when is cold too cold?

When do you think it is too cold in the grow room? I don't normally have problems but I am growing inside my house in my basement where it's really cold, I do have heat down there but it's normally very cold, lights on its 70-72 and lights out normally 58-60 but it has dropped to 55 this week as it's been so could outside, I'm currently flowering and I am 15 days into it, everything looks good no plants look bad at all, I am also running a dehumidifier now to lower the hum and also increase the heat of the room without having to run a space heater that doesn't really heat much anyways, what's your thoughts on this, will my yield lack any? I've had previous very cold runs and have had a few plants have issues, I'm currently growing about 20 different strains all from feminized seeds

good question. the weather this year is fukin stupid. 10 degree one day then 50 the next! my temp/humidity gage said high 0f 86 low of 63 tonite. it monitors in a 24 hour period.... although Ive read that some strains you can really bring the purps out in the final weeks by dropping the temps!im about a week behind you on flowering, guess we'll find out huh!

As long as you keep the soil from freezing, your humidity in check, and air circulation good... You can drop into the low 40s with your canopy.

I have the same issues. I grow in my basement where its humid in the summer and cold in the winter. I use pieces of 3 inch think insulation that my pots sit on, and during the lights out I have an electric oil filled heater with a built in timer. My veggin tent has a heat mat under my babies that comes on when lights go out. That said, I disagree that 40's is doable. IMO they wont thrive to say the least that cold. I usually manage 72-75 lights on and as low as 62 or so at its lowest point. I wouldn't want to go much colder than that and expect good results.

Cobnobuler said:

I have the same issues. I grow in my basement where its humid in the summer and cold in the winter. I use pieces of 3 inch think insulation that my pots sit on, and during the lights out I have an electric oil filled heater with a built in timer. My veggin tent has a heat mat under my babies that comes on when lights go out. That said, I disagree that 40's is doable. IMO they wont thrive to say the least that cold. I usually manage 72-75 lights on and as low as 62 or so at its lowest point. I wouldn't want to go much colder than that and expect good results.

Click to expand...

Mine do just fine with lows of 43-48 with lights out and highs of 55-62 lights on. Growth hasn't slowed at all.

Just depends on your other factors. I made a thread about cold growing. I do it every year, indoor and outdoor. Doesn't affect yield either.

Well I just had this issue 6 weeks into flowering my temperature's dropped into the 40's and high 30's for about a week with lights off, and it definitely stunted the growth of my plants for about 10-14 days or so, I'm pretty sure I lost about 20% in yield.

Enigmatic Ways said:

Well I just had this issue 6 weeks into flowering my temperature's dropped into the 40's and high 30's for about a week with lights off, and it definitely stunted the growth of my plants for about 10-14 days or so, I'm pretty sure I lost about 20% in yield.

Click to expand...

What was your humidity and how was your circulation? Both of those combined with your lighting matter much more than temp.

Connoisseurus Rex said:

What was your humidity and how was your circulation? Both of those combined with your lighting matter much more than temp.

Click to expand...

Rh was 55%...1200w 5x5x7 tent 430cfm

Enigmatic Ways said:

Rh was 55%...1200w 5x5x7 tent 430cfm

Click to expand...

You're humidity was ok and your lighting good. Your circulation is the problem. Exhausting is good for drawing old air out and fresh air in, but the plants need a solid breeze with lights on.

An oscillating fan right on them removes the boundary layer from the underside of the leaves, allowing them to transpire much quicker and wicking away moisture.

When they transpire quicker, it allows photosynthesis and respiration to become more efficient and steady.

I don't even run an exhaust fan. I run strictly oscillating fans for that reason.

https://www.rollitup.org/t/cold-growing.896067/

There's the thread. I run like this every fall and winter. Partly out of necessity and partly out of preference.

i start seeing lockout when i get around 60f.

brimck325 said:

i start seeing lockout when i get around 60f.

Click to expand...

Temp does not effect nutrient uptake.

really! tell that to a hydro grower.

edit: i can post 100 scientific studies on the subject.

brimck325 said:

really! tell that to a hydro grower.

Click to expand...

I've grown hydro. As long as your res is above freezing and your canopy is kept warm under the lighting, nutrient uptake is unaffected.

Now, once you start entering the higher 90s and into the 100s... That's an entirely different story for an entirely different reason.

For what it's worth, any temp above freezing and 98 is perfectly fine indoors. Doesn't have to be set. Your growth is affected much more by other factors. If you want to run 50s, 60s, 70s, or whatever, you can. It's just preference.

If you don't believe it, try an outdoor grow. You don't have to take my word for it. Take nature's. Just gets annoying when people say cold growing can't be done.

outdoors is much different then indoors....the ground temp stays fairly stable during growing season. i know they grow at lower then recommended temps. but yes it does affect them negatively. google it.

Connoisseurus Rex said:

https://www.rollitup.org/t/cold-growing.896067/

There's the thread. I run like this every fall and winter. Partly out of necessity and partly out of preference.

Click to expand...

Wow First of all please stop feeding bad information To say that 50 - 55 your plants are doing ok there not
They actually have stopped growing metabolism has slowed , photosynthesis, had slowed the whole dam plant has slowed , There fore plant is not producing or growing
With temps in the 40's Tissue damage will start to occur @ 32 degrees water inside the plant will freeze

One should think of temperature as a plant throttle i guess for every 10 degree rise in temp the metabolic rate doubles so plant growth doubles to a point where one part of the plant cannot keep up
And again will stop growing

So with that all said one thing having temps drop down for a couple days will in fact slow growth its not wise if you can control temps but again growing out door we are set @ mother natures hand indoor you can control it

I think were talking indoor here any who if the air is to cold and humid, you can also run into issues of mold and fungus
There is a reason plant species strive @ certain climates or can handle the cold better but they also been hardened over a long time

Now with everything Equal when growing indoor its best to study the strain and its region's temps, Relative Humidity, VPD, Wnds, rain fall etc and implement that into your room ..
following mother natures cycle and when plants most of the time get colder temps usally last 2 - 3 weeks in bloom but even then not going lower then 65 degree

Cause all your doing is stalling the plant many drop temps to increase color send a signal to plant that its tine to finish up ??? but again one must remember cold temps , Also becomes a decline in nutrient and water up take

2ANONYMOUS said:

Wow First of all please stop feeding bad information To say that 50 - 55 your plants are doing ok there not
They actually have stopped growing metabolism has slowed , photosynthesis, had slowed the whole dam plant has slowed , There fore plant is not producing or growing
With temps in the 40's Tissue damage will start to occur @ 32 degrees water inside the plant will freeze

One should think of temperature as a plant throttle i guess for every 10 degree rise in temp the metabolic rate doubles so plant growth doubles to a point where one part of the plant cannot keep up
And again will stop growing

So with that all said one thing having temps drop down for a couple days will in fact slow growth its not wise if you can control temps but again growing out door we are set @ mother natures hand indoor you can control it

I think were talking indoor here any who if the air is to cold and humid, you can also run into issues of mold and fungus
There is a reason plant species strive @ certain climates or can handle the cold better but they also been hardened over a long time

Now with everything Equal when growing indoor its best to study the strain and its region's temps, Relative Humidity, VPD, Wnds, rain fall etc and implement that into your room ..
following mother natures cycle and when plants most of the time get colder temps usally last 2 - 3 weeks in bloom but even then not going lower then 65 degree

Cause all your doing is stalling the plant many drop temps to increase color send a signal to plant that its tine to finish up ??? but again one must remember cold temps , Also becomes a decline in nutrient and water up take

Click to expand...

My plants don't mind at all. You can follow my grow if you'd like to see just how insignificant temp really is. Have you ever tried cold growing?

brimck325 said:

outdoors is much different then indoors....the ground temp stays fairly stable during growing season. i know they grow at lower then recommended temps. but yes it does affect them negatively. google it.

Click to expand...

As long as your medium stays above freezing, like I said, everything will be fine.

Connoisseurus Rex said:

As long as your medium stays above freezing, like I said, everything will be fine.

Click to expand...

This may work for you, however stating that type of gardening is the wrong way to go about things. Definitely those are not optimal conditions, and getting optimal conditions is what we as gardeners try really hard to do.