[doob]

So winter is around the corner, and this means some of us will be worrying about cold conditions very soon. I grow in an external building, so ambient temps have a big effect on my groom.

I have built a box which my pots sit in. This will then have a heater in it keeping the pots a nice temperature. I also have a tank heater to go in the reservoir.

So my question to you is, what would you say the optimum temperature for the roots/medium is and what temperature the reservoir should be at. I am thinking of setting both up at 20-21degC (68-70degF)

And lastly, what is the lowest temperature i should let the canopy drop to, if i have the roots at the optimum temp?

Thanks

[jewcebox]

anything over 70 in the res will have algae grow i believe

[Snow Crash]

I like my roots between 60f and 68f (~16c to 20c).

You want your canopy temperature to stay in a narrow range. Don't let your low temperatures drop more than 10f (5c) below the daytime temperatures for best results.

Your reservoir should remain cool to improve the dissolved oxygen capacity. I also keep this between 60f and 68f (16c to 20c) like my root system.

[doob]

Thanks for the replies. That is interesting looking at that graph, much appreciated. 16degC - 20degC it is, I can set the tank heater to 16degC and monitor the temperature with a probe i have. I will have to do some testing with the heating when it is all put together this weekend.




I will aim to keep the red box >16degC 24/7. The yellow area will drop when it is lights off obviously, i will have to see what sort of temperatures i am getting and go from there I think

[Pumpkin]

Your tank heater set at 20C should do the trick. The box seems unnecessary. Your lights should be enough to heat up the room. Feed just before lights on (1 hour-30 mins) and get them warm before the growing starts. At lights off I would not bother heating the roots, the plants are not doing a lot of growing at night anyway. What's your outside temps? How cold are we talking?

I've never had issues, but my nights only really hit -4C, if you are colder than that perhaps more extreme measures may come into play, but I'd still be trying to increase lights on room temperature rather than heating the roots only.

Don't worry about algae. Algae needs light so won't be in your res anyway. If it's growing on the top of your coco, don't give a shit either

[doob]

My set up is in a single skin external building, intake temperature will be low soon. Probably average 5-10degC through winter, perhaps some cold spells at zero. Ideally i would insulate the tent and warm the intake I know, but where it is it cannot be done successfully, I would be chucking away money trying to heat it up.. I grow autos because of this issue, so lights off will be short, I can even leave them on 24/7 all though I have never tried that past week 4. I use blumats so they will be constantly dripping when needed

[stoned40yrs]

I don't have sealed or heated rooms and deal with Alaska cold air all winter. I can tell you this for sure- when the root zones in coco get into the 40s and 50s you will get nute lockouts in the plants. Single best tip if you grow in colder rooms is to elevate the plants off the floor. Cold air sinks. Milk crates work good so we are talking at least 12-14" off the floor. I try to get 60 lights off and res temp of 60 for the blumats. Lights on I grow with 70-75 at top of the canopy. Some days my rooms are sucking in air that is way the hell below zero, lots of fun growing in winter here

[doob]

Yes i bet you have a right battle over there! Interested how you keep temps so high on lights off though. The box I have made will be insulated and sealed, the pots will slip in and I will stick a tube heater in there. That should keep them nice and toasty downstairs. Mine are raised on insulation etc before the tent, then they will be off the floor so it should keep them nice i hope

[jewcebox]

will you be draining runoff out of boxes? heat and humidity + darkness= mold

[Bush Dr]

Air temperature is not as important as humidity

I've had one of my best crops ever with the temperature of the intake fan reading-10C, as long as you keep the root zone in the 18-22C you'll be fine, just make sure they can drain properly ......the buds were so hard they ripped the pins out of a grinder and very potent too