QB boards and COBs in winter? Are they warm enough?

[Colo MMJ]

I am still on SE HPS but finally may start making a move toward QB. My idea was to keep some SE HPS for winter and do a mix.

The question is - are QB's and COBs warm enough in winter? Say at night the outside is below zero. The somewhat insulated building would probably be close to 40 F with no heat on. Can you run space heaters in the room to get it to the 70 to 78 deg F range? Do the plants need radiant heat from the lights?

I know COBs can put out some heat but QB's are pretty cool to the touch? Thanks.

 

[Rocket Soul]

Those conditions dont sound real led friendly, sealed room or vented? Whats the reason to switch to led? Power savings, quality, hype? My friend grows in similar conditions at winter and led dont work out well for him. Maybe upgrade to DE? Plants metabolism is affected a lot by temprature, low light but right heat is usually better than intense llight but way too cold. Theres some graphs floating around here on riu on how temps and light intsensity affect metabolism.

 

[ANC]

You can grow fine in winter, just switch to DWC or aero so you can control root temperature with a small aquarium heater in the water supply.
Otherwise, make sure to lift all your bags/pots off the ground so they don't sink all their heat right back into the ground.The main problem is vegging, during flowering with a room full of COBs at full power, you welcome the cold as much as with any other platform.

 

[Rocket Soul]

The good and bad thing about hps is the infra red: in low temp it heats up the leafs directly with out having to spend energy to heat your whole space, in high temps you have to cool your space extra in order to get your leaf temps down. Some people use laser temp readers to get an idea of what leaf temps work for them.

 

[ANC]

 

[SoOLED]

it depends on what area. tents help a lot, but like an open concrete floor might have problems if ambient temps are below 75f.

 

[nevergoodenuf]

I have found, for my room, a combo of sealed and vented works best for me. Winter, with 2000w of COBs, I run semi-sealed with a dehumidifier to help maintain low 85* temps with CO2 and have the fans only turn on if humidity spikes or temps get above 87*. At lights out, the dehu is off, the CO2 is off, and the fans kick on only if needed.
During the summer, I don't use the dehumidifier, but only the fans for humidity and temp control. If I can't maintain 80* without CO2, I will turn on the Mini-split.

 

[shannonball]

you'll want to figure out a way to keep the roots warmer than the floor temp, look into heater pads or something along that line that keeps them at a constant temp.
Our 950watt cobs put out some heat but it all rises to the top of our grow shed and towards the end of our grow, which was about 2 weeks ago, the shed was ~70-5F near the plant tops, but the roots were in the 50-60s which is our minimum temp.

 

[Ryante55]

If your heat is well controlled at 1000w just get 1000w of quantum boards an it will have the same heat with more light

 

[Colo MMJ]

The good and bad thing about hps is the infra red: in low temp it heats up the leafs directly with out having to spend energy to heat your whole space, in high temps you have to cool your space extra in order to get your leaf temps down. Some people use laser temp readers to get an idea of what leaf temps work for them.

Great responses from all posters thanks.
+100 about keeping them off concrete and making sure root ball is not too cold. We are running tupur with multiple DRIPs with water kept at about 71 deg F. Is that too cold for a DRIP.

This may be the key point here. I assume buy phasing out say SE HPS for more COBs - I could add a small space heater - though that burns more electricity. I can run my propane CO2 which generates a bit of heat and keep the door closed.

The leaf temps and spectrum like infra red is closer to my real question. The HPS will keep the plants warmer.

 

[Kerovan]

Yes they are, watt for watt they are just as warm as hps.

 

[Kerovan]

My 260W hlg quantum board is not cool to the touch at all. I cannot put my hand on the heatsink for more than a few seconds without burning it's so hot.

 

[CobKits]

last year i threw one of those shitty dehumidifiers from the big box stores right inside my tent lol

 

[Rocket Soul]

Yes they are, watt for watt they are just as warm as hps.

Indeed they are, in a completly closed system. I tend to think about infrared a bit like lenses for cobs: its a way of getting the heat where you want it (or dont want it in case of too hot). Cobs create heat that rises to the top of your grow thru convection (unless water cooled or similar) which is good if you have heat problems but not so much for cold grow room.

 

[GreenLogician]

Cobs create heat that rises to the top of your grow thru convection

I have cold grow room problems much of the year. Maybe if I exhaust out of the bottom of the tent, instead of the top?

 

[ANC]

Can you run space heaters in the room to get it to the 70 to 78 deg F range?

https://www.rollitup.org/t/the-hygrostat-thermostat-combination-device.940136/

I'm working on a Peltier based system to keep shit cold in summer and hot in winter. You just switch polarity.

 

[Moflow]

Indeed they are, in a completly closed system. I tend to think about infrared a bit like lenses for cobs: its a way of getting the heat where you want it (or dont want it in case of too hot). Cobs create heat that rises to the top of your grow thru convection (unless water cooled or similar) which is good if you have heat problems but not so much for cold grow room.

I use a 4" fan and suck the warm air from the ceiling to the floor.
I've 4 plants under flower under cold conditions right now. They are sitting on top of a 100 watt heat mat.
Lights off temps are 10 - 12oC in the canopy.
Lights on temps are around 22oC.
When I was an HPSer I'd stick an extra light in for heat on lights on and a oil filled heater for lights off.
I've never lost a plant to cold conditions indoors even when the temps were -8oC in the day and -14oC at night over a few weeks.
As long as they don't freeze

 

[Humple]

I use a 4" fan and suck the warm air from the ceiling to the floor.
I've 4 plants under flower under cold conditions right now. They are sitting on top of a 100 watt heat mat.
Lights off temps are 10 - 12oC in the canopy.
Lights on temps are around 22oC.
When I was an HPSer I'd stick an extra light in for heat on lights on and a oil filled heater for lights off.
I've never lost a plant to cold conditions indoors even when the temps were -8oC in the day and -14oC at night over a few weeks.
As long as they don't freeze

You don't have nutrient uptake problems at such low temps?

 

[Moflow]

You don't have nutrient uptake problems at such low temps?

They are looking ok at the moment.
Obviously it's not optimum but they'll be moved into a warmer area in December.
I usually line the pots with polystyrene lining paper when it gets colder so the medium inside doesn't suck in the cold.
@ANC is right about running hydro in winter to keep the roots warm and the chill outta the room. Aquarium heater is great for that

 

[Stephenj37826]

Really like the Mercury 4 from Titan controls. Insulate the room mote and run a space heater. Run the lights during the days if you run into temp problems. Let the heater keep the temps up during the lights out. You can seal the room as well to help. You'll need a dehumidifier of course which will add heat a well. Transversally run the lights at night in the dealer room and slowly exchange air during the day (lights out).