# When to lower temps for purple strains



## pje07 (Jul 14, 2008)

How many weeks before harvest should I lower temps at night for purple strains?? Ive kept the temps around 74 throughout the veg and flower so how many degrees should I drop it?? Should I drop temps during the day a little too?? How long should I keep dropping temps before harvest??


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## ouizer (Jul 14, 2008)

In my experience with purples the bulk of color change happens in the last 1/4 or so of the flower cycle.Lowering temp has biggest affect during this time not as much before.Plant maturity is tied to color also.I try to keep my room at 60 or below if possible.Keep the temp as low as possible 24 hrs a day.


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## mountianstar (Jul 15, 2008)

ouizer said:


> .Keep the temp as low as possible 24 hrs a day.


thats not good advice, he was right in saying that they get the last bit of color near the last few weeks of flowering though...(usually in the last 2-3weeks of flower)

If you would like a purple color its best so start with a strain that turns a purple color. If you would then like it to be more colored by temp changes (which do really nothing for the bud but make it grow worse because of low temp conditions)

The best way to do that is to lower the daytime temps in the room to around 60F. Then @ night you want it to drop 10 to 15 degrees lower than the daytime temp to a temp of 45F-50F

I would actually suggest finding better genetics though for the best purple colors without having to screw around with temp changes. Having a cold or hot room lowers yields terribly and is actually the most common factor for low yields.
Im growing this strain out in my room now, it got this purple in a room that was 78 degrees Fahrenheit. Pm me if you want more info on this general subject or the strain Im growing


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## stucklikechuck (Jul 17, 2008)

my experience is lower it 10 degrees during the final few weeks of flowering (lower it during the light off period). i have a grand daddy purple urkel hybrid that is very nice purple color. i will post pics of them when i can...


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## bleezyg420 (Jul 17, 2008)

mountianstar said:


> thats not good advice, he was right in saying that they get the last bit of color near the last few weeks of flowering though...(usually in the last 2-3weeks of flower)
> 
> If you would like a purple color its best so start with a strain that turns a purple color. If you would then like it to be more colored by temp changes (which do really nothing for the bud but make it grow worse because of low temp conditions)
> 
> ...


 and if you like hermie plants.... alter temps.


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## headbandrocker (Jul 17, 2008)

if the purple your talking about is granddaddypurple it will flower on its own at the end without ac.Good luck


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## stucklikechuck (Jul 17, 2008)

headbandrocker said:


> if the purple your talking about is granddaddypurple it will flower on its own at the end without ac.Good luck


 
ive had GDP not turn purple in the summer so sometimes that is not always the case.


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## mountianstar (Jul 17, 2008)

stucklikechuck said:


> my experience is lower it 10 degrees during the final few weeks of flowering (lower it during the light off period). i have a grand daddy purple urkel hybrid that is very nice purple color. i will post pics of them when i can...





headbandrocker said:


> if the purple your talking about is granddaddypurple it will flower on its own at the end without ac.Good luck


did you two not see this picture? The plant was in a room of 75 dgree temps its WHOLE life.



bleezyg420 said:


> and if you like hermie plants.... alter temps.


you are exactly right. If you want a purple strain get some purple genes and they will do it all on their own.


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## doctorD (Jul 20, 2008)

Its so true. temps have little effect on color. Nor does age. So lowering the temps for the last 2wks is just a bad idea. It wont do a thing good for your color. Its all in the plant


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## mountianstar (Jul 20, 2008)

doctorD said:


> Its so true. temps have little effect on color. Nor does age. So lowering the temps for the last 2wks is just a bad idea. It wont do a thing good for your color. Its all in the plant


+rep for someone else that knows what they are talking about


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## Dirtyboy (Jul 20, 2008)

purple weed strains turn purple on there own. Even if ya lower the temp on a non purple strain just the leaves will purple not the bud


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## pje07 (Jul 22, 2008)

Thanks go out to everyone for the great info.


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## mountianstar (Jul 22, 2008)

mucho welco


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## ouizer (Jul 23, 2008)

Been growing purple urkle since it was created and grand dad not too long after, I have sold thousands of clones of the same and gotten many reports back.Don't know about other purp strains but neither one is guaranteed to turn purple.I live in an area where the temps are frequently in the range I quoted at harvest time and the plants do great.I imagine weed wouldn't grow in the high mountains if temps were so detrimental. But then I am talking about outside at the moment.I do know though that the ppl who have gotten urple from me and growing it indoors that have trouble getting good color are always more successful when they get thier temps lower, and when I am on my indoor cycle I find the same.I don't find any diference in yield or quality and regularly get well over .5 grams per watt.


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## mountianstar (Jul 23, 2008)

ouizer said:


> Been growing purple urkle since it was created and grand dad not too long after, I have sold thousands of clones of the same and gotten many reports back.Don't know about other purp strains but neither one is guaranteed to turn purple.I live in an area where the temps are frequently in the range I quoted at harvest time and the plants do great.I imagine weed wouldn't grow in the high mountains if temps were so detrimental. But then I am talking about outside at the moment.I do know though that the ppl who have gotten urple from me and growing it indoors that have trouble getting good color are always more successful when they get thier temps lower, and when I am on my indoor cycle I find the same.I don't find any diference in yield or quality and regularly get well over .5 grams per watt.


If you are lowering your temps below 70oF then you ARE hurting what you could be yielding. The reason that the bud turns purple when you lower temps is because that strain also has the bud change color when you fuck with temps. Just like some strains leaves change when you lower temps.
TONS of people can get close to .5 grams a watt, thats only HALF of what you should be aiming for, so your yields are jeopardized whether you believe it or not.
.5 grams for every watt of a 1000 watt light is only 500grams....I know people that pull a gram per watt flowering straight away as soon as clones root....(and their weed is purple because they are growing good genetics

Thats also affected by how long you veg though so the yield quote is really info that shouldent be brought into this discussion.

My point is that if your growing and you want a *definite* purple color you need to go with a strain that will deliver that. If you lower temps your fucking with the plant natural life cycle and stress the plant. Lowering temperature affects food production in the leaves as well as transpiration processes. If you want I can bring a bunch of experienced people in here to tell you that you are indeed misinformed. Ive been doing this for long enough that I know EXACTLLY what Im talking about...


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## Istaysmoking (Oct 11, 2008)

doctorD said:


> Its so true. temps have little effect on color. Nor does age. So lowering the temps for the last 2wks is just a bad idea. It wont do a thing good for your color. Its all in the plant



what are you talking about? lots of strains go purple when you lower the temps. Its not unsafe at all. and maturity has lots to do with it SMH at you saying that


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## doctorD (Oct 12, 2008)

Its true temp can have some effect but its small at best. I have found its mor a ph thing. A plant has to have the tendancy to go purp or it wont matter it just wont go from green to purp. Its not just marijuana that reacts like this. Look at azalias (not close on spelling) the color on them is directly related to ph. So I have been doing some testing. If you lower the ph a bit it will get a deeper purp color.


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## oldhippy54 (Oct 12, 2008)

_*ok my plant seems to grow faster when i stash it in the bathroom with just 2 cfl bulbs going*_??? it is greener and developed 3 more leaves over night i counted 13 this morning ....any explanations for this? the temp stays around 72 f. i am puzzled over this but i have read about growing outside with only natual light and fluctuating temps. i have no idea what strain this is.


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## freddythekruger (Oct 12, 2008)

mountianstar said:


> If you lower temps your fucking with the plant natural life cycle and stress the plant.


what??? it gets cold outside in the fall at night. that sounds pretty damn natural to me. damn you mother nature for being unnatural!


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## doctorD (Oct 12, 2008)

ok i wanted to put this with my last post but my cam was acting up. 2 different strains here but you can see how purple the one is. I have had other cuttings even a much darker richer color all from just a bit lower ph. not one difference in temps so its the plant not the temp.


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## gamereaper (Sep 25, 2011)

just for the record ( yes this post is old ) coming from grand daddy purple him self states that temp brings out purple colors only if its in there genetics. Also some are auto purple too.


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## mike91sr (Sep 27, 2011)

lol, first post is a dug up thread from 3 years ago. Nice


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## OldGrowth420 (Sep 28, 2011)

what strain is this buddy?


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## dragun (Sep 30, 2011)

first you want a plant with purple genetics(gdp,purple urlke,pk).drop the temps to 60 for 2 hours a day for the last three weeks.

ive harvested gdp with no purple during the summer months with out a/c.and 100%dark purple during winter months.


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## oHsiN666 (Oct 1, 2011)

ive seen purple strains NOT turn purple! its possible. ive seen GDP NOT turn purple.


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## GangusKush (Dec 24, 2016)

First plants I ever grew outside got snowed on in the last 2 weeks of flower , for 48 hours they were exposed to 30-35 degree temps and they went from bright green to deep dark purple, the two plants were banana kush and pineapple express, note that most of the trichomes were striped in the freezing temps


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## j00ster (Jan 2, 2017)

the last 2 weeks of flower lwt temps fall on the dark phase.


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## dankness19 (Oct 24, 2017)

I've heard that I'm trying on plants just to see.


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## Dr. Who (Oct 26, 2017)

doctorD said:


> Its so true. temps have little effect on color. Nor does age. So lowering the temps for the last 2wks is just a bad idea. It wont do a thing good for your color. Its all in the plant


I agree with all of you that say, "Don't change temps!"

I never alter my lights on temps. Night gets to as low as the seasonal ability of my heat to kick on. That is held to a 10 deg. drop.
I run everything at 72 deg. F and cooling holds that to a 2-3 deg rise....Rh is set for 45%.

I have found over the years that balancing the nutrition ratio to like 4-6-6 and adding a K supplement (K sulfate) of 6% and increasing to 12%, then stopping at week 6-7 (2-3 weeks before harvest) _does_ encourage more color expression in strains that can. I get some nice colors out of plants not "normally" thought to. I do run longer than most I see around here. Not much but, it matters to end quality - greatly!



doctorD said:


> ok i wanted to put this with my last post but my cam was acting up. 2 different strains here but you can see how purple the one is. I have had other cuttings even a much darker richer color all from just a bit lower ph. not one difference in temps so its the plant not the temp.


Dropping temps at night, can have adverse effects too. Slowing of growth by limited up-take from cold roots and coloring from that resulting "def." Outdoors in cooler climates get this problem. Lends to airy and less density, smaller finishing buds....

I bet @doctorD, you don't get much drop at night either, or like I do.....


There you go kiddies. A straight answer to an old thread, can be good......


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## vertnugs (Oct 26, 2017)

Purple......waaaaay over rated.


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## kingzt (Oct 30, 2017)

Dr. Who said:


> I agree with all of you that say, "Don't change temps!"
> 
> I never alter my lights on temps. Night gets to as low as the seasonal ability of my heat to kick on. That is held to a 10 deg. drop.
> I run everything at 72 deg. F and cooling holds that to a 2-3 deg rise....Rh is set for 45%.
> ...


What's the lowest temps you would go when the lights go off? My room goes from 76f to 68F when lights go out. Haven't ran into problems this run but wondering if I should increase/decrease temps when they go off.


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## Huckster79 (Oct 30, 2017)

I prefer to finish cooler, just to finish cooler. 70 high 60 low at harvest... i start out upper 70s till half way through plus a bit then about 3 weeks out i start lowering temp bit by bit..


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## Dr. Who (Oct 31, 2017)

Once you start to get below 60. Things you don't like can happen.

To be more detailed. Once the roots and soil around them, begin to drop below the 60's. The plant starts to have problems up-taking some nutrients. The longer this happens with them in the light. The more pronounced the problems. Being able to warm the soil around the roots fast, can help. Potted plants moving in and out for night and day. Prolongs the period of outdoor plant life. Thing is, days getting colder, makes for pots less able to stave off the cold around them - it's the sun warming them that keeps the temp up.... 

Colder temps make for loose budding, nutrient up-take problems, and slowed growth rates.

Coloring aside, not good for plants, especially the roots to get below 60......


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## chemphlegm (Oct 31, 2017)

same temps year round, my purple strains turn purple.


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## trinketswittrichs (Nov 8, 2020)

Lowered temps but, I didnt do it on purpose,it was outdoor funny thing was, i saw other random plants turn purple also ,then the leaves and buds turned


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## kovidkough (Nov 8, 2020)

I wonder how large the purple genetic gene pool is now 12 years later


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## Star Dog (Nov 8, 2020)

I'm on blackberry lol its looking nice and purple, for the record I believe it's maturity not temperature related.

Incidently it was a purple strain I was growing 12 years ago, I got the mother as a clone I don't have a clue what it was but it was top notch, what were the popular purple strains back then, a long shot but I just might recognise the name if I seen it.
Anyone?


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## Star Dog (Nov 8, 2020)

chemphlegm said:


> View attachment 4035758
> 
> same temps year round, my purple strains turn purple.


What is that strain buddy? 
It looks lovely!


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## Op-era (Mar 1, 2021)

The only reason a plant would turn purple besides genetics would be, is if you were causing nutrient lockout and phosphorus deficiency. So if you like tiny purple buds, make it cold. If you want big purple buds, find the right strain.


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## Star Dog (Mar 1, 2021)

IMHO lowering the temperature below ideal is never a good idea, if it's a purple strain it'll colour up near the end. 
They colour up in the summer just fine when it's warm 24hrs. 

Each to there own but retarding a plant for colour isn't my thing I like to keep it moving forward. 





kovidkough said:


> I wonder how large the purple genetic gene pool is now 12 years later





Star Dog said:


> What is that strain buddy?
> It looks lovely!


I never thought to check the date posted. .
We live and learn lol


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