Does anybody dim their lights for the last week?

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Dogg1

Member
Hello all, I'm interested to hear it here, I like to dim my SP3000 to 25% last 5-7 days, seems to stack well and resin is always full. I will do this after the advertised flowering time for the plant, kinda hanging out and ripening for up to a week. ANY THOUGHTS?, {crazy, waste of time, nice, pointless}

.02$ COBs seem to benefit from this over SMD panels...(now I got your attention;))
 
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Dogg1

Member
Tolerance Break said:
I think good weed grown well is going to turn out good if you bring it to maturity with little excess/deficiency regardless of what happens in the last few days (outside of weather borne pathogens)
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What about excessive heat on the final week with terpene burn off, my thoughts along these lines are soften the impact on the plant and you'll have more expressive resins. Possibly a pipe dream..
 
Budzbuddha

Budzbuddha

Well-Known Member
Dogg1 said:
I was thinking a far red response kind of. Mimicking shade effect but with equal Spectra across the board.
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If it works for you then all good. Many garden “ tricks “ out there , like dropping light cycle from 12/12 to 11/13 ( preferred ) or even 10/14 ( which helps lagging flower or plants stalling ) by forcing flower. Some do drought stress during flower too ( actually works ) , bumping UV for resin production .

Again no rules.
I add pee , plants crave it.
 
Tolerance Break

Tolerance Break

Well-Known Member
Dogg1 said:
What about excessive heat on the final week with terpene burn off, my thoughts along these lines are soften the impact on the plant and you'll have more expressive resins. Possibly a pipe dream..
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I am of 2 minds.

Land of origin is so very important. I think a plant that has deep ancestry in warm environments are going to present differently than plants that traditionally reach maturity as the temperature drops, or lives its whole life where the temps are lower. If the best high comes with some terps being burnt off, then thats what I want.

On the other hand... I am not familiar enough with the entourage effect to really speak on it, but as a rule of thumb, Effects>potency>Everything else. I dont really care about how weed tastes, or smells. I like a good taste and LOVE the pineapple garbage funk I get from Pineapple Fields, but its the high that has me running a gaggle of seedlings for selection and seed expansion. So in other words, terps arent necessarily my thing. But thats just me.
 
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Dogg1

Member
We share thoughts on environmental factors impacting genetic expression. All goes down to do a little homework before you plant the seed I think... Thanks for chiming in. I appreciate everything
 
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Frankindank

Member
I occasionally dim slightly based on how heavy into fade they are and where I need to get to day wise. But always I like to cut my photoperiod to 10/14 the last week+. Probably a similar reduction in DLI to dimming.
 
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Delps8

Well-Known Member
Dogg1 said:
Hello all, I'm interested to hear it here, I like to dim my SP3000 to 25% last 5-7 days, seems to stack well and resin is always full. I will do this after the advertised flowering time for the plant, kinda hanging out and ripening for up to a week. ANY THOUGHTS?, {crazy, waste of time, nice, pointless}

.02$ COBs seem to benefit from this over SMD panels...(now I got your attention;))
Click to expand...
Light is the only way that cannabis plants can make food. If you reduce light levels, the rate of photosynthesis drops which will tend to slow growth.

Crop yield (flower mass) and secondary metabolite production are a function of growth. The old formula for yield used power draw (watts from the wall) with the assumption that HPS lamps were used. Using LED's, it's a function of mols (PAR). More light, up to the light saturation point, results in a larger crop with higher crop quality (ratio of flower to above ground mass).

Having said that, the comment by @Isawthelight is very valid in the value of reducing PPFD to drop canopy temperature since elevated canopy temps decrease the level of secondary metabolites (long discussion that I've ranted about in other threads here on RIU).

And, yeh, the SP 3000 is a nice light, well the older model, that is. I've used one for a few grows and it did a good job.
 
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Frogglet Legs

Well-Known Member
Last 2 weeks I add uvb 30 mins a day, the last week i turn lights down around 10-15% and 11/13 off also will try to dry out pots abit but not excessively dry at chop, do I think this helps yes big time having past grows with none of the above methods (never compared clones but am sold, its all not much effort)
 
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Dogg1

Member
Delps8 said:
Light is the only way that cannabis plants can make food. If you reduce light levels, the rate of photosynthesis drops which will tend to slow growth.

Crop yield (flower mass) and secondary metabolite production are a function of growth. The old formula for yield used power draw (watts from the wall) with the assumption that HPS lamps were used. Using LED's, it's a function of mols (PAR). More light, up to the light saturation point, results in a larger crop with higher crop quality (ratio of flower to above ground mass).
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Just so we're clear, I'm not going for larger flower mass, I'm trying this more or less as an exercise in in preserving terpenes and volatile oil qualities of the plant. On already hot days I dim my units keeping the temperature low
Frogglet Legs said:
Last 2 weeks I add uvb 30 mins a day, the last week i turn lights down around 10-15% and 11/13 off also will try to dry out pots abit but not excessively dry at chop, do I think this helps yes big time having past grows with none of the above methods (never compared clones but am sold, its all not much effort)
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I ran a California light works system in a 4x4 tent for about a year and a half, supplemental UVB was included in the lamps at the time. Definitely some of the oiliest and stickiest of the chronics that I've turned out.
 
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Frogglet Legs

Well-Known Member
Dogg1 said:
Just so we're clear, I'm not going for larger flower mass, I'm trying this more or less as an exercise in in preserving terpenes and volatile oil qualities of the plant. On already hot days I dim my units keeping the temperature low

I ran a California light works system in a 4x4 tent for about a year and a half, supplemental UVB was included in the lamps at the time. Definitely some of the oiliest and stickiest of the chronics that I've turned out.
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Yeah I have 1 tent with and 4 without uvb I can notice the difference for sure, I think these things defo help preserve/improve terpenes but i think drying/curing properly is key also
 
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Delps8

Well-Known Member
Dogg1 said:
Just so we're clear, I'm not going for larger flower mass, I'm trying this more or less as an exercise in in preserving terpenes and volatile oil qualities of the plant. On already hot days I dim my units keeping the temperature low
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I understand the goal and I believe that your approach is the right way to go.

To stop the loss of secondary metabolites, we've got to keep our temps down. The magic number, according to Mitch Westmoreland, PhD candidate under Bruce Bugbee, is 78°. In his 202o video on "hemp" he mentions that secondary metabolites were dramatically reduced when canopy temp went over 78°. I couldn't find any other mention of that in the research and didn't hear a peep about it till early this year when Bugbee opened the kimono a bid (made you wince, eh!) and talked about temperature being extremely important for cannabis growing.

A few months after that, Westmoreland came out with details of some of the research that he's done for his thesis and he states is clearly (78° but could be strain dependent) and then lays it out very clearly - run temps up to 85° through veg and early flower. This will maximize plant size and morphology. Once the plant stops growing and starts developing flowers in earnest, drop your temp to 78'ish. With vegetative growth having stopped, the plant will use photons for flower production but do what you can to get temps down to minimize loss of secondary metabolites.

When I started growing, I read or watched everything I could get my hands on re. grow lighting. The first light I bought was the SP 3000 but replaced those with a Growcraft 330watt veg light and a 330 watt flower light. Yields were superb, due to a lot of factors, one of which was that ambient temps in the tent were in the low to mid-80's. But weed from the dispensary had more kick to it. I didn't mind the tradeoff because, properly tended, a 2' x 4' tend will yield well over a pound per grow so I had "flower to burn".

But it stuck in my craw that the quality wasn't there and it was just a few months ago that Wesmoreland laid it out so clearly. I"m retiring my Growcraft flower light and can't decide between the Spider SE 4500 and the G4500. I'll be able to run the light, whichever one I pick, at 18"± and still get 1kµmol on the canopy but, because of the increase hang height, I should be able to keep the temps down.

In line with your strategy, I'l keep raising the light until the flower tops are <=78°. I think that will result in the best of both worlds - lotsa weed and very high quality.
 
D

Dogg1

Member
Delps8 said:
I understand the goal and I believe that your approach is the right way to go.

To stop the loss of secondary metabolites, we've got to keep our temps down. The magic number, according to Mitch Westmoreland, PhD candidate under Bruce Bugbee, is 78°. In his 202o video on "hemp" he mentions that secondary metabolites were dramatically reduced when canopy temp went over 78°. I couldn't find any other mention of that in the research and didn't hear a peep about it till early this year when Bugbee opened the kimono a bid (made you wince, eh!) and talked about temperature being extremely important for cannabis growing.

A few months after that, Westmoreland came out with details of some of the research that he's done for his thesis and he states is clearly (78° but could be strain dependent) and then lays it out very clearly - run temps up to 85° through veg and early flower. This will maximize plant size and morphology. Once the plant stops growing and starts developing flowers in earnest, drop your temp to 78'ish. With vegetative growth having stopped, the plant will use photons for flower production but do what you can to get temps down to minimize loss of secondary metabolites.

When I started growing, I read or watched everything I could get my hands on re. grow lighting. The first light I bought was the SP 3000 but replaced those with a Growcraft 330watt veg light and a 330 watt flower light. Yields were superb, due to a lot of factors, one of which was that ambient temps in the tent were in the low to mid-80's. But weed from the dispensary had more kick to it. I didn't mind the tradeoff because, properly tended, a 2' x 4' tend will yield well over a pound per grow so I had "flower to burn".

But it stuck in my craw that the quality wasn't there and it was just a few months ago that Wesmoreland laid it out so clearly. I"m retiring my Growcraft flower light and can't decide between the Spider SE 4500 and the G4500. I'll be able to run the light, whichever one I pick, at 18"± and still get 1kµmol on the canopy but, because of the increase hang height, I should be able to keep the temps down.

In line with your strategy, I'l keep raising the light until the flower tops are <=78°. I think that will result in the best of both worlds - lotsa weed and very high quality.
Click to expand...
Thank goodness for Mr. Bugbee. There's and outstanding video put out by Coco for cannabis. Running lights in arrays. They focus on the sp3000 from Mars hydro. My 4x4 is set up to mimic those test results and everything's been amazing. You might want to watch the video before you buya light it covers a lot of information on not just the Mars lights, but how light move around intents.
 
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Dogg1

Member
Cool thread guys thanks for chiming in. I took down the dimmed garden. Looking rad dimmed or not! I hope everyone enjoys a cool rip of their fav on this hot day, CHEERS!
 
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