Calculate Day Light Integral DLI using a Photosynthetically Active Radiation PAR sensor (also known as a PAR or Quantum Meter)

Peter · December 12, 2023, 7:38pm

DLI Maps for the United States. These are a great way to learn what the DLI is where you live at any time of year - good talking point and poster to print out for a classroom to discuss light as an environmental variable.

citation: https://www.researchgate.net/figure/Maps-of-monthly-outdoor-DLI-throughout-the-United-States-Source-Mapping-monthly_fig1_242551992

How this map can be used to help students create their own custom recipes for the MV1:

Start by deciding what you want to grow.
- Then try to determine where that plant is normally grown and at what time of year (Google it or check out Plants Well-suited for Controlled Environment Agriculture - #4 by Peter)
  - Other posts in that thread explain how to choose plants that grow quickly.
Using the known growing seasons, calculate the ‘average’ DLI that the plant would receive during its phases of growth.
- Use the map in the first link to calculate the DLI for that location and time.
- For shorter duration plants (leafy greens) this is shorter - 2-3 months. If it’s longer, worry more about the period when the fruit would be ripening - whenever it gets the most light.
Convert that DLI into a ‘recipe’ which can be run on the MV1.
- This table shows the settings for the three pre-made DLI ‘recipes’ (DLI: 30, DLI: 21, DLI: 17) that you can pick from to run in your MV1: What does a MARSfarm recipe do? What is JSON? (ChatGPT-4 Response) - #4 by Peter
  - Honestly, those three are great place to start for growing any type of leafy green.
  - DLI 30 = too much light for most leafy greens.
- Keep in mind, the conversion we make assumes plants that are ~6" tall.
  - If you’re growing a tomato or pepper - the DLI will be even higher closer to the lights.
- Other posts earlier in this thread show what a PAR meter is and how we use it to calculate DLI settings for each recipe.