PPFD, PAR, Foot-candle or Lux: What Is the Difference?
Horticulture
Your Application
Cannabis
Step 1
Plant Growth Stage
Select what comes closest based on a regular 15 week schedule
Step 2
Lighting Duration
Specify the lighting duration within a 24 hour period
Step 3
Lighting Intensity
Use your PAR meter to measure PPFD at your plant’s canopy
Result
Vegetative
18
Hours
420
PPFD
µmol/m²/s
Daily Light Integral
A daily light integral (DLI) of 30 - 45 is optimal for most cannabis plants.
Lighting Duration
The optimal lighting duration for cannabis is dependent on the growth phase and can range from 12 hours up to 24 hours.
Lighting Intensity
PAR levels of up to 1100 umol are optimal for cannabis plants.
Houseplants
Input your values to calculate your individual plant lighting recommendation.
The calculation is based on the daily light integral (DLI), which is the main measure for an optimal amount of light for plants.
Plant Species / Genus
Measured PPFD
iYou can accurately measure PPFD with our free Grow Light Meter App
µmol/m²/s
Lighting Duration
hours
Fruits & Vegetables
Input your values to calculate your individual plant lighting recommendation.
The calculation is based on the daily light integral (DLI), which is the main measure for an optimal amount of light for plants.
Plant Family
DLI Requirement
iIn case you want to manually set the DLI, you can add it directly in this field
mol/m²/d
Measured PPFD
iYou can accurately measure PPFD with our free Grow Light Meter App
µmol/m²/s
Lighting Duration
hours
Back to Start
The Science Behind
Calculation Basis
Our calculation is primarily based on the optimal daily light integral (DLI) for each stage of the cannabis plant.
The DLI acts as the main measure of the actual amount of light the plant receives and is a product of light intensity (PPFD) and light duration (photoperiod).
CO₂ Supplementation
Our cannabis DLI calculator assumes that you're not supplying additional CO₂ to your cannabis grow. If you do so, we recommend to increase your PPFD by 25%.
PAR and PPFD
Photosynthetically active radiation (PAR) measures light which is used by plants for photosynthesis. It is commonly measured as PPFD in µmol/m²/s and the most relevant measurement for grow lights.
Don’t Have a PAR Meter?
No problem! We recommend our free Photone Grow Light Meter app that is both very accurate and easy-to-use to measure your light's PPFD intensity with your smartphone or tablet.
Additional Resources
Optimally lighting your cannabis plant is dependent on a lot of factors and our calculator can only provide an approximate assumption. If you want to learn more about lighting for cannabis, we recommend the article about it on our blog.
