Temperature/ Humidity

Optimum tempurature during vegetation time i find is about 80 degrees f and around 55 % humidity. For flowering i find the tempurature should stay around the same if not mabye a little cooler 78 degrees mabye with humidity around 40 % to prevent mold .

Why cant a plant survive 95? I mean shit man plants do it all the time outside. Like pot plants can take a beating by heat.

At about 91 degrees f, your plant will cease to grow. Yes naturally in areas it will get hotter than that. But to ensure constant growth, you will need to keep it under 90.

I have not much knowledge about indoor growing, only grow my seedlings and clones indoor with 24/7 light and 100% rh. Asap they go outside where they fight temp ranges from 50F to 110F. Nothing seems to stop them from growing, nothing seems to stop them from flowering. The only difference I have noticed is during cold spells the leaves grow short and very broad and during heat waves the leaves strech and grow very thin. I think mainly due to high/low UV and humidity levels, not down temperature. I cannot tell what ideal temperatures and ideal humidity are but I have not experienced anything negative in this range as long as your water, feed and airflow is abundant but not too much.

IMO, it doesn't matter as long as temps are not too extreme, they're somewhat consistent, fluctuate between "day/night", and most importantly, you react to any extremes. just read this thread and you'll see what I mean below. Successful grows with temps and humidity all over the spectrum in the replies here.

If the temps spike higher than 90F, they need more water, feed them more. If the temps get too low like 50F raise the temps. Indoor I try to maintain 85F +-4F lights-on, and 70F +-5 lights off but that's just a guideline for me. However, I also have to deal with summer temps up to 90-100F outside (in turn raising temps inside), and winter temps as low as 0F, in turn colder inside. If it's too hot, I try to cool it down, and read the plants/increase water requirements as needed. Too cold, I heat to maintain lights-off temps above 60F.

As far as humidity, I try to maintain 45-60% during veg., 30-40 during flowering to avoid mould issues more than anything. But even this is "ideal" and plants will do just fine if you get spikes here & there.

I've gone indoor recently but have grown 5-6 footers ("christmas trees") in those extreme outdoor temps, getting 6-9 dry/cured oz/plant, dependant more on strain than anything else. Typical outdoor daytime temps 70-90 during June-August, typical day temps during Sept/October in the 60-70F, and night temps as low as 40-45F. Always pick them around mid-October before the first significant frost.

Remember we're growing weed, keyword *WEED*, these things can take a lot of abuse. The key is balance and all the factors combined. Think basics...
** Lots of air-flow around the plants and fresh air exchange (air)
** Not over or under-watering (water)
** Sufficient lighting, it doesn't matter what type, CFL, LED, HPS, HID, key is enough lighting for the size of grow (light)
** Deal with extremes as well as you can and adjust to the conditions, it's not rocket science, don't complicate things

2 cents….

In a single loft grow I've hit temps of 35 and 105f. Still pulled 16 oz from a 600w.

you guys are too precious. Choose the right variety and you can get away with murder. Northern Lights is bomb proof, so is Durban Poison, Strawberry Cough, Sleestack, OG Kush, Swazi and many others. Fuck temperature but beware of humidity. Too high = mould. Otherwise, just go for it.
I've had ten ounce yields off one NL plant using 500w LED, B&Q grade veg ferts, one inline fan attached to a filter and, in flowering, nothing more than a good dose of potash of sulphate twice during the flower stage.
This is regular seed raised in a 10 inch pot filled with 30/70 coco/generic potting mix.
I think LED gives a slightly smaller yield than HPS but it's worth it because the heat footprint is non existent.

oh and the temps ranged between 20c in light to 15c in dark.

Oh, and make sure you snip the fuck out of every branch as it appears. That way you get a huge bush...like madonna's

When I started growing indoors 5 years ago, after a 20 year succesful outdoor hobby, I used to lie awake at night wondering of the humidity was right, if the PH was accurate, if I was using the right nutes,
Then, three years ago, I said 'fuck this, do what you did when you were getting two pounds per plant outdoors!,
So I did. I went back to basics, kept an eye on the girls and fixed things as they happened.
Yes, you get some strains that are right assholes, but fuck them, there are other strains just as good that will perform.
It always makes me laugh how indoor people always try to make this growing lark something incredibly difficult. It's not.
Follow these rules:
1: Good soil
2: Hardy variety
3: Fertilise once a fortnight
4: Flush a week before flipping lights
5: POTASH OF SULPHATE it works for thick stems and heavy buds, it's the bollocks
6: Tip every new growth during veg

Try it and tell me I'm wrong.

My current grow now 4-5 weeks flower after 6 weeks of vegging rarely saw temps out of the high 60's. I know it slowed them down some but they seemed to get accustomed to it. Its slowly warming up now into the low 70's and they're flowering nicely. Humidity was low as well so I had to mist them in veg, but I never do that in flower. I've had bud rot before and ever since then once buds begin to develop they dont get misted anymore.

I am running at about 73-79 on and off with a humidity of around 55-60. I know the temp is perfect but is my humidity ok or should I lower it my plants seem to be doing great but this is my first time and I know nothing about this but what I have read and on the humidity I have read a lot of mixed feelings with it

Proper temperature is one highly variable factor. Most books state optimum grow temperature to be 70-80 degrees, but many list extenuating circumstances that allow temperatures to go higher. Assuming genetics is not a factor, plants seem to be able to absorb more light at higher temps, perhaps up to 90 degrees. High light and CO2 levels could make this go as high as 95 degrees for increased growth speed.* An optimum of 95 degrees is new data that assumes very-high light, CO2 enrichment of 1500 ppm and good regular venting to keep humidity down. It is not clear if these temperature will reduce potency in flowers. It may be a good idea to reduce temperatures once flowering has started, to preserve potency, even if it does reduce growth speed. But higher temperatures will make plants grow vegetatively much faster, by exciting the plants metabolism, assuming the required levels of CO2 and light are available, and humidity is not allowed to get too high.

With normal levels of CO2, in a well vented space, 90 degrees would seem to be the absolute max, while 85 may be closer to optimum, even with a great deal of light available. Do not let the room temperature get over 35 C (95 F) as this hurts growth. Optimal temperature is 27-30 C (80-86 F) if you have strong light with no CO2 enrichment. Less than 21 C (70 F) is too cold for good growth.

Low temperatures at night are OK down to about 60 degrees outdoors, then start to effect the growth in a big way. Mid 50s will cause mild shock and 40s will kill your plants with repeated exposure. Keep your plants warm, especially the roots. Elevate pots if you think the ground is sucking the heat out of the roots. This is an issue if you have a slab or other type of cold floor.

As temperature goes up, so does the ability of the air to hold water, thus reducing humidity, so a higher average temperature should reduce risk of fungus.

Contrary to many reports, high humidity is not good for plants except during germination and rooting. Lower humidity levels help the plant transpire CO2 and reduce risk of molds during flowering.

Studies indicate the potency of buds goes down as the temperature goes up, so it is important to see that the plants do not get too hot during flowering cycles.

My grow bible says temps about 75 are good, up to 85 are great, but over that is too much.

My temps are around 79-86 with a humidity of 35-40 in the day and at night 74 degrees with a humidity that goes up to 61. I have tried to get it lower at night but other than getting a 150$ dehumidifier witch I don't have room for or money lol I hope I'm good. My girls seem to love the Environment there in Because they are so pretty with nice fat tight buds. I have done some improvements since my last post that have helped with the lights on but off just can't figure out.