I'm on my first grow. My veg room is a closet which is 4'x3'x9'. I am running a 4 inch 190 cfm fan with equivalent scrubber, a 900w full spectrum led, (2) 6" oscillating fans and passive intake. The fan vents to the attic. The intake is pulling from a room that is cooled by central A/C with ambient temp around 76F. The temp in the veg room stays around 78-79F with 50% humidity. I bought a new tent specifically for flowering. It is 3'x3'x6'. It has a 6 inch 440 CFM fan with equivalent scrubber, 600w HPS with a cooltube, a 65 cfm intake fan, and (2) 6" oscillating fans. The temp won't drop below 84F with 42% humidity. The room the tent is located in is also cooled by the central A/C in the house and the outtake vents to the attic. Before putting my girls in the tent, I wanted to make sure there were no light leaks and whatnot. After about an hour running the HPS at 100%, the temp was 88-89F. I turned the ballast down to 75% and the temp dropped to 85F. I tried a 600w MH in the veg room without a cooltube and struggled with heat issues so I went back to LED. I assumed the reason for the issue was due to not having a high enough cfm fan to push the heat out, no cooltube or intake fan. So when I bought the tent I purchased the bigger fan, intake and cooltube. I don't want my girls to hermie because of heat. Both of them have been in veg now for 6 weeks to recover for being stunted early on due to bad lighting. One is still half the size of the other. I'd hate to have them hermie or die now because I couldn't manage the heat. Short of buying another LED, what other steps can I take to get the heat down? I appreciate any suggestions you may have.
How is your light hooked up to the vents? If its hooked up to a cool tube or sealed reflector you could put ducting straight to the light and have it vented straight back out the other side of the tent
I've attached some pictures so you can see how it is setup inside the tent. The airflow pulls into the scrubber through the cooltube and out of the tent. The fan is outside the tent mounted on the wall then vents through a hole in the ceiling into the attic. You can't see it in the pictures but there is a 4 inch inline fan flowing air into the tent on the bottom left near the door. I can tell the air is pulling through the cooltube because the duct hanging down on the left will contract when the fan is on. The fan does have a speed controller attached but I've been keeping it on full.
You probably just need to cool the room it's in. i have a 600 watt hps right now in a 4x4x6.5' box and i need to keep the room around 68-70 to keep the box at 79 with the light at 100%. Really all i can add to the conversation sorry man.
I have a 600w HPS and a 300w LED in a tent of 3'x4'x6' with a 4" fan sucking through a filter and blowing straight out, and a 5" fan cooling the HPS bulb on a sealed separate line. My tent temperature is usually only 2 or 3 degrees over the room temperature. The room is very small, not forcefully vented and I have two tents in the room. From what I see in the photos you have a lot of ducting, is all that needed? Do you have adequate intake vents? What brand is your exhaust fan?
It wont solve all your problems but get that slack out of the line between your tube and filter and try to get it as direct of a route as possible. Always keep duct runs as short and straight as you can. Also,if that 4" duct fan is your only intake then it is going to limit the flow of your exhaust. As a general rule you want your intake area to be around 2x larger than your exhaust. So if you have a 6" exhaust you want the equivelant area of a 12" intake.
Mine actually looks a lot like his, when i read up they all said you can have bends in your intake but like to cycle my box's air once pre minute i need 100 cfm, With bent ducting i need 200 cfm to cycle the same amount of air so i bought a 440 cfm fan for my 96 cf box. it's still a little hot but i can control it with room temps and i needed the ducting to be able to lower my light to the young plants. He probably read the same stuff i did, i personally couldn't figure out a way to get rid of the ducting and still be able to lower the light. i'm guessing my box holds more heat in though because it's wood.
How low do you really need the light to be? Small plants require less light so having it at a larger distance usually works out just fine. As they grow and get bigger they can handle more intense light and can be closer. My light is adjustable from about 4' off the floor to 6' off the floor. If I had the hood closer than 4' then I'd have to lower the wattage and the light would be concentrated in the middle and the border wouldn't get much at all. Ducting is coiled and can be stretched out, it can also be compacted to make a shorter length. Maybe trying to compact it and tape it up might make a difference. Bends and long ducts really cause a lot of drag
I dropped my a/c to about 65 for about 4 hours to see what type of difference it made and it was about a degree or 2 drop but since its central air it had to cool the whole house to that temp so I'll have to find another solution otherwise I'm going to give the power company a ton of money and probably alert them to what I'm doing. My duct goes down about 4" off the floor on the left. On the right it is compressed but there is another 4' outside the tent to the fan. So I'll reduce some of the length on both sides. I like your setup, I think i'll try with 2 fans venting out and take the scrubber off the light. The walls of my tent are already sucking in with my current setup which has a 4" inline 65cfm fan and a 4" passive intake. Do you think I may another fan intake as well?
I Your ducting hangs down to 4" off the floor? You are better off adjusting the light to the lowest position that you will use it. Then cut the ducting so it's straight and tight in that position. This is then as short as possible. When you raise the light the ducting will slacken a bit, but you shouldn't have such a big loop in it. If you have 2 fans then I'd definitely go with how mine is set up. It's more efficient and your carbon filter will last much longer. Have the biggest fan on the hood and the smallest fan on the filter, that way you can get away with buying smaller filters too. Have the fan blow through the hood and not suck. Make sure you have plenty of vents open to let cool air in at the bottom. I leave the bottom of my doors unzipped to allow plenty of air through
the way I have my light is like this fully extended And when it's raised the ducting scrunches up so the duct becomes much shorter
Just my opinion here, it seems like you have a lot going on in there man. I'd get those in lines out of the tent. Having more space and less shit in your tent will make your life much easier once your plants start growing up. A clean setup and all the space utilized BLEED GARNET&GOLD -"-》--;->>
I haven't cut the duct yet but I did tie it up with some paracord so that it was even with the light and scrubber and in about 20min the temp dropped 3 degrees to 83F. The humidity has been 32% all day so I just dropped in a humidifier to see if it'll raise the humidity just a bit and drop the temp a little more until I can pick up another 200-300 cfm fan. My girls are anxious to get into flowering... well maybe they aren't but I sure am. Here they are... Looks like the bigger one starting to show a nitrogen deficiency and has an oddly shaped leaf. I've always fed and watered during the light cycle. Is it ok to feed during the lights off or should I wait until morning when the lights are on?
That's awesome that you already had a temperature drop. Yeah you can water in the dark period. If it was in flower then it's usually not such a great idea but as its still vegging it will be fine
Now that's 2 ideas I can check out. I think I have most of the basic stuff for a diy swamp cooler. I just don't know that I can build it so that it doesn't create too much humidity in such a small space and potentially cause mold. I'll have to youtube it . Thanks for the suggestion, I never would have thought of it.
What kind of humidifier are you using? Cool mist? Warm mist? And bro I wouldn't stress over 32% humidity. I battle low humidity all winter. They'll drink more but you'll be fine. Your extraction fan is going to fight whatever humidity you are able to add. Swamp cooler may be exactly what you need. All you can do is try it and see. If you already have the parts. Bucket or 2, a fan not much else is needed.
I have a Vick's cool mist humidifier. Its not very powerful so it only dropped the temp a 2 degrees and the humidity only jumped to up to 38%. I just watched a youtube video on the bucket swamp cooler and it does look like it'll do the trick. Even better I have virtually everything for it. I like the 2 fan thing as Gold Grower mentioned but I do have limited real estate in such a small tent, adding more ducting and an extra fan will take up more space. I think the swamp cooler might be the better solution for this situation. I may redo my veg room with Gold Grower's suggestion so I can try the Metal Halide again. Don't get me wrong I love my LED but I want to see how they compare in yields.
It shouldn't build too much humidity because some of what it does build will be getting sucked out by your exhaust. Once you get to a certain humidity level the atmosphere doesn't suck up as much from the cooler either. I use a window mounted swamp cooler to cool my home and they work great below 90 degrees or so when humidity is extremely low. I usually get about 10 to 15 degress temp drop from my home unit.