Grow Light Hotspots and Light Uniformity 

+Jeb Gardener They have a very beautiful form that is pleasing to the eye. Plants seem to be loving them too, more importantly ;)

+Fumidor Unicorn grower! That's tickled me. I should tell my local hydro store guy how lucky he is to have this one horned winged beast as a customer. Thanks for the awesome feedback! :)

@@Just4Growers Hi, do you think I could eliminate the hotspot in the middle by adding a garden shade cloth, so the light will give off a single uniform ppfd number across the whole board?

Firstly, this is a really interesting and insightful comment so thank you for taking the time to share. I love CMH and DE-CMH and enjoy great results from them. (I still use CMH, DE-CMH in winter.) Nothing beats my 315W 4K CMH (incidentally, with a CRI of 95 !) for vegging up robust and vigorous plants, especially during the cooler months. However, The Color Rendering Index (CRI), is a tad anthropocentric for true plant talk. While being an important metric for assessing how accurately a light source displays the colors of various objects in comparison to a natural light source like sunlight, its relevance in the context of horticultural lighting is relatively low compared to other metrics that are more critical to plant growth (but I appreciate the general heuristic of sunlight being the gold standard for our noble indoor endeavors.) By the way, Nichia make extremely high CRI diodes (their ‘Optisolis’ range scores close to 98) but they’re more likely used in high-end designer clothing retail outlets rather than indoor horticulture. The minimum distance between a DE-CMH lamp and canopy is determined by lamp output and reflector design while environmental factors can round these figures up and down. A double-parabolic like Adjustawings can’t be beaten for close proximity placement. I would be very interested to know the L90 of the Fifth generation of OSLON® Square Hyper Red LEDs by OSRAM. They quote a Q90 of 100,000+ hours but not the same thing. Once again, worth noting the L in L90 stands for lumens, another anthropocentric metric, but what can you do? :) Big indoor light loving heavy fruiting plants? DE-CMH + DE-HPS for the win. Unless you like lollipopping. lol indeed. Enough of my rambling, thanks again for refreshing the lighting conversation!

+sum CLINT Good to hear. As you are generous enough to comment I imagine that not only you but those around you all benefit from your garden's productivity. That I might have been helpful to you in the pursuit of your gardening goals is a gladdening notion indeed amigo. Thanks for sharing! Peace ~E

Everest Fernandez best educational videos on RU-vid. Thanks for sharing your time and knowledge

+Crustcheese Hey amigo, very happy to see you and thanks for chiming in. I will certainly reach out to Gene and I love Growmau5's stuff - always stop what I'm doing when a notification comes in from him! You're gonna love a video I've got in the works - where I look in more detail at the diodes that are used in some of the fixtures I'm using, power consumption, output, efficiency and, of course, sharing my experiences growing with them for a few months. What's really surprised me so far is the different hanging distances that various fixtures require. Some 6", others 3 feet - and broadly comparable wattages. Also - there's how hard the diodes are being driven, the form factor, the quality of the power inputs and heat syncs - this is going to be quite a journey isn't it? :)))) thanks again - peace and happy growing, Everest.

and the journey has just begun :) i have so far build 3 generations of LED grow lights and i could probably build a new version with improved hardware once a moth, the technology is amazing and growing so fast. i cant wait what your next videos and the next years of LED development have in store for us!

HID (particularly CMH) is better for quality due to the superior UV + IR output. And CMH runs at pretty much the exact same efficiency as the top LED fixtures (around the 2.0 umol/W mark). The only advantages that LED’s have on CMH is: 1) less heat (however this might actually be a DISADVANTAGE if you grow in cooler climates) 2) you don’t need to replace a bulb every couple of years, but the much higher initial cost of the LED units means that it will take about 8-10 years before you actually start saving money. And when you factor in the increased quality then it’s really a no brainier (unless you desperately need to reduce temps in you grow space but even then CMH don’t actually put out much heat at all!)

Your request has been received and will be heard!

Thanks! I just added it :) You were too quick off the mark! :)

+Kira Barsmith Great to see your comment Kira - I always appreciate hearing from you and wish you and your garden the very best! :)

Steve A ask at your local hydro store or email growersupport (at) hygro-int (dot) com

+Jason Voorhees You're welcome Jason - I love this stuff! Glad I'm not alone :) peace and happy growing, Everest.

+Jeremiah Wilson Very good question. I need a spectroradiometer to answer that definitively. Maybe I should start a crowdfunding campaign? Lol. What I can tell you is that I understand the lamp has been fine tuned for as close as you can get to optimal for both wattage settings. I will see what data I have from the manufacturer as a starting point ...

+Jeremiah Wilson I double checked with the manufacturer and it is a true 750W DE-HPS lamp. The important thing is the e-ballast has been tuned to give a broad range of high efficiency between 600 and 750 watts.

1-844-202-5666. (Bloom, Colorado) 1-412 523 3363 (Autopot USA, Pittsburgh)

+John Mcneal Thanks John. Your 12 ft high ceiling would just mean the adjustawings would be hung from longer cords and you enjoyed more potential vertical space to play with during the lifecycle. 6 x 600/750W fixtures in your space would work very nicely for light-loving crops.

+Franklin Rand Apogee's SQ-520 is a PAR meter which plugs directly into your computer's USB port and you can download free software on Apogee's website - www.apogeeinstruments.co.uk/downloads/ I logged the measurements manually on a spreadsheet and did the number crunching on that.

You usually get more hotspots under a horizontally mounted HID lamp. What distance between the lamp and your canopy?

lee uk Yes amigo - I have to say, excellent choice. No other fixture (that I am aware of at least) delivers the wonders of DE-HPS more efficiently to the canopy.

+Andrew K. You should know right now that it's ALL going to happen.

+condo_grower1 I can get it around 18" away from the canopy at 750W with a super spreader - probably a touch closer at 600W. Ballast is detachable and comes with a longer cable option if you choose to go the remote route. Nice.

2:13 in, middle table looks like its digging that kelvin your throwing at it! Can I come grow with you Everest?

+Jonathan schadenfreude Hello amigo, hopefully the air movement in the room should be enough to pollinate them flowers and turn them into the hot stuff! I do try and shake em once in a while too.

Everest Fernandez I'm that nut job using my pinkie finger on every flower,that being said my Trinidad scorps are still flowering heading into sept, and well......I'm kinda overwhelmed! But hey man if you ever want vibrant hots I got seeds man!

+Jonathan schadenfreude Seeds. I love seeds.

Everest Fernandez we can do this!

+HighOffThatKush You're welcome amigo.

What species are you growing Mohsen?

Everest Fernandez I'm not starting my growing tend yet I researching first, but I want grow sugar apple and passion fruit in one grow tend and for second one is papaya and guava...Wow Everest asked me a Question I love u man❤️🤘🏽

+Life Aficionado Mr White? Don't you know him?

+Dale Urban thanks Dale.

+bobby blues Hey Bobby, I did everything by the book. (Followed manufacturer's guidelines.) I'll drill down into infrared and what super spreaders actually do - particularly, why they're very handy for light-loving sub tropical species - especially heat sensitive species native to higher altitudes. Now that we have DE HPS, I'd definitely try them in double parabolic reflectors with super spreaders. You can actually get to 45 cm (17.7 inches) with a 750W DE HPS and super spreader. Can't wait to show you all the data. And we will let the plants do the talking too of course! :)

your the man! obviously the lower the light the better the intensity (even though the par readings were all above 500 at 2ft tall) but the less spread.....why did you not choose parabolic reflectors? are the adjustas less problimatic heat wise then the aircooled fixtures ?

What distance is there between the lamp and your canopy? If it's between 18 and 30" then you're good.

I am running a 630 de in the hood and it is hanging at 18 inches. So the visible shadow in the center of the canopy normal?

I’m setting up a DE630 CMH tonight in a Defender wing so will feedback. No, I don’t think it’s normal. But in any case, we will get to the bottom of it!

Fantastic. Wish i could show you a pic. I have read in forums that people have taken the super spreader off because of this. I know plants see light differently than we do so maby they dont "see" the shadow. The 630 has a horable hot spot. I bought the adjust a wing and spreader because of your vid. Im excited your running a 630 cmh in it now. You have the tools to find the truth. Keep up the good work.

Any feedback? Here is a link to a thread I created on a forum with a pic of my canopy and the afore mentioned shadow. www.rollitup.org/t/grand-master-level-training.959611/

Yes - it's in the description, or click right here: goo.gl/qbKmqw

Thanks, it was in the drop down after all. Sorry about that!

+Sarah Dunn All good amigo, I'd be interesting to find out how you got on with the lighting planner tool. I think it's really handy.

+Chwyn right here amigo. Or were you asking me personally? :)

I was just wondering if you took classes on horticulture or something. You know some pretty advanced stuff.

+Chwyn Learning is my life. I came to horticulture through a non-traditional route. Now it's pretty much all I think about most days, afternoons, evenings and nights. :)

+juicyjumbler Certainly not! Love me some LEC action :)

i'm still amazed at the par on the LEC630, trying to decide what to replace my 2 HPS/MH Magnum xxxl's.. Been reading about Spectrum KingLED's and those AgroLEDs.. with 8ft ceilings, between DE's and LED's I can't come to any conclusion!!