Terpenes lost due to high growing heat?

I was reading a lot of stuff on LED lighting on here the other day and a lot of people kept saying that the LED grown buds tasted better and had richer smells than same pheno clones grown under HID.

I've heard the same thing said about outdoor grown weed as well.

I'm also personally experiencing a problem where every kind of weed I grow has a very similar smell and taste with a few exceptions and I also know my heat is probably too high.

It seems logical that excess heat while growing could explain a lot of that. Terpenes boil off at all different temps and it could be that some of the most delicate are being burned off in hot growing conditions.

I sat down and devoted some time and did a big search online and looked for credible sources and recorded every temp I could find that were posted as minimum, maximum and ideal for growing. They varied all over the place needless to say so I had to average.

I averaged them and came up with:

Maximum peak temp while growing to not exceed: 29C (84.2f)
Ideal normal growing temperature: 25c (77f)
Minimum temp at which growth will occur: 15.5c (60f)

I'm starting to think those are too high and I'm losing terpenes.

What say you?

de145 said:

I'm also personally experiencing a problem where every kind of weed I grow has a very similar smell and taste with a few exceptions and I also know my heat is probably too high.

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Major reason for everything tasting the same... nutrients and how you're using them.

- Avoid overfeeding
- Flush for a week to 2 weeks, depending on your strain


As for heat? Best buds come out from under HID's (for me) when temps don't exceed 75F.... That, and the plants are backed away from the light for 7-10 days before chop.

Stay Safe!

Hydro-Soil said:

Major reason for everything tasting the same... nutrients and how you're using them.

- Avoid overfeeding
- Flush for a week to 2 weeks, depending on your strain


As for heat? Best buds come out from under HID's (for me) when temps don't exceed 75F.... That, and the plants are backed away from the light for 7-10 days before chop.

Stay Safe!

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So in terms of terpenes and heat t I think what you are saying is you agree that heat can kill terpenes with your comment about backing away from the lights before the chop.

de145 said:

I'm also personally experiencing a problem where every kind of weed I grow has a very similar smell and taste with a few exceptions

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I had that problem.


Do you have little black flying bugs?

I did. --- VERY VERY BAD SIGN!!!!! That is usually heavy infestation time - they can be in the plant roots with no noticaeable flyers


Are your plants looking a little rough? Kinda like a previously unkown defficency or summtin?

Do they tend to droop after the lights have been on awile?

Mine did.

And they all had "THAT SAME BASE SMELL"

If this is sounding too real,,, you may be dealing with Root Aphids.

Leme go get you a link to a thread or two........

whatcha growing in?


I'm in rockwool cubes

Heres a thread with decen pics - not mine the other guys! lol
https://www.icmag.com/ic/showthread.php?t=237149

Quick question, how does outdoor that can see 100+ deg. F taste so good and get you very ripped? I have done in and outdoor and not sure if temps alone are responsible for terpene loss. I think having a full light spectrum does a lot for flavor, along with organic cultivation or living soil.NS

If you can smell it, terps are evaporating. If they did not, smell would have likely been stronger. Peace GS

ime heat doesn't effect much beyond how the plants grew. as for the smells and tastes being lost i find that is often the result of wrong ratios of nutes being applied. too much nitrogen can hinder trichomes and smell production as well as increase flowering times. not enough magnesium will lead to smaller calyxes it seems. etc etc. i have grown with avg temps in the mid 90's and aside from foxtails and or airy buds, the smells were still there and trichomes were there, maybe the strain but the higher temps seem to get greasier trichomes vs sticky.
plants in the wild use up their stored nutrients by harvest. i try and mimic this indoors for the best weed. after the main flush of flowers is over. somewhere in week 6-8 i stop all nutes and it's just plain water till the end. nitrogen is cut out by the end of stretch.

whilst i agree that there are many factors that go towards producing aromatic weed, i think the high radiant heat from HID lamps does contribute significantly towards terpene loss, especially of you keep the lamps as close as possible to your canopy - for most people this is simply too close - if your upper leaves are canoeing and the ends are curling upwards then thats a sure sign of light/heat stress.
unless you are measuring your canopy temp very carefully then you might not be getting the full story.
i have generally found LED weed to be more aromatic than HPS weed, and ive always put it down to either better spectrum or less radiant heat battering the canopy - quite possibly both

VG

With the same clone , soil and nutes , have noticed certain odours are much more pronounced when grown under cfl and led , than under sodium.

From what i have seen , it is influenced mainly by temperature and not the differing light spectra , strawberry is one that seems easily lost with high bud surface temps .

Hey VG, it was actually some of your posts (which I highly respect for their thoughtfulness) on LED growing I was reading that led me to the heat hypothesis.

I see people mention too much N / nutes a lot. I have ruled that out by going to extremes after experimenting with using as few nutes as possible to the point of almost deficiency showing and smelling no difference in terpenes whatsoever with the same clones.

Also I grow in soil and water by submersion of the pots in a bucket. I only need to water once or twice a week that way, they never show stress as a result but perhaps they *should* dry out a lot more to stress them into producing more terpenes?

I'm going to try minimal surface watering with a control group and see if that accounts for anything terpene related.

I'll also try molasses as indicated, I did try them when I was growing organic and to be honest never noticed any difference in smell, flavor or composition of the plants between organic with molasses in the water and my current non organic nutes.

Perhaps in the end I just haven't run into awesome pheno's from the seeds I was growing however in at least one case I know that outdoors the same cutting was much tastier and smellier using the exact same organic grow medium I used indoors for the same plant so I still don't feel like nutes are the answer to this problem.

I guess there is no clear cut consensus and most think it's nute related. I'm going to experiment with moving a control group of plants further away from the lights to a cooler spot in my cab during the flush period just to confirm for certain if there is any difference.

Also I'm going to completely revisit my harvest and cure process, perhaps I'm missing something big.

Any other ideas people have I'd appreciate as I will experiment and report back on anything that I can do that is suggested.

Hey RMH, no bugs, I did have thrips once but took care of 'em and this problem has plagued me for a while now regardless of thrips or over or under nutrients or anything else.

The only thing whith that is the plants can grow faster the higher the temp is. When mine hit 90 degress as long as though theres no other limiting factors they grow a lot faster than at 78 degrees. Its down to choice then though it might mean sacrifising yield for taste and potency.
I find headmasta helps with smell and taste.

Green Supreme said:

If you can smell it, terps are evaporating. If they did not, smell would have likely been stronger. Peace GS

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Good point. I'll employ my nose more in the grow cabinet at various stages and add that to my records.

Hydro-Soil said:

Major reason for everything tasting the same... nutrients and how you're using them.

- Avoid overfeeding
- Flush for a week to 2 weeks, depending on your strain


As for heat? Best buds come out from under HID's (for me) when temps don't exceed 75F.... That, and the plants are backed away from the light for 7-10 days before chop.

Stay Safe!

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yup he said it right there

Also proper dry and cure helps with flavor after the chop. dont jar it to soon.

To add to that I find people that use phosphorous additives usually use way to much. If I use any at all I use about 1/5 the recommended amount and only leave it in from day 12 to 14, and that's it. Then flush for 1 or 2 days. If you use more or longer it stunts your buds. It also keeps them from changing color at the end, which means that is still has lots of built up phos in it, and that effects the flavor too. you want them to be changing from green to purple, or yellow, or red, etc.

I've grown under much hotter conditions and had tasty shit, with different flavours.. This was indoor soil or chemical DWC. Also had clone strains i know well done by mates indoor hydro organic and by me in outdoor organic and the indoors although awesome are missing a whole section of fruit terpenes. So.. In conclusion, if your plants seem happy, look at their soil (or whatever) or your nutes maybe. Some nutrient manufacturers put essencial oils, sandalwood and others in their nutes so your shit will taste like chronic guaranteed! haha I wondered for a while why every ones shit had that same floral taste till I smelt it in the nutes Just sayin.. Do a bit in some good bonemealed, limed and guano'd composted homemix, mixed with coir, perlite and or verm, worm castings, alfalfa and kelp, dolomite sand and mushroom compost. Introduce beneficial fungi. Feed with compost teas and worm castings, humic acid, fulvic acid, vitamin B complex and molasses. Flush for 14 days and cure your buds. You will taste things that you have never tasted before regardless of your growing temps..
Your average temps sound like my average temps when I had an aircon running years ago, it gets hot here.. Also UV makes ganja make oils IMO, inverse square for lights so closer they are to a threshold the more UV. Oils are made up of many terpenes including aromatics and cannabanoids.. When I walk into an outdoor patch in the hottest part of the day when the air is still and it is baking, it smells like a skunk has died. The plants get so greasy and just ooze out stuff to protect themselves from the light and diffuse it more effectively through prisming and lensing through the trichome heads to take advantage for photosynthesis. So no I reckon something else. How are you drying it? Although, like I can do blind taste tests of my babies and their progeny and still tell lineages etc even if i dry slow, quick, fan, no fan, dehydrator, no dehyd, top of TV, brown bag.. etc.. No, must be soil, nutrition in general or your nutrient brand. Research those things.. In my home country there was a chicken brand with the catch phrase, 'they taste so good cuz they eat so good'.. Yup. Also plants use the light directly and specifically so light spectrum I suspect is more of a culprit than heat as I also notice flouro weed is tasty and Very strong, but fluffy haha. Water in rez was too warm for my liking, had to put mylar over the black tote tops to stop them getting too hot, but made plants hotter. Rez's had an air compressor making a jacuzzi of bubbles so oxygen was there always.

Genetics and food. Cheese smells like a skunks ass and tastes like yummy yummyness no matter what you feed it or how you grow it. But do all you can do with regards to nutrition and growing enviroment and it will be another animal. I have seen an outdoor cheese yeild a K clean of the most ridiculous stinky, smelly, greasy, stuff with ONE month veg period only. It is all in the diet. Check ph's too cuz maybe something important is maybe being locked out and supplement with epsom salts. Also check root health with regards to locking stuff out, the roots must breathe, airpots and the likes rule!

de145 said:

I see people mention too much N / nutes a lot. I have ruled that out by going to extremes after experimenting with using as few nutes as possible to the point of almost deficiency showing and smelling no difference in terpenes whatsoever with the same clones.

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did you go the other direction? using too much nitrogen? i can assure you the buds will come out like this.


and won't taste or smell like anything but dried grass.

northstate said:

Quick question, how does outdoor that can see 100+ deg. F taste so good and get you very ripped?

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Is it 100F when you chop? I doubt it.


Yes... turpene life span and heat seem to be inter-related. I'm guessing that the infra-red from HPS destroys a lot of the more fragile turpenes. Would explain why CMH growers often describe slightly higher potency... sometimes with more complex smells... for the same cut.

Stay Safe!

northstate said:

Quick question, how does outdoor that can see 100+ deg. F taste so good and get you very ripped? I have done in and outdoor and not sure if temps alone are responsible for terpene loss. I think having a full light spectrum does a lot for flavor, along with organic cultivation or living soil.NS

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the soil is not 100 degrees. I grew out side in texas fro years and took soil temp a foot down and it was 70 degrees.

Also by the time it starts to flower temps max out in the 80's in the air

ambient heat and radiant heat are two different things. your ambients might be real nice but up there in the canopy with yer 600 a few inches away the buds can be cooking.

nearly all the pics of un-topped plants i see posted tend to show that 'centrefold' cola sticking out the top of the plant with it's upper leaves canoeing and the tips curling up to the light. that is heat/light stress... and thats the bud that the grower will generally keep for themselves

VG