If they are on the perimeter, youre seeing whats impacted by the lowest lighting. Everything else still seems happy. About to go up another 5% tomorrow though so
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Ca++
Well-known member
I remember you talking about placements before. Are they the same family? It seems odd to find such a low limit, but it seems like something I could learn from. I keep seeing good grows around 300w a meter, and I wonder if I'm pushing some of mine a bit hard.If they are on the perimeter, youre seeing whats impacted by the lowest lighting. Everything else still seems happy. About to go up another 5% tomorrow though so
The aces in places thing sure has been helping but its multiple strains. Truffle really needs light, tom ford, raskals fire, and our truffle mintz can be productive with dense morphology from the outside. What weve learned though is that raskal really doesnt stretch outside though, so shell stay inside going forward hah. And tbh regardig your lighting, i believe we got very lucky with our particular spacing and sweet spot where the lights converge. At about 12-18 inches below the lights and the furthest space between them were still seeing 7-900 umol, i knew it would be solid and above 600 but it ended up higher than expected. Under the lights at the canopies current distance were nearing the danger zone like i said before hitting 13-1400, but i may juuuuust barely make it through and kill it if i pay close enough attention. What sucks is between the lights above 10-8ish inches away we see light loss. Really just concerned about photobleaching near the red diodes. Ive seen one or two tops bleach a touch. How hard are you pushing yours? Maybe it is a lot, what would you say your average ppfd is?
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Ca++
Well-known member
I have not measured it with full light. I have 250w per meter above them using LED. Than another 300w of HPS, which is worth about 200 of LED. Then I have 100w of LED from below. It's some pretty big numbers.
One bud really stretched out for a 120w QB, and I have let to get within 120mm perhaps. That single bud must have some astronomical lighting, but it still prays. While looks a bit too vegetative. Well.. lets say a lot too vegetative, but it will trim up
Edit: Multiple strains in a common slab? Something looks off.
One bud really stretched out for a 120w QB, and I have let to get within 120mm perhaps. That single bud must have some astronomical lighting, but it still prays. While looks a bit too vegetative. Well.. lets say a lot too vegetative, but it will trim up
Edit: Multiple strains in a common slab? Something looks off.
Curious what your true light intensity is in the most intense spot, it sounds complicated. As for the multiple strains in a single slab, weve done that a lot. We've done it thousands of times. I used to be religious about just one strain in entire trays and especially slabs years ago. It truly makes no difference if you irrigate frequently enough. Some strains obviously drink more than others, which has caused minor surprises but nothing crazy. But yeah, its no biggie.I have not measured it with full light. I have 250w per meter above them using LED. Than another 300w of HPS, which is worth about 200 of LED. Then I have 100w of LED from below. It's some pretty big numbers.
One bud really stretched out for a 120w QB, and I have let to get within 120mm perhaps. That single bud must have some astronomical lighting, but it still prays. While looks a bit too vegetative. Well.. lets say a lot too vegetative, but it will trim up
Edit: Multiple strains in a common slab? Something looks off.
Damn, well thats a lot more intense as an average than my room thats for damn sure. Like i said before i do wish i could run 2 more fixtures. Where you keeping your co2 ppm? How high do you push your vpd towards the end?
weedemart
Well-known member
same here 1200-1400umol/s/m2 which is roughly 50-75 moles/day depending on the light schedule
Ca++
Well-known member
I don't use co2 or calculate vpd. I just want my RH around 60%. Many op's run lower to decrease the chances of mold, but I have been running 7 week plants anyway. The plants are happier, keeping the RH as high as you dare. I feel 60% is about it.
I'm not sure a 45% room would make the core of the big mold prone buds, any drier. Plant health and speed are my preferred option.
My lighting would usually be less, but I'm having a play with the higher numbers. It's really no more than running a 600 per meter, with some decent interlighting. As I did for years. With LED I should probably back down, but here it is
With 4 more QB's below them, pointing up.
I know you know 6s, so you can probably get a good idea from this.
fwimc. I will only talk to the op about my grow, on his thread. It's just too good a thread to sidetrack far.
I have never had light bleaching with LED though. Using ~3000K LM301h and some 660s.
With that high of light intensity you are losing a lot by not giving them co2 enrichment. Youre losing 20+%. Why not run co2 from tank? I also think you could see serious improvement if you keep your rh higher, like 65-70% at the beginning of flower and bring it down closer to 50% toward the end. Both a yield and a quality increase id bet. Temps ranging from 80 down to 74 towards the end. This is my goal anyway. It yields the best quality and returns. Even in a 7 week cycle i think you'll notice.
Weve had a few tops bleach, nothing like under hps, but subtle evidence on the tops that stayed upright and very close in past runs. The ones nearest a red diode go figure hah.
1500 at what distance?
Ca++
Well-known member
I have only seen one person (sshz) get a higher yield than me, and he doesn't use co2. I don't believe releasing captured greenhouse gas to be a good idea. I just tend to bite my tongue. My electricity supplier is green energy only (so they claim) so my growing is actually carbon capture. Not emissions. I'm happy with that position.
I would consider a burner in cooler weather, as I have gas powered heating anyway. It seems I would have to make my own though. Commercial kit is too big, and commercial prices.
60% is the end of flower. I will let it run higher earlier. It's down to 60 to avoid mold, but plants are happier higher.
I don't really have the control to separate Temp from RH. I just exhaust for negative pressure mainly. With a nod to RH, but you can't have everything. I have humidifiers and dehumidifiers, heaters and aircon. I'm just not using it though. What I'm actually lacking, is customers I want to deal with. So I'm in an ever decreasing circle, and starting to think about other opportunities. I'm getting a bit old to be getting busted, and loosing my house, as ill gotten gains tax. So while quality matters, the output really doesn't.
weedemart
Well-known member
I share your position on CO2, quite ironic to inject CO2 when governments pay to get rid of it. And it doesnt not really matter below 1000 umol. can simply run at atmospheric co2 level with good air change and hepa filter.
Have you surpassed 100g per sq/ft? If so, id like to see that. Co2 is a cardinal parameter, it is directly related to the success of many crops in agriculture. But hey, to each their own. I used to go no co2 up until the past 4 years or so. The difference is dramatic. Have you tried it in your space? Fairly inexpensive experiment and you could find out for yourself in a short 7 weeks. Dont stymie your own success over past expectations is something i have to tell myself. Nobody ever improved anything by stating “if it aint broke dont fix it”. Youre a well informed person who i respect, i wouldnt stress this so hard if i didnt think it would be a big deal. You have great suggestions and are an asset on this forum, this is a solid suggestion for you i promise.
As for the RH, have you brought it lower? I find way more quality when i bring it down, yield may slightly decrease but there is much more desirable morphology and way more ice. At 60% rh im not super worried about mold/botrytis until were really above 65%rh. Thats when water activity allows for rapid mold growth. I dont personally bring the rh to 50% in the last couple weeks because of fungal issues, its really about the quality difference.
This is false, yield is measurably higher above 600 umol when you enrich with 1200 ppm co2. Before that its not as necessary, but honestly giving light above 600 umol WITHOUT co2 enrichment is wasteful according to bugbees studies in chambers. Im about to start round 3 of their course, once i have access to the modules again ill share more on this topic.
weedemart
Well-known member
how can it be wastefull when outdoor it get up to 2000 umol at 400 ppm co2?
Cannabis is a C3 plant. the most benefit from co2 enrichement are from 400-800 ppm.in theory 35% photosynthesis gain , if everything is optimal but its never close to optimal in most setups. You need very high temps and adequate vpd in co2 sealed setups, and this high temps play against quality.And the 35% gain minus all the hvac to produce this gain become maybe 10-15%.
what you dont want tho, is co2 below atmospheric level(400ppm)
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Outdoor does not equal what we are capable of indoors at all. The reference is near pointless. Listen to the video for now. Those are the words of a horticulture expert who studied this in depth. Again, once back in the course, ill share more of their results/experiment specifics. Although its pretty simple, they have chambers with precise umol and co2 enrichment parameters they compare. Some with no enrichment and umols at 600/800/1000 and then chambers with co2 enrichment at all those same level of lighting and the yield goes way up. Those arent precise numbers just giving you an idea of what i remember. It made me feel silly for never enriching with co2 for decades. And you are correct about co2 dropping too low, in greenhouses even with ventilation they supplement co2 because otherwise the plants “mine the air” so rapidly that it drops. Those who enrich further see yield increases, especially with cannabis. Also not sure where you got that chart but it doesnt match some of the ones ive seen. Ill have to look.
weedemart
Well-known member
I know that it increases harvests but to benefit from it you need intense lighting, an ideal environment and your HVAC bill will increase considerably, not to mention the cost of the CO2 injected. When you play with the extremes that's where the problems arise and very often it's not worth it. It seems like a big 35% on the harvests but the effort and the cost to get there greatly reduces its relevance.
As your chart says, high co2 need high temps, as the air temps increase, it can hold more vapor and it create more unstable environnement, more loads on the hvac and bigger risk for disease/pest.For example in your room the optimal temps would be 30C , it will create huge stress on the rootzone, especially in rockwool ebbflow,as the optimal rootzone temps is closer to 20C.A good compromise is 25C and it's in line with average co2.
Not to mention the other points; your environment will perhaps favor high production but the quality of the product will be affected. It depends on the goal. I think even if you lose on yield you can gain on quality.
And finally as an hvac guy, there a magic number in climate controle and its 21C. theres a lot of reason for this but think about the outdoor temperature between season and the temperature difference it create between outdoor environnement and your room. Your temperature difference will be much lower on average , in the year, with 21C than 30C and your pocket and your hvac will thanks you.
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weedemart
Well-known member
Just to make things in perspective, at 80f 60%hr which is rougly the same vpd as 90f 70%hr, so ''equal'' vpd
you have 11 btu/lb of air enthalpy difference, which is significant on a hvac system.
on the right you can see the humidity ratio, air hold almost 50% more vapor at 30C than 25C , which mean more deshumidification too.
As you can see theres a cost to co2 enrichment , and its not only the gas, you need to increase the load on hvac by 50% or more and its not a linear correlation , its exponential.
you have 11 btu/lb of air enthalpy difference, which is significant on a hvac system.
on the right you can see the humidity ratio, air hold almost 50% more vapor at 30C than 25C , which mean more deshumidification too.
As you can see theres a cost to co2 enrichment , and its not only the gas, you need to increase the load on hvac by 50% or more and its not a linear correlation , its exponential.
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