90 when the light was closer)
It seems like you're trying to reduce the effect if heat at the canopy level, not the ambient temperature. There is a limit to how effectively you can do this. A glowing ember is still hot to the touch even in Antarctica! But you can have a more localised cooling effect by having a stream of air passing directly over the canopy. Either jig around the intake/outlet so you're guaranteed to draw air through the plants from across the room, or have a separate fan blow air across your plants. The easiest way is to raise the lights an inch or two, which as you've discovered can be very effective.
Like i said the ambient temperature is fine, now my problem is just reducing the canopy heat. From what ive been reading, everyone says you can put fluorescents very close up to 4 inches to the plants, but i don't see how without burning your plants. I used to have mine at 8" and they were very very hot. Ive also read anywhere from 6-24" is fine. Mine is a high output, and it puts out a lot of heat, im thinking if exchanging the light because of this. I already have a fan oscillating across the plants, anfd another one blowing at the light to remove heat at the canopy level. -What do you mean by "jig"? I think i understand but i want to be clear.
I would say your problem is that ducting. For two reasons. The first being it's so long that hardly any air is being moved. And the second, because it's so long the air has probably gone cold by the time it has gotten to the end by radiating the heat through the duct itself. For a few hours unhook the ducting so the fan is sucking air out the tent and blowing it openly in the room. Just to see what difference it makes. I bet it will be cooler What is the temperature outside of the tent?
I meant something like arrangement or setup or to position the equipment, that'll all. How close you can get your lights is (usually) all about heat which is all about power. CFLs and fluorescents are usually lower power than HID, but 100w light is still pretty much a 100w electric heater whatever kind of bulb it is. When plants are bigger they can handle more stress. Small plants will cook at 4 inches from the lights, but 2 weeks later they might cope fine. They'll grow better and healthier with less light and less heat stress, than more light with more heat stress. Try to avoid pushing the limits and trying to optimise things like the lights, until you've had a successful grow. They'd grow and bud fine if you kept the lights at 24 inches, I'm not suggesting you go that far but it wouldn't be the stupidest thing to do. Good luck!
Not only should you be able to keep the light within 4" inches, you should keep them within 4". Obviously you can't at the moment, but a fluorescent light over 6" is going to be weak as hell. The intensity just isn't there. Is your HID ballast dimmable? I see that you have an air cooled set up? If set on low wattage it may be cooler. But if that ducting is also 20' long you may have the same trouble If you can't shorten the ducting then a bigger fan with wider ducting may be necessary. You may also need to use insulated acoustic ducting to prevent the heat radiating back in to the room before it gets to the attic
yes it is dimmable. And I think I'll switch over soon. -to solve the problem of the long ducting I was going to add another fan halfway to the out point/exit of the air. I thought that would be sufficient.
What's the lowest it will dim down to? What wattage is your fluorescent fixture? Another fan will help, but to be brutally honest it sounds like your ventilation is literally accomplishing nothing. Are you able to shorten the duct? What about moving the tent directly under where the duct goes up through the ceiling?
No, its basically where it has to stay. Dimmable to 600w. The ambient temps have been at 78 the past two days. Like I said, just the light gets warm. I'm assuming if the exhaust wasn't doing anything the room would immediately heat up when the light came on and wouldn't be creating the negative pressure I have in the room, correct?
It depends on the wattage of the florescent. I mean if it's low wattage and its still overheating then there's no way you could run your HID at 600watts