Cold basement grow tent help needed.

[iruleyou1]

I run about 900w of cobb LEDs in a 5x5 grow temp and I am fighting low grow tent temperatures when lights on and colder at lights out. I'm starting to tinker with the idea of running HPS just for the coldest winter months. Outside of that what are my options? Here is what I tried with mixed results.

Placing an oil heater in the tent doesn't work well because the ventilation fans just cycle air in fast.

Do I need the ventilation fans during lights out besides to control humidity. Is there any reason to cycle air regarding C02 or oxygen levels at night.

I'm thinking about putting a fan controller and slowing them down to min cfms needed during lights on. I did go with oversized fans because I was having humidity problems big time in the summer.

I hate to say it but running 2 600 watt hps would probably be more efficient than using a cobbs and the heater and I bet it would bring my temps up more.

 

[Flagg420]

may not work for all, but i vent my veg room into my flower room to keep temps up at lights off...

how bigs the grow room? That will determine if theres enough fresh air 'overnight'

 

[rob333]

I run about 900w of cobb LEDs in a 5x5 grow temp and I am fighting low grow tent temperatures when lights on and colder at lights out. I'm starting to tinker with the idea of running HPS just for the coldest winter months. Outside of that what are my options? Here is what I tried with mixed results.

Placing an oil heater in the tent doesn't work well because the ventilation fans just cycle air in fast.

Do I need the ventilation fans during lights out besides to control humidity. Is there any reason to cycle air regarding C02 or oxygen levels at night.

I'm thinking about putting a fan controller and slowing them down to min cfms needed during lights on. I did go with oversized fans because I was having humidity problems big time in the summer.

I hate to say it but running 2 600 watt hps would probably be more efficient than using a cobbs and the heater and I bet it would bring my temps up more.

running a hps is 10x betters its only the u.s.a thats in a craz about leds no other country is you cant even buy them anywere in my country not one hydro shop will stock them if you ask about leds you get laughed out the door

 

[iruleyou1]

running a hps is 10x betters its only the u.s.a thats in a craz about leds no other country is you cant even buy them anywere in my country not one hydro shop will stock them if you ask about leds you get laughed out the door

Yeah the typical premade LED arrays are garbage. I made mine and yielded one ounce less than 3lb in my 5x5 last grow. I have 16x 54w cobbs drawing under 900watts actual watts. I blew the gram per watt benchmark out of the water so it definitely works. The one thing I like better about cobbs is the light spacing and more even canopy. I notice in my veg tent with a cmh my veg plants grow lopsided since the light is focused in the center. Most store bought LEDs don't draw the power they stamp and they get a terrible light spread

 

[iruleyou1]

may not work for all, but i vent my veg room into my flower room to keep temps up at lights off...

how bigs the grow room? That will determine if theres enough fresh air 'overnight'

The basement is 800sq feet and the tent is 5x5. The basement has plenty of fresh cold air so I am just wondering if I need to leave the tent fans on at night so if I place a heater in the tent I just don't blow all the heat out. I was wondering if the fresh air is mostly important during photosynthesis? I understand I may need to run a cycle timer for humidity if humidity rises.

 

[rob333]

Yeah the typical premade LED arrays are garbage. I made mine and yielded one ounce less than 3lb in my 5x5 last grow. I have 16x 54w cobbs drawing under 900watts actual watts. I blew the gram per watt benchmark out of the water so it definitely works. The one thing I like better about cobbs is the light spacing and more even canopy. I notice in my veg tent with a cmh my veg plants grow lopsided since the light is focused in the center. Most store bought LEDs don't draw the power they stamp and they get a terrible light spread[/QUOmy local hydro shop still kills any led with hps they are given they use a basic 400w grow lush lamp and the last led lights they got were from unit farm a pre built cob thing from a u.s builder a timber cali light works and kind ranging from 500-900w

 

[rob333]

cali light works was by far the best but who wants to pay 900-1200 on a light when were i live u could fit a whole grow room out with 2 600w hps lamps 2 inlines a air con a tent all the nutes and still have money left for a carton of beer and a bottle and a high class stripper

 

[rob333]

cali light works was by far the best but who wants to pay 900-1200 on a light when were i live u could fit a whole grow room out with 2 600w hps lamps 2 inlines a air con a tent all the nutes and still have money left for a carton of beer and a bottle and a high class stripper

you could prob pay some asian here to grow it with whats left from that wile u sit on the beach and do fuck all

 

[rob333]

you could prob pay some asian here to grow it with whats left from that wile u sit on the beach and do fuck all

and pull 4.2 a p

 

[Chip Green]

First of all, one question....
Has this "low temps" situation had any negative effect on plant health?

 

[1212ham]

FWIW, I think the nutes need to be different in the cold. The plants transpire less and that's an effect on nutrient uptake.

I think hps would be more efficient than running a heater. And keep in mind, I'm an LED guy.
HPS has a lot of IR and that heats the plant directly.
Plants under LED like higher air temperature due to the lack of IR heating, typically around 27-29°C.

I've been planing grow box of foil faced, foam insulation board,1 inch thick. Heat loss calculated to something like 75 watts for a 2x2x5.
I hope to keep air exchange low enough to keep the heat and humidity without the co2 getting to low, but might have to add co2.

https://www.rollitup.org/t/growing-in-cool-temperatures.980364/#post-14610528
https://www.rollitup.org/t/how-much-air-exchange-do-you-need.105781/#post-14616501
https://www.rollitup.org/t/growing-in-unheated-garage.980062/page-7#post-14604938
https://www.rollitup.org/t/setup-for-growing-in-cool-temperatures.980362/
https://www.rollitup.org/t/infrared-heatlamp.981071/#post-14628409

 

[pulpoinspace]

FWIW, I think the nutes need to be different in the cold. The plants transpire less and that's an effect on nutrient uptake.

I think hps would be more efficient than running a heater. And keep in mind, I'm an LED guy.
HPS has a lot of IR and that heats the plant directly.
Plants under LED like higher air temperature due to the lack of IR heating, typically around 27-29°C.

I've been planing grow box of foil faced, foam insulation board,1 inch thick. Heat loss calculated to something like 75 watts for a 2x2x5.
I hope to keep air exchange low enough to keep the heat and humidity without the co2 getting to low, but might have to add co2.

https://www.rollitup.org/t/growing-in-cool-temperatures.980364/#post-14610528
https://www.rollitup.org/t/how-much-air-exchange-do-you-need.105781/#post-14616501
https://www.rollitup.org/t/growing-in-unheated-garage.980062/page-7#post-14604938
https://www.rollitup.org/t/infrared-heatlamp.981071/#post-14628409

not to hijack the thread but quick question that might help OP too:

when plants transpire less, does that mean they need a higher concentration of nutrients?
i know if its hot and dry they need less nutes and more water

reason i ask is i've been dealing with 72-75F lights on and 60-65F lights off, 40-50%RH. i thought my plants were getting nutrient burn so i keep feeding them less and less. they're peak flower now only getting .9EC. luckily around here it only gets "cold" like this for a couple months out of the year. ill probably pick up an HPS for next year.

 

[coreywebster]

may not work for all, but i vent my veg room into my flower room to keep temps up at lights off...

how bigs the grow room? That will determine if theres enough fresh air 'overnight'

I used to do that too, your the first other guy ive come across who does it.
Works great for keeping night temps up.

 

[coreywebster]

I run about 900w of cobb LEDs in a 5x5 grow temp and I am fighting low grow tent temperatures when lights on and colder at lights out. I'm starting to tinker with the idea of running HPS just for the coldest winter months. Outside of that what are my options? Here is what I tried with mixed results.

Placing an oil heater in the tent doesn't work well because the ventilation fans just cycle air in fast.

Do I need the ventilation fans during lights out besides to control humidity. Is there any reason to cycle air regarding C02 or oxygen levels at night.

I'm thinking about putting a fan controller and slowing them down to min cfms needed during lights on. I did go with oversized fans because I was having humidity problems big time in the summer.

I hate to say it but running 2 600 watt hps would probably be more efficient than using a cobbs and the heater and I bet it would bring my temps up more.

Yeah having some extra wattage would obviously raise temps but it wont help for lights off temps.
A day/night fan temp controller would be a good investment, you can set temps and at night fans will idle , you can also plug an oil filled heater into them which will work when fans are running idle.
Also worth insulating the floor under the grow space.

What sort of temps are you dealing with? What cfm you running and are you seeing issues currently?

 

[Thegermling]

Everybody says to switch to hps for warmth in the winter but what about when the HPS go off

 

[iruleyou1]

I read the post about using a fan controller for at night but is it ok to shut off all intake. Thats my question.

As for the cost of my LEDs mine are DIY and about $550. In the summer on the reverse side I did not need to run an AC at all so it had a savings. Also I don’t need to buy replacement bulbs every 6m to a year.

The reason I asked this question is my plants were having symptoms of deficiencies. The only things that changed is the time of year being colder and drinking less. I added a res heater since the water was 52 and that already helped. At night temps are mid 50s and lights on about 70 max. This grow is definitely stunted.

What I did that seemed to help is shut of the exhaust fan and leave the intake on half speed with a 700 watt oil heater in front of it outside the tent. It still has enough power to force air out the exhaust. I hit 80 but we also had unusually warm weather here in the NE.

I use 2 450 cfm fans so they are overkill. I will get a second fan controller so I can slow both down and not have the tent look like a baloon

 

[OldMedUser]

My grow room is in cold basement so I have many of the same issues. After 16 years of growing in there this is what I do.

Temp/RH and speed controller on my 6" inline exhaust fan and a heater on a baseboard thermostat for night time. Not an oil filled heater either as they take too long to warm up and supply heat then take too long to cool down. The heater I'm using now would work perfect in a grow tent. It's 24" wide, 16" tall and 4" thick. It's like a baseboard heater in a box. The heat comes out the top and with a 16" fan circulating air in the room 24/7 the heat is constantly blown around the room. Two 750W switches with only one on keeps the 7x9x6.5'h space heated just fine at night with the lowest temp around 69F. During the day I can keep the temp around 75 tho I go higher when adding CO2 with an alcohol lamp.

I still plan on using that 500W baseboard heater mounted on the wall but didn't realize when I bought it that it's a 240v unit that barely got warm when I wired it up for 120v. Eventually I will set it up but the box heater works just fine for now.



I use HID lights as I need the heat during the day. With one 400W only the heater has to kick in once in a while during the day in there in winter but mostly I'll have 2 of those or a 1000W going which is enough to keep the heater off. During the summer it can get up to 64F in the basement so one 400 is enough to heat the room enough for the fan to kick in and draw in fresh air. All the air coming into the room is from the rest of the basement and filtered so I'm not getting warm or icy air from outside. No AC needed.

With the controllers on the exhaust fan once the light goes out the fan will only kick in if the humidity goes above the setting it's at. It may kick in as the room cools and the RH spikes even tho there is no more moisture in the air, humidity

relative so the RH reading goes up as the air cools. The fan won't come on the rest of the night so warm air from the heater stays in the room where it belongs.

If I was using a tent I would trip on down to the thrift store and find a couple of cheap comforters to blanket the tent with to insulate it so it doesn't cool so quickly at night. I have an 8x4 tent but if I set that up downstairs every time I opened the flaps to work on the plants it would be flooded with air as cold as 40F in the winter. I have plans to add an 8x4 grow space attached to my current grow room but it will be 8x6 so I can enter thru a door that can be closed behind me and have space to work on the plants. Some reflective curtains will keep the light in the 4ft wide area.

Do I need the ventilation fans during lights out besides to control humidity. Is there any reason to cycle air regarding C02 or oxygen levels at night.

No.

 

[Merlin1147]

I’m in a similar situation and put a Mini electric heater. Lasko 101 200 watts plugged into an ink bird. I have passive air intakes and I ducted those up to the ceiling where any warmer air would be and put filters and cloth over them. I’m assuming your running the exhaust for odor and or air exchange. I throttle down the exhaust fan all the way down. That combined with the filter and cloth makes for a lot on negative pressure but it’s working for my situation.

 

[Merlin1147]

running a hps is 10x betters its only the u.s.a thats in a craz about leds no other country is you cant even buy them anywere in my country not one hydro shop will stock them if you ask about leds you get laughed out the door

Yup and I’m sure there was a time the rest of the world felt the same way about radios, Television, Microwave ovens, cell phones, computers and grow lights. Many thanks Thomas Edison.

 

[Thegermling]

I’m in a similar situation and put a Mini electric heater. Lasko 101 200 watts plugged into an ink bird. I have passive air intakes and I ducted those up to the ceiling where any warmer air would be and put filters and cloth over them. I’m assuming your running the exhaust for odor and or air exchange. I throttle down the exhaust fan all the way down. That combined with the filter and cloth makes for a lot on negative pressure but it’s working for my situation.

How big is your grow area? I have a lasko that has two heat settings. The first uses up 800watts while the 2nd is 1500. I also have an inkbird hooked up to it. Does that mini heater heat up a 4x4 well?