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Plant Lighting Calculator

Learn how long and how strong to keep your grow lights on to maximize yield with minimum electricity cost.

Your Application

Cannabis

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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/m²s

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Daily Light Integral

A daily light integral (DLI) of 30 - 45 is optimal for most cannabis plants.

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Lighting Duration

The optimal lighting duration for cannabis is dependent on the growth phase and can range from 12 hours up to 24 hours.

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Lighting Intensity

PAR levels of up to 1100 umol are optimal for cannabis plants.

Week 3

Houseplants

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How it Works

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
PPFD
Lighting Duration
hours

Fruits & Vegetables

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How it Works

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/m2d
Measured PPFD
iYou can accurately measure PPFD with our free Grow Light Meter App
PPFD
Lighting Duration
hours
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The Science Behind

Calculation Basis

Our calculation is primarily based on the optimal daily light integral (DLI) for each stage of the cannabis plant.

Recommended cannabis DLI for the full growth cycle. Image taken from gpnmag.

The DLI acts as the main measure of the actual amount of light the plant receives and is a product of light intensity (PAR) and light duration.

PAR and PPFD

Photosynthetically active radiation (PAR) measures light which is used by plants for photosynthesis. It is commonly measured as PPFD in µmol/m²s 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.