How to Choose Grow Lights
Keeping it Simple
Our goal is to keep this simple and easy to understand.
Follow along to learn how to choose the best lights for your plants,
making you miles ahead in two easy steps!
Step 1: How to Measure Light?
There are many ways to measure light, but not all of them work for plants.
Common measurements, like lumens and kelvin, don’t work for plants.
Here we help you know what to look for when choosing lights.
Meet Photon!
For the sake of simplicity, we will use this character as the unit of light.
Light acts like particles so we will use our friend here as the example of a group of light particles.
Photon is made up of many colors!
Plants use different colors for different things. But a balanced diet is important!
For our purposes, Photon is made up of all colors in a full-spectrum grow light.
What is Color?
Color acts as a wavelength. Like how different musical notes vibrate at different speeds, photons are different colors by how they vibrate. So a low note (long wave) would look like a purple or blue and a high note (short wave) would look like an orange or red. There is a range of colors that all plants use (the PAR range) shown in the diagram above. When you hear about "full-spectrum grow lights" it means the rainbow it makes is within this PAR range of colors.
Step 2: The Measurements
Almost there! Now we will go through the 3 main terms to look for when choosing grow lights. For this page we will be using grow lights as our example of a light source, but sun light can be measured the same way!
How Much Light Does My Grow Light Make Every Second?
PPF (Photosynthetic Photon Flux)
This unit is to show how many photons will spit out every second. This doesn’t mean how bright it is. A light twice as long as another can spit out the same amount of photons, but the smaller light will be twice as bright. So how do we tell how bright it is?
Measure Light Brightness
PPFD (Photosynthetic Photon Flux Density)
This unit is the one most people are looking for. PPFD is how bright the light is at a given distance. We measure this by seeing how many photons land on a surface (square meter) every second. The brighter the light, the more photons will hit that surface.
Some plants like shade and others full sun. With PPFD we can communicate just how bright the plants like to be. For example: a shade loving fern likes a PPFD of 20-40 while a tree that loves full sun can want a PPFD as large as 1000! We provide our grow light PPFD ranges and the PPFDs that our plants like for happy and healthy plants!
Grow Light Energy Efficiency
PPE (Photosynthetic Photon Efficiency)
Reducing energy costs is important both for our planet and our wallet. And with grow lights it is no different! This unit is used to measure the growlight's energy efficiency. The larger the unit, the more efficient the grow light is. We have come a long way with LED light efficiency and we still are finding ways to make them even better!
And that's it! Hope this helps understand grow lights and what to look for.