Flowering Temperature Differential

[changeofpace2014]

It is my understanding there should be a 10 degree difference between day and nigh temps..I will be growing purple strains this time and really want the colors to show, however the lights are on over night when house temps are cool and hydro is cheaper. I am wondering if a few hours of a 10 degree swing would be enough to bring out the colors, or do they require the entire night..Just thinking ahead but the seeds are germinated and the race is on..

[3Berries]

My current indoor flower grow is GDP and a couple of weeks ago it got really cold enough I needed to turn on the heat. But still lower 60fs with lights off. The plant closest to the air intake turned really purple, the other didn't. So I switched them but have not had the cold snap yet again. They were in the stretchy phase then.

But it may be nute related as they needed an over all flower boost at that time.

[changeofpace2014]

I was really wondering if 3 or 4 hours of cooler temps (10 degree) swing would be enough to bring out the colors in flowering. The off hour billing cycle is 7pm to 7am here.. I would be willing to roll the timer back to come on around 4 pm and turn off a 4 am and this would provide 3 or 4 hrs with the 10 degree swing before the thermostat started to bring house temps back up. Our crawl space is concrete and there are about 6 hvac ducts through out the area and all of them have a damper lever to adjust..

I would not be able to swing that 10 degree differential when the house is 70 ish... I guess it is a waiting game, to see how the cold weather balances temps down there.

[changeofpace2014]

Thanks for the feed back...I suspect your observation was due to cooler temp and not a deficiency.

[3Berries]

It's a new soil for me ProMix BX. It much more dependent on adding nutes compared to the FoxFarm soils I have been using but they both have been getting the same nutes and water.

[Going2fast]

Temps aren't entirely necessary. Even newer photos don't need it. Autos definitely don't. I grew Tropicana poison and it flowered in July in 90 degree temps with purple buds. Same with Humboldt seed company squirt. Buds were purple but leaves stayed green. For older photos at least a ten degree drop at night is optimal during late flower but it needs the proper genetics. In my experience gdp is less than 50/50 chance of purpling even with colder temps.

[Mr.furley]

From my understanding there should NEVER be MORE then a 10 degree difference in temperature from day to night.

If you have a strain that changes color due to genetics it will happen without intervention. if you do not, in my experience you can sometimes pull color by dropping below 64f at night for a week or two.

I dont swing my temperature much more them 5°f if i can help it.

[changeofpace2014]

Thanks for the feedback..I will update this thread from time to time with progress...seeds with t/r are in 2 cup fab pot now, so now we wait..They will not be veg to long, especially with a 38" height restriction.