Do I have enough light?

Hi All,

I am setting up a new room and i am planning on having 500-800umols for the canopy.

Is that enough?

I want to add co2 this time round... I havent used co2 before.

No way to know without a PPFD number or how big your grow space is. PPFD is umols calculated for a given space. 800 umols in a 20 by 20 foot room not even close to enough light. 800 umols in a 1x1 foot tent would be more then enough. So pretty tough to answer that question without more info

JavaCo said:

No way to know without a PPFD number or how big your grow space is. PPFD is umols calculated for a given space. 800 umols in a 20 by 20 foot room not even close to enough light. 800 umols in a 1x1 foot tent would be more then enough. So pretty tough to answer that question without more info

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Im saying at the canopy I will have between 500-800 umols. Im using a par meter and thats the reading it is giving me. Are you saying that reading is PPFD? it says uMols?

Porky101 said:

Im saying at the canopy I will have between 500-800 umols. Im using a par meter and thats the reading it is giving me. Are you saying that reading is PPFD? it says uMols?

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I like around 1000 umols on the par meter across the canopy. I'm not using CO2.
I've a friend using 1500 umols and he is using CO2.

35-55 wqtts per sq ft.

Porky101 said:

Im saying at the canopy I will have between 500-800 umols. Im using a par meter and thats the reading it is giving me. Are you saying that reading is PPFD? it says uMols?

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The hydrofarm par meter measures umol m/s which is PPFD so if yours is like that then you are measuring PPFD. Thought maybe you got your umol/s from a one of the LED manufacturers calculators. But i wouldn't run co2 at those light levels going to have to have over 1000 umol m/s before I would mess with adding any. Fluence says you get co2 limited @ 500 umol m/s though so who knows maybe you will see a increase in yield here is a good write about high ppfd by fluence http://fluence.science/wp-content/uploads/2016/09/High-PPFD-Cultivation-Guide-9.27.16.pdf

JavaCo said:

The hydrofarm par meter measures umol m/s which is PPFD so if yours is like that then you are measuring PPFD. Thought maybe you got your umol/s from a one of the LED manufacturers calculators. But i wouldn't run co2 at those light levels going to have to have over 1000 umol m/s before I would mess with adding any. Fluence says you get co2 limited @ 500 umol m/s though so who knows maybe you will see a increase in yield here is a good write about high ppfd by fluence http://fluence.science/wp-content/uploads/2016/09/High-PPFD-Cultivation-Guide-9.27.16.pdf

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Ok your right, yes mine is showing umol m/s. So that is the same as PPFD.


I am currently using the CXB 3590 @ 35W SQFT. I am getting under 1,000umols at the canopy, I am getting 800. I have the option of adding more cobs or I add some CMH bulbs and get some extra UV light, what you think?

I want to add CO2.

According to that document you linked too, over 500umols / ppfd and extra co2 is beneficial. So I think I have enough light to suppliment co2. I think I will keep my co2 levels = to my umol levels. 800 umols / ppfd = 800ppm co2.