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Ppfd?

Mollisol

Mollisol

New member
I see post after post. People measuring their lights. Checking the intensity all over their tent.

Give them full power. Why make it so complicated?

If your burning your plants? Raise the lights.

I mean shit. Ever grab a hot pan? Don't do that. Wait until it cools or use an oven mitt.
 
My lights, 2 x quantum boards, are running at 35% and at 59" above the coco. I set it up so the seedlings get the right amount of PPFD and it kept the room at temp without the AC running. I also wanted to keep the lights high so I could monitor the babies and adjust and spray 3 or 4 times a day without hitting my head or getting light burn on the back of my neck.

I couldn't do that with much accuracy without measuring it. It helps a lot right through the grow.

Edit. I just use a phone app which is free. Not terribly accurate but you can calibrate it to a known height and PPFD for your light. Still not greatly accurate but good enough to get things going and for adjustments in height and power. Light intensity also ties in with nute strength and environment. Last grow I knew my tallest colas were getting more than 1300 PPFD and the canopy was at around a 1000 PPFD. Without the PPFD meter I couldn't get the spacing of the lights right either, I had them way too close together. With it I have got it right.
 
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My lights aren't in a tent either so I lift them up a bit higher than normal for a bit of a more even spread. Getting the spacing right you need help with that. Last grow I had them spaced at 12" apart. Which was way off. Now at 23" apart which is much more even light down the middle at full power 1000 PPFD at about 28" above the meter. Last grow was over 1300 PPFD down the middle at 30" high and I ran out of ceiling height...duh!
 
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I don't think you're off base Mollisol. I wonder the same thing. Bluey makes a good point. I think the difference is experience. Newbies get caught up in all the gadgets, shortcuts, and stuff that experienced growers do and think they have to mimic that to have a good grow. And some are just more drawn to the technical aspects of things than others. For me, I want to know the why, and then I'll adjust accordingly.
 
golfnrl Thats me! #1 I’m a science geek, #2 I’m a newbie and need to know exactly the conditions until I feel comfortable understanding, then training wheels will come off. But I also understand this is nature (in an indoor, fake environment) and I do let my plants do the talking. I’m trying to give them a comfy home. I’m also an avid vegetable gardener that doesn’t nearly do this for my outdoor garden other than soil health (ph for plant type mainly).
But I get it. Too each their own…this is just me. One day I’ll be cool and it’ll become second nature. But for now, I need understand ever aspect of this art and science. Cheers!
 
Some people concentrate on every detail, some do not. I prefer the KISS method. Sure you can push the tech to get the absolute best. Is that really necessary? It is easy to get caught in the detail trap and now your hobby has turned into work.
 
Why do people make it so hard.............

Download a light meter app for your phone.

Learn what DLI(Daily Light Integral) is.

Doesn't get any simpler than that and provides the correct amount of light to your plant.

The same way you measure nutrients for your plants at their different stages you should be measuring the light you give them. Nutrients are food for the plant. So is light. Dumping 1000ppm solution on a seedling will kill it. So will too much light. Dump that same 1000ppm solution on a mature plant and it'll eat it up like nothing.

DLI will allow you to give the correct range of light energy to your plant at the stage of growth that it's at.

If you need a rough idea you can use this chart but DLI is more accurate and allows you to steer the plant more effectively.

cob lux distance watttage.png
 
I bought a meter to measure mine. Why guess? Some people who disagree with checking light levels spend half the grow checking ph. That's stupid. Oh, you got a spot, check ph. Yellow leaves, ph. Curling, ph. Ph, ph, ph... 3/4 of the advice is here is check ph which in my opinion is a joke. Here's a clue, use a soil with proper buffers and you ain't gotta worry about it. Buy a proper meter, and you ain't guessing ppfd.
 
I use it every watering. So much guess work is eliminated. One of the most used tools in my arsenal.
 

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