Lighting Did the deed. New Par meter on its way.

[Death The Cultivator]

Just a teaser, laid out a grid and tried the lights and meter. Initial results ~850 mmol/m2 @ 24" in dead center of 2x4, goes down to >700 @ 6" from the corners. I'll do a more detailed map later, but at this rate, with 20/4 lights, I can get ~60 DLI with all bulbs on @ 24", or I can back off on DLI by increasing distance or unscrewing bulbs. 60 DLI is likely more than my skills can handle - it is near the top of the tolerance range with anything less than perfect management of other factors. I will likely shoot for 45-50 DLI during my next grow.

Happy lighting peeps. More later.

That's promising! I'd be interested to see how penetration looks in a dense canopy. Thanks for keeping me posted

 

[derek420colorado]

I just ordered this one today. @pop22 uses it pretty stoked to finally be able to accurately calculate DLI

 

[Olderfart]

I just ordered this one today. @pop22 uses it pretty stoked to finally be able to accurately calculate DLIView attachment 1303153

Looks good. Have fun with it.

 

[Olderfart]

That's promising! I'd be interested to see how penetration looks in a dense canopy. Thanks for keeping me posted

Well, by this time next year, you will have seen what it looks like.

My plan will be to use the lights at full power, but raise them until the ppfd at the canopy top will produce the DLI that I want. l think more light from further away makes for better penetration. Kinda like the sun works.

 

[Olderfart]

Ok lightsters, here she is, a par map for my screwins in my 2x4.

I adjusted height to get ~700 ppfd in the central blocks. This would give me a DLI of ~50 with 20/4 lighting, which is likely as high as would be a good idea for me. I got 700 ppfd in the central blocks with the lights at 48 inches from the meter sensor. Here is the map for the entire 2x4:

Sorry about the weird texture, the image is a screenshot from another computer.

Bottom line is that these screwins will deliver more light to plants in my 2x4 than I can manage by a significant margin. Keep in mind that this is at 48". With delivery of full DLI from this far away from the canopy, penetration will be excellent. Light distribution is as even or more so compared to any 2x4 lighting I have seen par maps for.

During a grow, I will have to dim the array by unscrewing bulbs once I lose the 48 inches clearance, but I have lots of height in the growdrobe, so that will still work fine.

The power of the lights is a bit surprising, and likely the reason that I overdid it during my first couple grows. Now that the par meter is in hand, I should be able to keep things dialed better.

Work for you @damien50?

 

[Death The Cultivator]

Ok lightsters, here she is, a par map for my screwins in my 2x4.

I adjusted height to get ~700 ppfd in the central blocks. This would give me a DLI of ~50 with 20/4 lighting, which is likely as high as would be a good idea for me. I got 700 ppfd in the central blocks with the lights at 48 inches from the meter sensor. Here is the map for the entire 2x4:

View attachment 1303751

Sorry about the weird texture, the image is a screenshot from another computer.

Bottom line is that these screwins will deliver more light to plants in my 2x4 than I can manage by a significant margin. Keep in mind that this is at 48". With delivery of full DLI from this far away from the canopy, penetration will be excellent. Light distribution is as even or more so compared to any 2x4 lighting I have seen par maps for.

During a grow, I will have to dim the array by unscrewing bulbs once I lose the 48 inches clearance, but I have lots of height in the growdrobe, so that will still work fine.

The power of the lights is a bit surprising, and likely the reason that I overdid it during my first couple grows. Now that the par meter is in hand, I should be able to keep things dialed better.

Fantastic! I've been saying it's integral tool for growers, glad someone is making a more cost effective tool. Lux meters are trash for measurements related to Horticulture.

Could you measure PPFD drop off for every 6-12"?

 

[Olderfart]

Fantastic! I've been saying it's integral tool for growers, glad someone is making a more cost effective tool. Lux meters are trash for measurements related to Horticulture.

Could you measure PPFD drop off for every 6-12"?

I could indeed, and will get back to you. I will just do the central blocks for now.

In any case, in this setup with the light array spread out so widely, the dropoff will be less than the inverse square rule suggests. The role of wall reflections in this small growdrobe is huge. Closing the second growdrobe door made a major difference in all readings, usually greater than 100 mmols/ms. Put another way, a partially opened door made more difference in light level than the difference between central blocks and corner ones. I expected this to a degree, but find the strength of the effect surprising. More later.

 

[Olderfart]

@damien50, here is the information you asked for. Height in feet on the left, center ppfd on right:

The effects of wall reflection show up nicely. The inverse square rule suggests that light level at 4 feet should be 1/4 that at two feet, i.e. about ~270mmol/m2s. In fact, it is almost three times the light level predicted by the inverse square rule. Similarly the rule predicts 241mmol/m2s at 5 feet given the 966 at 2.5 feet. The actual light at 5 feet is 569, not quite twice what is predicted.

One could also fuss with light delivered at different depths in a canopy, and compare changes in the corners rather than the center, but I am off for a walk with the hound instead.

 

[Bob's Auto's]

Hey @Olderfart. Would you mind if I sent you 3 of my cobs? Just out of curiosity...Would like to know what the PAR value is on this cheap Chinese fabricated electronics.

 

[Death The Cultivator]

@damien50, here is the information you asked for. Height in feet on the left, center ppfd on right:

View attachment 1304326

The effects of wall reflection show up nicely. The inverse square rule suggests that light level at 4 feet should be 1/4 that at two feet, i.e. about ~270mmol/m2s. In fact, it is almost three times the light level predicted by the inverse square rule. Similarly the rule predicts 241mmol/m2s at 5 feet given the 966 at 2.5 feet. The actual light at 5 feet is 569, not quite twice what is predicted.

One could also fuss with light delivered at different depths in a canopy, and compare changes in the corners rather than the center, but I am off for a walk with the hound instead.

That's not bad at all! Not that I ever doubted screw in LEDs but whoa 5ft away and 600ppfd, you built a damn strong high bay light lol. Good enough for me, thanks for keeping me posted.