Lighting

[BTzGrow]

For 6 cobs you can run cobs at 50W power. With 3 or 4 Cobs you can run them all with 100 w power.
I have example for 3 COB's growlight. 2xCitizen 3500K at 100W power each and 1 Cree 6500K with 70W power (I use Cree because I was still waiting for new Citizen COB's).

Are your numbers here 50watts for each COB on the 6COB unit and 100Watt total for 3-4 COB? My understanding is that the Cree COB chips use approximately 50Watts DC each but the Drivers typically use only about 200Watts AC at the wall outlet, regardless of how many COB's? I don't have experience directly measuring this and I'm looking to confirm AC Watts. I'm wondering is some people are confused by the difference. I could see referring to a LED light fixture by it's total DC Wattage of the combined COB's or other Style of LED, but aren't the gram/watt numbers based on AC Watts?

My second question is with regards to DLI Saturation. My understanding is that Cannabis in Veg Saturates at about 25 Mol/Day and 35 Mol/Day for the final stages of Flower. Additionally my understand with regards to the DLI Saturation is once a grower meets the DLI Saturation in a particular lighting session that the high power lights can be discontinued and just a regular low powered light can remain on to maintain the lighting schedule. Any opinions on this??

Currently I'm running two Black Diamond Perfect Sun Mini's side by side with 8 inches separation covering a 2x2.5 space. At 24" above the SOG I'm getting 600PAR. Since I'm in a 12/12 stretch cycle currently this works out to be ~25Mol/Day. As the transition moves into flower I will start closing the distance so when 2-3 weeks remain I will drop to 18inches which will produce 900PAR and ~35Mol/Day. Does that sound about right?

 

[Mayne]

If you ask growboss, he says to move light away last 2 weeks,.. Heat destroys trics, so why would we put closer when they are most delicate.

Food for thought.

Ive been looking into "getting 2 days outta 1",

The thing with PerfectSun mini, is they are really powerfull, BUT, the closer you get the hotter the leaf temp gets, kinda like holding a magnifing glass in the sun, onto a leaf. SO, the closer you get to the Mini, the hotter the interior of the leaf gets.

U using a real PAR meter?

 

[BTzGrow]

Hi there Mayne buddy. Yes I actually dropped the coin on a Hydrofarm LGBQM Quantum PAR Meter with Micromol Sensor that wasn't working on eBay for $38 and fixed it. I love doing sh*t like that. hehehe!

I'm going to have to do some research on the distance/heat thing idea with the Mini's. I hadn't heard, but then I'm still quite a bit of a Newbie on the subject that Trich's were damaged by heat. Certainly don't want that. My sources to this point are saying that getting the DLI up to 35mol/day produces the nice super frosty nubs we all like.

I'm very happy with my current distance and will slowly move down some, but even at 18-20" I'm pretty sure the heat is going to be very marginal and still producing near the DLI I want to see.

 

[Mayne]

Right on BTz,

Im using the Mini with my 4 cobs, in a 3.5x8 area ( using just half area)

 

[Mayne]

oh, and great find on the PAR meter, hit me up if you find another, lol.

 

[BTzGrow]

oh, and great find on the PAR meter, hit me up if you find another, lol.

If you find one listed as not working let me know and I can check it out. If it has certain problems I might be able to reset.

 

[BTzGrow]

If you ask growboss, he says to move light away last 2 weeks,.. Heat destroys trics, so why would we put closer when they are most delicate.

The thing with PerfectSun mini, is they are really powerfull, BUT, the closer you get the hotter the leaf temp gets, kinda like holding a magnifing glass in the sun, onto a leaf. SO, the closer you get to the Mini, the hotter the interior of the leaf gets.

I'm not so sure you problem was heat as much as light intensity. I will certainly agree the lens magnify the light greatly. @FelipeBlu experienced real issues with his grow using the PS MIni and attributed it to light damage due to intensity rather than heat.

 

[Mayne]

yeap, it seems it dont grow within 24 inches or less. Seedlings at like 48inches, lol..

I have a few 14 day olds, and I just blast them for like 4 hours under the mini, then turn it off, and then they just feed off the 4 cob light rig. Probably hitting my DLI with just that little bit of light. cant imagine it would take much.

 

[BTzGrow]

I'm actually considering using my T5 two bulb fixture with blue bulbs at 6500K for the first month to month and half because I should be able to control and keep very tight node spacing. Of course the first 3-4 weeks will be in my Clone/Seedling Tote I made in a separate thread. That way I can start something while in the last couple of weeks of flowering into harvest and drying in the tent.

My other thought is to move my T5 into the tent and keep it within a couple of inches of the green and turn on the Mini's above 30inches to begin the acclimate the plants to the new spectrum for a week. I'm really going to concentrate on trying to keep very tight nodes spacing on this next grow.

Any suggestions or successful techniques on that would be appreciated for sure.

 

[Mayne]

yeah, just increase the blues i guess. T5 is a good route,.. Mini is a funny light, kickin myself in the ass for buying one to be honest. Now, if you can dim it, its a great light. lol..

You want tight spacing for what reasons? your SOG, Id let them strecht myself. With the mini, best bet would be scrog, and 2 minis, your looking at a good 2.5x2.5 for a good flower. so Id LST the heck outta them, keep the branches as level to eachother as you can so the branches run horizonal, FAST, which then gives you many more branchs from those branches nodes. Im sure you know what Im talking about..

 

[BTzGrow]

I had great success with a nice tight grow during the beginning, and I was using the T5. I feel with the Blue at 6500K that is a perfect early veg light for at least the first month. The major differences I plan to change with the next grow in to start with good nutes much earlier, and start with some really early LST. I didn't start feeding nutes for more than 6 weeks and other than the screen did not LST other than some early Topping above the 5th node during that same 6 weeks. The screen actually didn't get put on until the after almost 60 days. I am looking to do some very interesting early LST to Mainline some manifold branching and also some rather interesting early defoliation to expose areas that are normally shaded. The other thing I will be doing is harvesting a couple of clones after 3-4 weeks to see if I can do a really early sexing reveal. My first clones were very successful at that, just done rather late in the game.