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Our Jargon-Busting Guide to Horticultural Lighting: PAR, PPF, and PPFD

LED lights have now become the dominant option in horticultural lighting and it’s no wonder why. Their ease of use, unmatched efficiency, and full-spectrum capability make them the obvious choice when it comes to getting the best results for your plants.  

But alongside such popularity also comes uncertainty. With so many options flooding the market it can be overwhelming when choosing the right LED for your needs.  

By now it’s well known that LED means “Light Emitting Diode”, but what about all the other acronyms crammed into the descriptions of the market’s most popular lights? 

Continuing from our post on PPE in this piece we walk you through some of the need-to-know jargon surrounding LEDs. 

The Big P: Photosynthesis 

Some of the most common acronyms you will come across relate to how well your plants will grow under LEDs. So where better to start than with the key principle in horticulture, photosynthesis.  

Photosynthesis is the process where plants capture carbon dioxide from the air, freeing carbon particles and – thanks to light – turns them into organic living tissue like leaves, whilst releasing oxygen back into the air.  

The Three P’s: PAR, PPF, and PPFD

Horticultural lighting is primarily focused on the quality and quantity of light you need to optimise photosynthesis. So we need to be able to quantify how well an LED will influence this process. 

PAR, PPF, and PPFD are, some of the most common acronyms you will come across when choosing LEDs.  

But what do they mean? And why should you care? 


PAR stands for “Photosynthetic Active Radiation” and simply put it describes the waveband of light used to support photosynthesis in a plant. It is not a measurement of light but represents the useful wavelengths used by plants for photosynthesis. This is particularly important for growers as it is used, alongside the strength and duration of lighting, to establish the total amount of light needed to reach your desirable plant outcomes.  


PPF stands for “Photosynthetic Photon Flux” and is simply the amount of PAR light emitted from a particular fixture per second that can be used by the plant to photosynthesise.  


Similarily, PPFD stands for “Photosynthetic Photon Flux Density” and it measures the PAR light amount per second that lands on a square metre. PPFD is essential to light planning as it ensures your plants are getting the correct amount of light. 

These measurements are integral to the light planning process and optimising your grow space and yield. It’s vital growers assess them correctly. 

Getting Horticultural Lighting Right 

Measuring what your plants need can take a great deal of patience and mathematical nous.  

Working with a trusted and experienced partner is a good way to eliminate these troubles. Get in touch with one of our horticultural experts today and let us help you optimise your grow space.