A/C Control - Night/Day Temps

Hi all,

What does everyone using a/c do to vary their night and day temperatures? or is it a case of just setting your desired temperature and leave it to do its thing by maintaining the set temperature all the time?

I've noticed some grow specific units use a photocell to determine if its lights on or off and dictate a different pre set temperature.

These units are usually more expensive which i don't see the need for if people are managing with normal A/C controls.

Thanks

I just set it and forget it on mine. If it gets too cold at night, I'll stagger tents so that they are on opposite light schedules. There's sometimes a 20 degree difference between day and night in there. Most plants don't mind.

When you say set and forget do you set it at one temperature and leave it meaning that there shouldn't be any difference between night and day?

I'm not sure i understand what your setup is unless you're running a/c outside of your rooms?

Oh, what I mean is that at night time the AC actually makes the room what I set it at, which is usually around ~65 or so. During the light cycle, while the thermostat in the AC reads that it's down to 65, cycling it off, the room, and especially the tents, are not actually 65. I would say the room is maybe 70-ish while the canopies are a few degrees warmer than that (in the case of a 1000w HPS, it was about 8-10 degrees warmer than the ambient air). So during the light cycle a plant might experience 78 degree day temps and 65 degree night temps. It's during the winter that this difference increases more drastically.

My setup is to have multiple tents, each with their own internal exhaust fans, inside of a basement bedroom that has a window unit in the window. I've thought about using fancy environment controllers before, for the purpose of being able to have less of a swing in temperatures between day and night, but I can't justify the price. In my experience, leaving the AC on all the time on a static thermostat setting hasn't negatively impacted the vast majority of strains I've grown.

I have found a few that absolutely did not like big temperature swings though, and in those cases I ended up staggering the two largest tents so that there was always an HPS of some wattage on at all times in the grow room.

Thanks, now i get what you mean.

Is there anyone running A/C in their rooms as opposed to a lung room that can offer their advice please?

I try to keep the differential between day/night temps to a minimum to help reduce stretch.

So does anyone set their A/C to different temps for night and day and if so how is this done through a standard a/c controller?

You could probably rig a "home programmable thermostat" to do that. The down side is that a thermostat is "time" programmable, not temperature dependent. IOW, the controlled variable is time, either day (lights off) or night (lights on) and not temp dependent. You are controlling a different set point based on "time of day". In turn the controller (thermostat) will control the temperature at the desired set point for "that" time of day.

To accomplish this make the output of your temperature sensor controller go to the "house thermostat". The output of the thermostat (signal) in turn goes to the AC unit.

IOW, instead of the AC being directly plugged into your "inkbird controller" you plug the thermostat to the inkbird, your AC is then controlled by the thermostat and not the inkbird perse. It is the time of day that matters here, not temp. e.g lights out which we want our temps to be 4-5 degrees F cooler. A house thermostat is programmed for "occupancy" or time of day. e.g lower temps at night or when no one is home.

So, how does this work? Set your thermostat to run 2 programs, one for lights on (night), and one for lights off (day) @ 4-5 degrees cooler and you should be golden. So if you want your optimum temp of lets say 78 degF, then program 1 (of the thermostat) runs during lights on and program 2 is set for 73 degF during lights out. In my surroundings, I run my lights from 10pm to 10am. Lights out from 10am to 10 pm. As seen here, although the programs has different set points, you are actually programming time of day. e.g cooler when lights are out.

I am sure there are some fancy dodads or programs out there than can do that but, at what cost? I use my study as a lung room (where my tent is situated) which, I ran my (window AC) at 66 degF during the hot days of summer, and 68-70 degF when lights were out. I hope this helps.

I own a few master grewnhouse controllers. I dictate my rh, temperature, and co2 levels (fuzzy logic). I sent them as the weeks go by.