Week4@inCharge
Well-Known Member
lower it till you get at least 350
Led lights= More mg?
- Thread starter Willie Nillly
- Start date
Willie Nillly
Member
Dr
Dropped the light to 16" turned up to max. reading 456
Willie Nillly
Member
At this point not sure if it's the phone or the light. Dropped the light to 16 turned up to max only reads 450
Week4@inCharge
Well-Known Member
Willie Nillly
Member
Got a good phone/ now 350@24"40%
Week4@inCharge
Well-Known Member
All right ... That's more like it.. awesome.
Willie Nillly
Member
When I get into last 2 weeks of veg what is a good number to shoot for
Week4@inCharge
Well-Known Member
Some are really anal about this kind of stuff, so you'll get a lot of different responses about this. And it's dependent if your growing photos or autos too .. just a lot of variables. If your growing photos push it as far as you can, maybe to 600 or so. There's some good articles out there that can guide you. Some growers use C02 and that changes the dynamics of these numbers too, for regular growers like us I'm thinking 600 or so is a good number to get too. (gonna see if I can find something for you to read up on) just learn to read your plants, they'll tell you if they want more or less light.
Common PAR Levels for Cannabis
Identifying the ideal PAR levels is quite complex and dependent on a lot of influencing factors. This article provides and overview, recommendations, and signs to detect if your cannabis plant has too much or too little light.
growlightmeter.com
Cannabis will grow between 64µmols and, in ambient CO2, 800-1000µmol. 600µmol will give you a crop but crop quality and yield increase in an almost linear manner so, sure you can grow at 600µmol, but assuming the rest of your grow environment is "co-optimized", you get more and better weed if you turn it up.Some are really anal about this kind of stuff, so you'll get a lot of different responses about this. And it's dependent if your growing photos or autos too .. just a lot of variables. If your growing photos push it as far as you can, maybe to 600 or so. There's some good articles out there that can guide you. Some growers use C02 and that changes the dynamics of these numbers too, for regular growers like us I'm thinking 600 or so is a good number to get too. (gonna see if I can find something for you to read up on) just learn to read your plants, they'll tell you if they want more or less light.
Common PAR Levels for Cannabis
Identifying the ideal PAR levels is quite complex and dependent on a lot of influencing factors. This article provides and overview, recommendations, and signs to detect if your cannabis plant has too much or too little light.
The chart at growlightmeter.com is based on Dominik's opinion. I've tested Photone twice and recommend it only if you can calibrate it. Overall, I believe that growers are much better served to use a Unit-T Bluetooth light meter rather than Photone (unless you can calibrate photons against a known good source).
The issue is not with the code; the complexity is the underlying chip. iOS phones tend to use the same or similar chips over the different model years but Android is very difficult to get right because there are so many different phones. As a software engineer for > 30 years, I understand his pain.
Anyway, while trading email about Photone, I asked about citations to support the data on the chart (there were none) and when I asked why they recommend 45 DLI for autos, the response was because they consider that autos are always in veg so they consider 45mol to the the right value.
Ugh.
There's simply no research out there to substantiate what they recommend. Well, not that I've been able to find and I've spend hundreds of hours reading about cannabis grow lights and grow lighting since I started growing again in early 2021.
Everything I've read and/or videos I've watched indicates that the light saturation point (800-1kµmol, strain dependent) provides the highest crop yield and quality. There's simply no discussion about lower values being the stopping point.
My current grow, 33 days.
One photoperiod Glookie in a 2' x 4' tent, Growcraft X3 at 250 watts. Average PPFD is 839, avg DLI is 72.5, St Dev for PPFD is 49 and 4 for DLI so the canopy is pretty well lighted ("lit"?)
I've got nothing against what the folks at growlightmeter.com are doing. Photone can work well (if you light the idea of putting a $1k phone in a grow tent and if you don't want to use a wand to get "flaps closed" readings) but for $32 you can get a meter of standard level of (in)accuracy that is, for practical purposes, as (in)accurate as my Apogee.
Cannabis loves light//is a light whore. Turn it up to 11 and stand back.
Last edited:
Willie Nillly
Member
I've got a uni t on order. Should get me going in the right direction on that end.
Week4@inCharge
Well-Known Member
There's an interesting bro science video out there that seems to be on point, there's a section there on how to achieve proper height.
Willie Nillly
Member
Had/have a few problems that I've worked on.1- Fan/ even though I had it on 1 it is a pedestal fan. Moved it 6 ft away, no hurricane effects just a gentle breeze. I knew better but...2- the vpd thing/ just got a good dehumidifier... Now it's 53%@77° day 3 and they look way better already. Pulled out around 3 gallons already.
Last watering put in a teaspoon of epsom . On the 2 with issues kind of looks like a little bit of progress?
Last watering put in a teaspoon of epsom . On the 2 with issues kind of looks like a little bit of progress?
Great. I think it will serve you well but…
There's always a "but", eh?
Since light meters read a different part of the light spectrum, you need to convert lumens to PAR. I've attached a document that I wrote that will step you through that.
I use my Apogee almost all the time but I sometime use my Uni-T (which I bought for comparing to my Apogee). Over the 2 years or so that I've had both, the numbers consistently come out good between the two. I use up to four lights over the course of a grow (yeh, I'm into grow lights) and the numbers are bang on.
Willie Nillly
Member
Little bit of a learning curve. 30 years of hps here... Nothing that can't be dealt with. Thanks for your help. I can shurly use it.
Thank you for posting that. It's great to show what things look like when plants get too much light.
It's easy to give your plants too much light. I've done it and it's no big deal because I'm careful with my plants and, if I muck up and turn it up too fast, I'll catch it as soon as I see then taco (also know as "canoeing"). Another symptom is that leaves will rotate around their petiole, their stem. Those photo avoidance actions are quickly resolved by turning down the light. When
I have seen pictures of tissue death and that's not easy to do, to be blunt. My take is that if you're going to push your plants like that, you've got to be careful.
The symptoms portion is on the money. The how to set your light is hinky. If you don't have a meter, go by the manufacturers recommended settings. They tend to be conservative meaning they err on the side of safety.
And, ironically, the overall look of his plants indicates that they could use more light - they're very tall and slender, reduced foliage, and significant internodal space.
Willie Nillly
Member
Attachments
Wow, 30 years, eh? I did one grow in 2017 and then started again in 2021 so my experience is limited.
Some growers have issues when they switch from HPS to LED. I hope your travels have been smooth.
Willie Nillly
Member
Grew my first plant outdoors in 77. Indoor with florescent grow bulbs 81. Mercy vapor gym light in 85. 2/150 hps in 93. You get the picture. A journey the whole time!
That looks like it might be too much of a good thing. The leaves are tacoing but the necrosis and discoloration could be from a nutrient issue.Too much light can be accompanied by too much heat. That drives up VPD which drives up transpiration which drives up nutrient intake. Very no bueno.
Are those pix from your plants now?
One grower (on another site) couldn't get his plants to handle > about 500µmol. It turned out that he had mucked up watering and the bottom part of his soil pots were hygrophobic. He had some leaf damage, as well.
Willie Nillly
Member
And adjusted the light to a proper power and height. Not on stun.