Thanks!
This is their 12th day in the tent after coming out of the dixie cups..
Short and bushy? Can light get in there?
- Thread starter Prodigus
- Start date
This is their 12th day in the tent after coming out of the dixie cups..
I wouldn't mind running 24/7. They've been running in the tent on that 18/6 timing and have only ran 41.8 kWh according to my surge protectors statistics it gives me. I guess LED's don't use as much electric as the old bulbs I used to use.. LOL
Those are beautiful!
Yea, my temp is running right at 79-81F so not sure how well that's gonna work out. I haven't maxed the light out yet either though. I think I have it running at about 80% right now. Should I go full blast on these Autos from very beginning like this?
PURPLEB3RRYKUSH
Well-Known Member
Full blast at beginning of flower
PURPLEB3RRYKUSH
Well-Known Member
Try get them to handle 1000 par without bleaching probs need co2
PURPLEB3RRYKUSH
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My temps are average 23c day. 19c at night time even with lights on
PURPLEB3RRYKUSH
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Noticed buds lot denser since I dropped temps and they go purple
PURPLEB3RRYKUSH
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I'm running high co2
PURPLEB3RRYKUSH
Well-Known Member
I get bleach around 1250 par
"full blast" - the more light you give your plant, the greater your yield assuming that light is the constraining factor. That means that the other parts of your grow need to be dress right dress before you can max out your light levels.
In the research lab, cannabis will thrive at light levels >2000µmol. I don't know how they did it but I've seen research that goes up to 1800µmol and Mitch Westmoreland did a YT video where he shares his PhD research with light levels >2000µmol.
So the plant can do it, the question is how to high to go and how to get there.
I've attached a graphic that lays out the components of a grow environment. Per above, the amount of light a cannabis plant can is dependent on the other parameters. I've seen grows that couldn't handle more than 400µmol. In both cases, growers hadn't done a very good job watering their plants and the soil was rock hard in some places. On the other hand, for my grows, which is about as optimized as I'm able to get it, I've run my autos at 1100µmol± and, for my most recent grow, was at 1150µmol.
The most light a plant can handle is called the "light saturation point" ("LSP"). For a seedling, you're going to hit the LSP at, maybe, 400µmol. I've pasted in the light data from my most recent grow. It's pretty standard for how I feed my plants. In the comments, I list the lights that were used. If your grow is in good shape, there's no particular reason why a grow can't use those light levels, or higher. I add "or higher" because the LSP depends on all of the parts of the grow environment, including the genetics.
If you want to keep your plants at the LSP, you can save a lot of time and aggravation by using a PAR meter or a light meter. I would not recommend using a mobile phone + software. If you've got the $$, I'd got with an Apogee but an Apogee is $600±. There are PAR meters on Amazon that are quite inexpensive but they probably use a sensor that cannot read above 660nm. Yes, they advertise that they can read to 700nm but I have my doubts. All told, if you don't want to drop $600 on an Apogee, a Uni-T lux meter + the document I've written (attached) is, in practical terms, as useful as a PAR meter.
Without a doubt, you can run "high light" (1kµmol±) without a light meter. The advantage of using a meter is that it allows you to set your light levels at an "appropriate" level and then, after watching your plants to see how they react, you can increase or decrease the light levels.
The numbers that I've provided are nothing magical but you can use them as a guide. If your grow can handle more light, add 100, for example, to the value that I used, set your light to that PPFD, and then see how your plant reacts. If you're not seeing symptoms of too much light, add 50 or 100µmol. Lather, rinse, repeat.
A big lesson that I learned last week, while watching the Westmoreland video, is that while light is the main ingredient for high yield, temperature is key to preserving secondary metabolites. I've generally grown my plants at 80-83 (or so). Westmoreland made it very clear that temps should be in the 70's once you hit flower so it's 80-85 in veg, for optimal growth, and then drop the temps into the 70's to preserve terpenes and cannabinoids.
Lots of info there and not a direct answer to your question but this is not a simple topic. Hmm…lemme restate that. Lighting you grow can be really simple and you'll get a good harvest. Cannabis is like that. On the other hand, cannabis
This table is from the cited paper. It's an excellent read and it was the first research paper I read that a directly addressed the question of how light impacts yield. Simply put, for every 50µmol increase in PPFD, yield increased by about 4%. Going from 800µmol to 1000µmol resulted in almost 20% more weed. To some growers, that no big deal and I get that because, even at 800µmol, you can grow a lot of weed. But at 1kµmol, you can get quite a bit more.
If you're running CO2 and limited to 1250, I'd wonder what's going on with your grow OR what's going on with your meter. What's your CO2 PPM and how are you measuring PPFD?
I'd love to run CO2 but I'm really space-limited.
PURPLEB3RRYKUSH
Well-Known Member
Autoflowers only handle so much photos can take 1500If you're running CO2 and limited to 1250, I'd wonder what's going on with your grow OR what's going on with your meter. What's your CO2 PPM and how are you measuring PPFD?
I'd love to run CO2 but I'm really space-limited.
PURPLEB3RRYKUSH
Well-Known Member
Day 84 I get over 2 oz a square foot
