Help Please w/ LED Lighting: Veg vs Bloom Switch vs Increase in Temperature

RayRay747 · Dec 11, 2017

Thanks in advance for your feedback and help. I am running into an issue with my “daytime” temperatures in my grow box.

Opening Details:

600W LED Lights on/off: 18/6 | Wall oscillating fan on/off: 18/6 | Wall oscillating fan on/off: 24/0 | 6" Vortex fan (I think I am pulling lol): 19/5 | Cool air humidifier: 19/5

With the lights on and just using the VEG option, I can maintain a steady room temperature (sensor is placed in top corner of room opposite Vortex fan) of 79F degrees and 50-55% RH.

My issue is when I turn on the VEG and BLOOM options simultaneously, the room temperature increases to 85-87F degrees and maintains a 45-50% RH.

The surface temperature and RH with just the VEG option on is around 75F degrees and 45-50% RH. With both the VEG and BLOOM options on, the surface temp is around 80F degrees and 40-45% RH.

With the lights off (“night time”), I can maintain a room temp around 69F-72F and RH increases a bit to around 60-70% RH. I believe the increase in RH is because I do run the cool air humidifier for an hour after lights off, have a tray of water in the room and turn the exhaust off an hour after lights go off. So I am sure this causes the RH to build up in the room when the temp is already dropping the humidifier adds to the increase in RH.

Are the high temps with both VEG and BLOOM options turned on ok? Its perfect IMO when I have just the VEG option on but goes downhill once I turn both switches on. I am thinking its ok to have both on and deal with the high temps during VEG but when it gets to bloom I think it will be an issue. Thoughts?

Grow Box Details:

4’ish x 4’ish x 6.5’cish Grow Box - guts are green board painted with exterior paint, caulked all joints and sprayed foam insulation on all joints, added roxul insulation, sealed it with vapor barrier, then final layer is reflectiv radiant heat barrier. It’s fairly air tight minus the 3 4" intake holes I have (which I think might not be enough considering I have a 6in exhaust)

Box Accessory Details:

6" Vortex fan running full speed on 19/5
VIASPECTRA 600 Watt LED on 18/6
Air humidifier on 19/5 (or until water runs out)
2 oscillating fans (one mounted on wall just above lighting which runs 24/7 and the second one sitting on the ground which runs with lights on 18/6).
Tray of water on ground (increase humidity)
SensorPush thermometer/hygrometer to grab ambient temps/humidity - placed opposite vortex fan in top corner.
Basic thermometer/hygrometer hanging between plants shaded by the lips of the pots.
Three - 4" intake holes (one connected to outside vent to bring in fresh cold air using the negative pressure). It’s dang cold here now so the air is probably fairly cold when it finally hits the box. The intake vent ducting runs about 15 feet from the outside vent entrance to one of the 3 intake holes. I have bug mesh and HEPA filters covering all 3 intake holes, my exhaust exit hole and my fresh air intake hole. I don’t have an intake fan, though I think if I hooked one up to the fresh air intake it this would help bring in a lot more cold air into the box and drop the temps to where I want them to be. Not sure tho.

My thoughts are: 1) Install an intake fan to pull the air more strongly through the ducting from the exterior vent to the intake in the box. 2) Keep lights on only VEG until flowering, but I would still have the issue at that time and would lose the light intensity to assist in the growth period. 3) Cut one or more intake vents (maybe one 6" intake vent or another). 4) Add a swamp cooler

Troubleshooting done: I cut open the ducting in the box to make sure there was nothing obstructing the air flow. Taped it back up now and made sure it was sealed back tight. Now I do have a bug mesh and HEPA filter on the exhaust hole so I do believe this would slow the flow down, but I wonder if that would hinder the flow enough to keep it from getting out of the box through the hole and into the ducting - should I remove the HEPA filter? 2) I calibrated the thermometers/hygrometers to ensure accuracy.

Sorry about the long post but wanted to make sure I covered all I could. Any ideas on what I can do?

Thanks so much...

KrazyG · Dec 11, 2017

Hi your problem may be a simple cure, if I read correctly your temp probes are in the top corner of your box and should be at the plant canopy. GL

RayRay747 · Dec 11, 2017

KrazyG said:
Hi your problem may be a simple cure, if I read correctly your temp probes are in the top corner of your box and should be at the plant canopy. GL

Hey KG - I have my SensorPush up in the corner to read my room temps/ambient temps. Maybe I have that wrong.

I also have another thermometer hanging between the plants around canopy level.

My major issue is that when I have the VEG and BLOOM switches on the temps raise about 5-7F degrees. When just VEG, I think I am almost in the perfect temp range along with RH. I can lower the RH pretty decently by keeping the fan running and removing the humidifier and water trays.

I also feel that maybe the HEPA filter that is inside the ducting flange might be restricting air flow. I was worried about the quality of air leaving the box, but maybe I should just worry about the quality of air coming into the box.

Im stumped.

KrazyG · Dec 11, 2017

RayRay747 said:
I also have another thermometer hanging between the plants around canopy level.

Whats the reading?
Yes remove the HEPA and see if that improves things.
Where are you exhausting to? If it's back into the room this will raise the ambient temperature and have a knock on effect.

RayRay747 · Dec 11, 2017

KrazyG said:
Whats the reading?
Yes remove the HEPA and see if that improves things.
Where are you exhausting to? If it's back into the room this will raise the ambient temperature and have a knock on effect.

The canopy reading is typically about 5F degrees less than the one in the corner. For i.e. when the VEG and BLOOM switches are on, temps rise to around 86-86F degrees. The canopy level temps are around 80-81F degrees. I just worry the room temps are way too high.

And also curious why the Vortex 6" S-line fan is not doing its job in such a small space. I got the bigger fan to make sure I had enough power, but it seems as if its not enough. Yeah Ill have to cut open the ducting again. Thinking it may be best to run new insulated ducting then vs trying to patch it up or would you just patch it up and go from there? Unsure if I will lose suction if the ducting inside the insulation is not fully sealed. Ill probably just take the extra 20mins and redo the ducting to be safe.

I am exhausting into my basement. I have 3 intake vents. 2 (if negative pressure is working correctly) are pulling from the basement and the 3rd is pulling from outside to get fresh air coming in. I just feel that for some reason the fan is not functioning at its full potential.

coreywebster · Dec 11, 2017

KrazyG said:
Hi your problem may be a simple cure, if I read correctly your temp probes are in the top corner of your box and should be at the plant canopy. GL

Actually they shouldn't , they should be above the light line reading air temps, although its not as vital with LED since there is very little radiant heat to distort the readings like with HPS.

coreywebster · Dec 11, 2017

RayRay747 said:
The canopy reading is typically about 5F degrees less than the one in the corner. For i.e. when the VEG and BLOOM switches are on, temps rise to around 86-86F degrees. The canopy level temps are around 80-81F degrees. I just worry the room temps are way too high.

And also curious why the Vortex 6" S-line fan is not doing its job in such a small space. I got the bigger fan to make sure I had enough power, but it seems as if its not enough. Yeah Ill have to cut open the ducting again. Thinking it may be best to run new insulated ducting then vs trying to patch it up or would you just patch it up and go from there? Unsure if I will lose suction if the ducting inside the insulation is not fully sealed. Ill probably just take the extra 20mins and redo the ducting to be safe.

I am exhausting into my basement. I have 3 intake vents. 2 (if negative pressure is working correctly) are pulling from the basement and the 3rd is pulling from outside to get fresh air coming in. I just feel that for some reason the fan is not functioning at its full potential.

A 6" fan should do the job if all is working correctly. My Veg tent is a 600w MH and 5" fan and I have it turned to 1 out of 5 on a speed controller and its fine. Obviously our conditions are different.

The problem could be the 15 feet of passive intake ducting. I'm all for passive intake but 15" of ducting is a lot to overcome.
Also if you have 3 passive intakes it will only pull from the one with least resistance, so if you have a longer distance to outside you will be just drawing air from the basement. Like KrazyG said, your recycling the same air if your venting into basement and drawing the air back in.

The best option is to extract warm air straight to outside. If you cant do that then only use the one intake from outside, either way your not recycling the same air. Plus an intake fan may be needed if you cant shorten that 15ft intake.

This is most certainly a sortable problem your just going to have to tweak your set up.

RayRay747 · Dec 11, 2017

coreywebster said:
Actually they shouldn't , they should be above the light line reading air temps, although its not as vital with LED since there is very little radiant heat to distort the readings like with HPS.

Hey Corey - thanks for the input. I do have two thermometers in the box - the SensorPush is in the corner right above the hanging os fan and the other is hanging at canopy level.

Just checked my SensorPush app and temps is steady at 80. But that is just with VEG light on. The issue is when I turn on BLOOM and VEG the temps jump to 85-87F

RayRay747 · Dec 11, 2017

coreywebster said:
A 6" fan should do the job if all is working correctly. My Veg tent is a 600w MH and 5" fan and I have it turned to 1 out of 5 on a speed controller and its fine. Obviously our conditions are different.

The problem could be the 15 feet of passive intake ducting. I'm all for passive intake but 15" of ducting is a lot to overcome.
Also if you have 3 passive intakes it will only pull from the one with least resistance, so if you have a longer distance to outside you will be just drawing air from the basement. Like KrazyG said, your recycling the same air if your venting into basement and drawing the air back in.

The best option is to extract warm air straight to outside. If you cant do that then only use the one intake from outside, either way your not recycling the same air. Plus an intake fan may be needed if you cant shorten that 15ft intake.

This is most certainly a sortable problem your just going to have to tweak your set up.

Hey - i actually did the intake ducting about 3-4 days ago because the temps increased. I felt maybe if i drew in cold air from the outside it would help lower the temps. But that didnt work. So my other thought was something was obstructing the ducting before the air made it through the exhaust hole and out into the basement. I dont feel much of the air coming out of the end of exhaust which only runs about 4 feet and vents right out of the top. The basement stays around 60F almost all year long so I still dont get why it wont cool off. The only time when the temps are optimal are when I only have the VEG switch on. When I do both VEG and BLOOM all of the idealness goes out the window. I plan on removing the HEPA filter I have in the exhaust flange. That may have something to do with the air not fully making its way out of the box. At least I am hoping that is what it is. Man I hope so. It makes good sense tho. The air pulls from the box goes through the short ducting (about 1.5 feet) then hits the HEPA filter and bounces some of the air back into the box. That might be the issue. Will find out early today and keep you posted.

Otherwise I was thinking a swamp cooler or just adding an intake fan on that 3rd intake (the one running to the outside) and pull more air from the outside into the box. Lets try removing the HEPA filter and see if that helps. If so, I wouldnt need that intake fan. TBH again I am perplexed as to why the Vortex fan is not powerful enough to cool my 3.5 X 3.5 X 6.5 box.

coreywebster · Dec 11, 2017

Yeah it sounds like the HEPA is seriously restricting airflow, if your still having problems after you remove it then draw a little diagram of your whole set up and we can work out the simplest solution.

PetFlora · Dec 11, 2017

I hope that's a blue light filter on your camera

Babies benefit from having red also for root development

and that is way too much deep blue

You need to educate yourself on color spectrums during various stages of growth

Start here:

https://www.heliospectra.com/blog/forgotten-spectrum-and-importance-green-light-crop-quality

hth

RayRay747 · Dec 12, 2017

RayRay747 said:
Hey - i actually did the intake ducting about 3-4 days ago because the temps increased. I felt maybe if i drew in cold air from the outside it would help lower the temps. But that didnt work. So my other thought was something was obstructing the ducting before the air made it through the exhaust hole and out into the basement. I dont feel much of the air coming out of the end of exhaust which only runs about 4 feet and vents right out of the top. The basement stays around 60F almost all year long so I still dont get why it wont cool off. The only time when the temps are optimal are when I only have the VEG switch on. When I do both VEG and BLOOM all of the idealness goes out the window. I plan on removing the HEPA filter I have in the exhaust flange. That may have something to do with the air not fully making its way out of the box. At least I am hoping that is what it is. Man I hope so. It makes good sense tho. The air pulls from the box goes through the short ducting (about 1.5 feet) then hits the HEPA filter and bounces some of the air back into the box. That might be the issue. Will find out early today and keep you posted.

Otherwise I was thinking a swamp cooler or just adding an intake fan on that 3rd intake (the one running to the outside) and pull more air from the outside into the box. Lets try removing the HEPA filter and see if that helps. If so, I wouldnt need that intake fan. TBH again I am perplexed as to why the Vortex fan is not powerful enough to cool my 3.5 X 3.5 X 6.5 box.

coreywebster said:
Yeah it sounds like the HEPA is seriously restricting airflow, if your still having problems after you remove it then draw a little diagram of your whole set up and we can work out the simplest solution.

So as suspected, the HEPA filter I put in the flange was impeding the airflow. Man what a HUGE HUGE difference. Temps now with both Bloom and Veg switches on is at 70.6F and 44.8% RH. I disconnected the air flow from outside and am now just pulling from the basement. When it was pulling from the outside, the temps dropped into the high 60s F. So I will connect that during flower to drop the temps down even more to help out with the flower stage.

Im stoked now. lol. It was such a simple oversight on my end. Something I thought was going to help with keeping shyt from exiting the grow box and getting into the basement actually ended up being detrimental. So the only thing I have now is a bug mesh on the end of the 5' ducting that is connected to the exhaust flange. That bug mesh is meant to keep bugs from going into the exhaust ducting. I also have a bug mesh on the exterior vent where I will be pulling air from the outside. I kept the HEPA filters and bug mesh on my intake vents and just added some carbon filters to help with scrubbing the odors that may seep thru the intake vents for any reason. I know the bug mesh, HEPA filter and carbon filter inside the intake vents add some resistance to the fan pulling the air in but I think those filters are good to have.

So right now temps being steady at 70F and RH at 45%, I am guessing the temps will drop to 60F. If I turn off the Vortex at night that will probably keep the temps from dropping so much and will keep the RH on the higher end. My box is insulated very nicely so the heat should stay inside the box as long as a lot of the basement cold air is not coming inside the box (which shouldnt as the vortex is turned off). Ill have to see how it goes tonight. I have the fan and humidifier turning off with the lights now (until flowering - when I will have the fan running 24/7), so lets see how the temps and RH react to that.

Its so funny that I had one problem (heat) and fixed that and now have the opposite problem (cold). just too funny. I am trying to determine the best way to tackle the cold now, since the basement always stays around 55-60F during the winter and 60F during the summer.

RayRay747 · Dec 12, 2017

PetFlora said:
I hope that's a blue light filter on your camera

Babies benefit from having red also for root development

and that is way too much deep blue

You need to educate yourself on color spectrums during various stages of growth

Start here:

hth

Yep I understand the spectrums during the stages of growth. I have the lights on VEG but sometimes put both VEG and BLOOM on to get more light intensity. Was tackling heat issues but with the help of some peeps here was able to diagnose the issue - the HEPA filter on exhaust was seriously restricting airflow exiting the grow box.

I think the blue you might be seeing in the reflection off the walls from the humidifier in the corner. I might be wrong tho.

coreywebster · Dec 12, 2017

Nice one RayRay, glad you got it sorted out. Happy growing.

RayRay747 · Dec 12, 2017

coreywebster said:
Nice one RayRay, glad you got it sorted out. Happy growing.

Thanks much. Looking forward to seeing the rewards by February with these autos.

My only issue now is figuring out if I need to pH my water if it drops to around 4.8-5.0 pH after adding molasses, aloe vera juice and coconut water. It starts out around 7.8 out of the tap and after I boil it and add a half orange to the water it drops to 7.4-7.5 pH. Now add the stuff above and it drops to that 4.8-5.0 pH level. Should I water with that (I would say no), or should I adjust pH using baking soda or another organic alternative?

Same thing with the plant food, it drops the pH down. What do I do when feeding the plant food?

Everywhere I read I am seeing so many different statements and opinions, but I was hoping to get facts so I was going to call Coast of Maine today and ask them what I should do when using their soil. Id guess they would know best than all of the different opinions. Most of the opinions I do see heavily favor not pHing the water (like never), but I cant find anything specifically stating when you SHOULD pH adjust the water.

Gooeyhoney · Dec 12, 2017

Help Please w/ LED Lighting: Veg vs Bloom Switch vs Increase in Temperature

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