I just completed my first grow. Trim is done and cure in underway. I’m trying to go back and understand what factors contributed to my final yield.
I grew (2) plants in a 2x4 tent w/ (1) 600w LED. Final yield was 128.8 gr (4.6 oz). Being my first grow and was only ball parking what my final yells would be. My yield was a lot lower than I expected. I was expecting closer to 10 oz.
Maybe this outcome is normal for what I have but I want to fully understand why. Im thinking a part of it could be my light “efficiency “ but not sure how to calculate (umol/joule). I bought the light back in 2017 and know that a lot of advancements have been made since. My goal is to figure out if I should get a new grow light. I want to get closer to 1 gr/watt.
I attached my grow light specs and parameters in hopes to have someone take a look at it to better understand if my light efficacy is garbage and need to get a better one.
In Chris’ newEr “garden talk” episode from June they say any efficacy below 2.0 umm/joule. How can I calculate this with the attached informatio?




Well PAR is really more important than grow light efficiency when talking about yield. Honestly there are soooo many reasons for why your yield may be lower than expected. What were your CO2 levels? Did you have VPD dialed in? How much PAR was hitting your plants? You don't have to answer those questions here; I just said them to give you examples of what to look at. It would be too long for me to type out all the reasons, but I did do a video with Cannabis Lifestyle TV awhile back with some good things that you can do to increase yield. Watch it here:
Do you have a par meter or did you go by the mfg suggested par/ distance diagram? Did you measure wattage draw to see if it is actually drawing 600 from the wall ? Your last picture shows a power rating of 245W.......
Lighting is only 1 part of a whole when it comes to managing the enviroment. If it is a true 600 watt light ( lower cost lights often are not ) you should be fine. If you do not have a expensive par meter ( $500), search the play store for ppfd meter, I use this to get a baseline par reading. I use 400 seedling 600 veg and 900 flower. Also research your light to see what you find regarding true wattage/ power draw. This all together will be the true values of your light and not the numbers someone came up with to sell the light.
Not sure if you have autos or photos. If they were autos then that amount from that light doesn't seem to bad to me, especially your first grow. You will find that your light is top 3 of items, that improving will always result in better yields. Cannabis is one of the most light hungry plants around.