Lights Off....Strong Smell.

LetricBud

LetricBud

Active Member
Okay... so most of the time when you have your grow system running the room/area is filled with a mild skunky odor, depending on strain and whether or not you have it filtered.

But for some reason, whenever my lights turn off, my system emits a very strong "Planty" smell. Its not the regular weed smell... not even skunky, just planty.

I've noticed it takes about 1 week in flower for plants to start really doing this, but it has occurred slightly in veg as well.

The smell is not exactly cut grass, but not really cut flowers either. If you've ever pinched your tops, then you might recall the smell of your fingers when you did that. That's what it smells like. I'm amazed at how fast it occurs after the lights are off and how strong it is, but I'm confused as to why this is happening...perhaps something to do with the pores on the leaves.

I'm using a 3x3 tent, 400w HPS, FF Soil, FF Base nutes, KoolBloom supplement. They are 2 weeks into 12/12. The lights turn off at 6:50pm, by 6:52 you can smell it across the room.

Just wondering if this is natural, and if anyone else had encountered this.
 
S

sm0keyrich510

Active Member
i have gotten this smell too...i think it matters on the strain since during some grows ive smelled that same smell and others i havent...note: ive never grown the same strain twice...so idk for sure if its the strain but at this point its my educated guess as for the most part my system/way of growing stays the same.
 
jhopkins34

jhopkins34

Active Member
Maybe, it has something to do with the soil? Do you water when you turn the lights off? I could see,when the light is on the soil would be fairly dry and usually not too smelly, but as it gets wet and slightly more like mud it may release more of an odor. Just an original guess, I work more with hydro, and haven't noticed a more planty smell as the lights go off, but I have a much stronger carbon filter then needed for the area so I very rarely notice smells pre flower and even during flower it remains quite light.
 
Total Head

Total Head

Well-Known Member
i am familiar with the smell you're talking about, but mine isn't really a "lights off" smell. i noticed that my plants (regardless of strain) usually smell in cycles, and the smell is strongest about 2-3 days after a watering or feeding. the "plant" smell i notice more right after the plants are watered, and it's not the soil. the soil stops having a detectable smell after a couple weeks of use. a friend of mine noticed a long time ago that one day he would come over and claim i'm stinking up the neighborhood, and the next time he asks if i harvested already because the smell is gone. as far as whether this is good or bad or neither, i'm not sure.
 
LetricBud

LetricBud

Active Member
It isnt the soil or watering issues...I water usually every 3 days right when the lights turn on. The smell starts occurring right when the lights turn off...

I have 2 different strains, and ive smelled this even when they're seperate.

its just strange....its like right when the lights go off, someone switches on a big "Plant Smell" generator in my room. The smell is not really that noticable a few hours after the lights go off...but from about 6:50-10:00 pm the place stinks of plant...it almost smells like green apple peels.

When the lights are on, it smells of standard dank.

I am just wondering the science behind this...something to do with pores on the leaves opening and closing during the light schedule.
 
ANC

ANC

Well-Known Member
Its realy amazing to observe plants and light.
I used to do planted aquariums, and unless you realy had a solid buffer, switching off the lights at night would alter the pH by several magnitudes of order as the plants start pumping out CO2 (an acid).
 
LetricBud

LetricBud

Active Member
yep...plants are cool.

I like how it seems like they dont ever move...but they just move very slowly. So you dont notice when they start messing things up.
 
Mr Botanical

Mr Botanical

Member
Bringing an old post back to life. What you are smelling is Chlorophyll. From what I understand, when the sun goes down (lights out), the plant inhales CO2 but exhales Oxygen and Chlorophyll. Some say the level of Chlorophyll released depends on how much light has been absorbed during the day. If the plant is getting heavy/too much light during the day, it will exhale more Chlorophyll at night. I've been noticing this a lot recently when switching from 200w CFL to 600w HPS. The smell was minimal on my 200w CFL but really strong after the 600w was turned on for late vegetation stages. Apparently, it doesn't exhale Chlorophyll all night long; just in the first few moments of lights out. I'm no expert, but this is where my research on 'lights out smell' has led me.
 
Last edited:
Unclebaldrick

Unclebaldrick

Well-Known Member
LetricBud said:
Okay... so most of the time when you have your grow system running the room/area is filled with a mild skunky odor, depending on strain and whether or not you have it filtered.

But for some reason, whenever my lights turn off, my system emits a very strong "Planty" smell. Its not the regular weed smell... not even skunky, just planty.

I've noticed it takes about 1 week in flower for plants to start really doing this, but it has occurred slightly in veg as well.

The smell is not exactly cut grass, but not really cut flowers either. If you've ever pinched your tops, then you might recall the smell of your fingers when you did that. That's what it smells like. I'm amazed at how fast it occurs after the lights are off and how strong it is, but I'm confused as to why this is happening...perhaps something to do with the pores on the leaves.

I'm using a 3x3 tent, 400w HPS, FF Soil, FF Base nutes, KoolBloom supplement. They are 2 weeks into 12/12. The lights turn off at 6:50pm, by 6:52 you can smell it across the room.

Just wondering if this is natural, and if anyone else had encountered this.
Click to expand...
Yep, happens every time. Just after curfew. But the smell is predominantly chlorophyll rather than dank. Smells just like a fresh cut lawn. I do not know why. I ran a massive filter continuously with air cooled hoods. The hoods are sealed so I can't see any blowback out of the lamp cooling line occurring. It has been a mystery to me for a while.
 
orbo

orbo

Well-Known Member
Brought this back from the archive because the OPs question it is the exact same question I have going thru my mind. I put my girls in flower last week and they started doing this...this is not the first time I've noticed but it is the first time that I thought to myself I would actually like to try and understand what is going on. Anyone?
 
DesertGrow89

DesertGrow89

Well-Known Member
Not sure If this has been mentioned yet but it s more than likely due to high humidity... Had the same problem until I invested in a dehuey

It's due to transporation, plants releasing vapor into the air
 
orbo

orbo

Well-Known Member
DesertGrow89 said:
Not sure If this has been mentioned yet but it s more than likely due to high humidity... Had the same problem until I invested in a dehuey

It's due to transporation, plants releasing vapor into the air
Click to expand...
I am running a steady 35% 24/7. I'm thinking its not high humidity causing it, I think. @DesertGrow89 - I think transportation is likely involved somehow, just wondering about the details of said activity. Here's another thread where this phenomenon is discussed. @legallyflying has a reasonable answer but really it appears as though its his/her best guess at what it might be. Still looking.
 
DesertGrow89

DesertGrow89

Well-Known Member
orbo said:
I am running a steady 35% 24/7. I'm thinking its not high humidity causing it, I think. @DesertGrow89 - I think transportation is likely involved somehow, just wondering about the details of said activity. Here's another thread where this phenomenon is discussed. @legallyflying has a reasonable answer but really it appears as though its his/her best guess at what it might be. Still looking.
Click to expand...
Oh so it's due to respiration? I see
 
You must log in or register to reply here.
Top