LED Light Types, Kelvin Rating, and Color

OK, due to tight finances, I built my own 200 true watt LED Full Spectrum Grow Panel using 2500K to 3500K for flower 3 to one with 5,000K to 6,500K for veg. The color of the flower LED’s is a warm yellowish color, and the veg lights are kind of a whitish very light blue color. (Side note: my neighbor got on a tall ladder to spy on what I was doing and saw my outside grow shed behind a tall wooden fence. He was thrilled, thank God!!! So much so, he invested in a Mars Reflector 96 Series grow light to supplement my own light. So, don’t depend on tall fences for security!!!).

However, the Mars is really, really blue, red, yellow, and white; so much purplish light you could hardly see after looking at it! Mine is twice the true wattage, but looks more yellowish/white. Now, I have two of my plants under the Mars, and two under mine. They are both growing the same, even though the Mars is perceived brighter and purplish and has less true wattage than mine.

So, why the perceived color difference?
Why is mine with twice the watts growing the same? ( I also built 150W CFL bulb and a 150W LED bulb full spectrum grow lights with the same colors as the LED panel lights for isolation and/or clones in 50 gallon trash cans.)
Will the perceived color difference with my home made LED panel, and isolation grow lights cause me trouble later?

I am ten days into flowering and just wonder if they will continue to grow/flower? Since this is my first indoor grow, I am a little nervous now that I have seen a store bought LED Full Spectrum Grow Light compared with mine.

MG Grows

I’m not entirely sure what you are asking. In an thread from a couple of years ago, I address why some white light in LEDs can be good and why Red and Blue LEDs are more efficient at growing than only or all white LEDs, watt per watt.

Have a read and maybe it will answer some of your questions, or maybe help you clarify your own ideas on the matter and you will come up with new questions, which I’d be happy to answer as you reply here.

happy growing,


Kelvin color ratings is all I know; I have limited brain capacity, so certain concepts are not well understood like NM. Almost every post site that describes LED’s/CFL’s says that 2500 - 3200K are best for flowering 4-1 over 5,000-6,500K for veg. The actual colors are not usually stated by color, but by Kelvin rating. That is why I built my own LED’s in that range. I used the 3520 5 meter strip lights to build it as the picture shows, as yellowish and white.

I hope that clarifies the background behind my questions. Really, the answers to my questions would boil down to:

  1. Should I buy a roll of red and a roll of blue LED’s to augment my grow light?
  2. Should I abandon using Kelvin ratings and just use red/blue colors?
  3. If color is more important than Kelvin ratings, why do the LED sites even use Kelvin?

Since this is my first indoor grow, I want to try to understand as much as possible about lighting in a hot/humid area of the country. I did go back and read your previous posts, but they were color/nm and not Kelvin.
Thanks in advance,

This is just a flag to point to my recent post with clarified questions that I really would like answered so I know what to do from here. Since I am already at the end of week 3 of flowing, I still have time to add actual colors to my Kelvin built grow light. I did read your posting and it was informative, however, I still am confused by Kelvin VS Color?
Thanks for your patience with this Newbie!

[quote=“MGGrows, post:1, topic:5317”]

Lovethegro, your reply did not post except for what looks like computer programming code. I appreciate your willingness to assist me in understanding why all LED’s, Fluorescents, and CFL’s are listed my Kelvin ratings and every site I have gone too also lists lights by Kelvin rating, not NM, for growing. Since I build my own LED’s, I can adjust the lights, if I knew that it would be helpful, as cost is the main issue.

Thank you in advance for your input.

You make me so jealous. My grow is so small and crude compared to yours.

Danfos, wow do pictures lie! My outdoor grow shed came from Lowes, a 2’x4’ OD storage shed on sale for $300. I cut four floor holes in each bottom corner and put charcoal activated sheets in them to block light and bugs. I put standard floor a/c vents to cover the intake holes. Lined the inside with foil insulation (I live in the hottest/most humid state in the country so insulation is a must) and put two 2"X4"s length wise to support the $50 bathroom exhaust fan that runs when the lights are off, the activated charcoal filter and all the lights… Then I mounted a six inch exhaust fan and activated charcoal filter to run when the lights are on. Finally, I painted the plastic floor with flat white plastic spray paint and put locks both inside and out. Instant outdoor grow shed with four plants in a neighborhood totally stealth!

So, the only thing now I have to finalize are the lighting systems. Because I am disabled, I do not have the income to spend a thousand dollars on lights, so I built my own out of LED strips from ebay. I tested each claimed wattage and stuck with the most accurately stated wattage which is Supernight. Not the best, but accurate in their claims so you can adjust accordingly. Supernight does sell blue and red 5050 SMD lights, but do not list the Kelvin or NM rating, just color, watts and amps. I will be more the glad to answer any outdoor grow shed questions you may have accept lighting to which I hope someone will respond to my questions so I can proceed before the flowering stage is over!