ideal temp?

I know this must be a question that has been asked a million times, but couldn't find anything on it in the forums, but probably just missed it.

So, what is the ideal temp for a grow room, specifically a closet grow. Is there a difference between ideal temps for vegetative and flowering?

THANKS in advance!

70-75 degrees F is ideal for all stages of growth regardless of the size of the room, hope this helps

go past 85 and growth could be stunted, sorry not sure of the conversion

TheCheeseMan said:

70-75 degrees F is ideal for all stages of growth regardless of the size of the room, hope this helps

Click to expand...

I thought that 80-85 would be good for veg cause MJ plants grow faster at that temp, and cooler for flower to get those dank nugs. I could be wrong though...I just keep my grow room as cold as possible.

well anywhere between 65-85 is ACCEPTABLE. anything outside that stunts growth. i like to keep mine 75ish. gives u plenty of buffer either way. but ideally 72-77 constantly would be great.

Are you guys talking about ambient or radiant temperatures? My ambient (room temp) is always higher than the radiant temperature. This is why I use both a standard thermometer, and an infrared temperature gun to get exact canopy temps.

I had my largest production to date when temps were 60 degrees at lights off, and 75 with lights on. Also a colder dark period has been proven to increase color contrasts in bud, aka make it more colorful.

With out co2

Day temp 75-78

Night 73

With co2 of 1000ppm +

Day 83-85

Night 75

Last 2 weeks - 10 days cool the room as much as possible, down to about 70 day and 60 night, to get the plant to think the end is near and get some good color and crystal.

Thats what i have found gives the best results, and is based on trial and research.

The hoter the temp the faster the metabolism, until you reach the peak when any hotter and it starts to slow growth, this peak is at a higher temp when using co2 hence the different temps. Also a drop in temps at night is beneficial (some say it isnt) but i have found a small drop is better than no drop.

Another point is to try and have as little variation in temp for the whole light and dark cycles, and crop, consistency is key.

Row

ideal temp is that which can be maintained in own environment. the domain and range of plants is very broad.

in this imaginary garden temps are kept high on purpose, day and night.

w/ lights on, ambient temps are 78-88*f, and can get up to 100+ easily, when additional lights are turned on.

begin fruiting w/ 85*f day/80*f night.
then 85*f day/85*f night
then 80*f day/88*f night
@ 1hr before lights on, turn temps to ~60-65*f.
then 72*f day/60*f night @ 8/16 light cycle.

if have good ac/de-humi, check difference between gallons transpired w/ higher temps vs. lower temps, and amount of water roots have drawn in. more water seems to cycle thru eco-system w/ higher temps.

higher temps promote greater metabolism, respiration and transpiration - as long as dehumidification is occurring and air flow is voluminous, can go up to 100*f.

plants generally register temps @ photoperiod changes. @ dawn can trick plant into thinking had a long cold night by lowering temps to 60-65*f; when really had lights on temps of 88*f. this registers in plant as 60-65*f night, though have had benefit of much higher temps, actually.

@ mid-flower, make night temps higher than day temps (negative diff).

then positive diff (warmer day temp than night temp) to finish.

if really interested, try in own garden... plant senses average day/night, and weekly temps, and acclimates to general weather pattern, just like any other living organism. either plant will adapt to regime, and thrive; or suffer.

try 1 week w/ lower temps (65-75*f), then try 1 week w/ higher temps (75-85*f). these are the generally accepted 'low' and 'high' temps. neither regime will kill plants. observe differences, if any. take note of rh differences, if any. also, take note of differences in water uptake from roots. then decide which temp regime will work for own garden.

the surrounding vapor pressure (relative humidity) also affects how plants respond to higher temps. cooler temps squeeze water out of air. higher temps hold water in air.

if plants are transpiring more due to higher temps, more water vapor in air. remove humidity so plants can push out water into surrounding atmosphere. water vapor is pressure upon leaves (stomata). stomata regulate internal temp of plant, and gas exchange w/ environment.

there are many variables in deciding 'ideal temp'. some variables garden/er/cultivar specific. some plants thrive in high temps, some may not. most do. the natural regions of high mountains/deserts/low valleys of 100+*f temps (over many centuries) have made many species quite adaptable to dry, hot temps. some equatorial plants may desire higher rh, like in grassy/swamp areas.

any plant can be made to adapt to what the garderer desires. those that dont survive are not strongest genotypes.

enjoy your garden!