UMol lighting chart

[Stone420]

Greetings:

I am setting up a new 2x4 with a HLG 320 XL QB light w/ adjustable dimmer power supply. It can go from 36 watts low to 349 watts maxed...these are at the wall readings.

Can anyone link a chart showing how many uMols to set for seedlings based on a 18 hour veg day? I know I'll increase uMol as they grow, so any chart I can see and print will be helpful. I have a PAR sensor, so I need to know how to find settings for optimal growth in various stages of growth.

THANKS!!

 

[FelipeBlu]

I don’t have a chart, but from my experience, a PPFD of 250 umoles is a reasonable place to start with seedlings that have at least 3 sets of true leaves. Prior to that, even a 26W CFL (2” distance) would be adequate.

 

[Old Salt]

@Emilya has posted Lux figures she's using in her current grow. There is a conversion factor that can be used. It's near 67 Lux/PAR. I think she has the exact value listed.

 

[Elevated Lighting Company]

Greetings:

I am setting up a new 2x4 with a HLG 320 XL QB light w/ adjustable dimmer power supply. It can go from 36 watts low to 349 watts maxed...these are at the wall readings.

Can anyone link a chart showing how many uMols to set for seedlings based on a 18 hour veg day? I know I'll increase uMol as they grow, so any chart I can see and print will be helpful. I have a PAR sensor, so I need to know how to find settings for optimal growth in various stages of growth.

THANKS!!

Your best option is to do what Old Salt mentioned above. Get a LUX meter or download a reasonable one to your phone to measure then convert. It will give you a rough idea where your PPFD is at.

Also note hanging height will impact this as well.

 

[Emilya Green]

Here is what I found as I was publishing the info about my new lights:

We know that clones and seedlings need between 5000-7000 LUX for optimum growth. We know that in Veg the plants can take a lot more light and depending on how big they are, 15k-50K LUX is appropriate for optimum growth. In flower we can hit them with even more light, and 45K-65K LUX will do just fine. Some plants can stand up to 75K LUX in flower, but you are in risky territory of bleaching up here, and generally anything over 85K would be lethal.

With my lights the conversion factor to move to PAR from my lux numbers was 66.8, or 67 as was mentioned above. So converting the above to PAR, we get for seedlings, 75-100 PAR, 225-750 PAR for veg and 670-975 PAR for flower.

 

[Mars Hydro]

Hi Stone420, welcome to
Usually during veg, when you have 200umol , plants will start to grow, they will grow very nice if the ppfd reaches around 400~600umol.
During flower: from 500umol, plants will flower, but they will flower really good around 700~900 umol. Data over 900~1000~2000 actually have not too much difference for plants' growing, so no need to look for too high par value. Hope this helps!