Getting the placement of your grow light right is critical to making sure it is delivering the right amount of light in your plant.
Grow Lights and Daily Light Integral (DLI)
In order to know how far your commerical led grow light strips should be from your plants, there are a few things we need to know. Firstly, we need to understand the DLI or Daily Light Integral for your plants. This is the plant worlds’ equivalent to us humans and our calories. If you don’t give them enough light energy each day, they will wither and likely die.
Grow Light Distance is Impacted By Grow Light Timing
The next thing we need to know is the optimal light duration for this plant. As we discussed in How Long Should You Leave Grow Lights On For? all plants have an optimal duration of light – which will either encourage or discourage flowering – depending on what your objectives are.
Grow Light Distance is Determined by Grow Light Power (PPF)
Once we know the ideal DLI and duration of light we have an ideal PPFD. The PPFD that a grow light delivers is a function of two things: 1) distance from the grow light, and 2) power of the grow lights for indoor plants.
The best distance for placing a plant from a led grow lights samsung is a function of the target PPFD you are trying to achieve (flow rate of light) as well as the power of the light. In the lighting world, we measure this ‘power’ as PPF or photosynthetic flux. All grow lights perform a similar function; they convert Watts from your wall socket into PPF for the plants. All grow lights are not created equal, however, and some are much more efficient at converting Watts into PPF than others. In fact if we divide these numbers together we get PPF/W, PPE, or ‘efficacy’.

Best Grow Light Distance For Lettuce And Leafy Greens?
Once you start getting into leafy greens like lettuce and herbs, the light requirements do start to increase, and it is, therefore, important to be delivering the right quantity of light. If you wanted to take the ‘scientific’ approach to this, the theory above as well as Grow Lights For Indoor Plants – How To Measure It, and Understanding Watts, PPF, PPFD and DLI will guide you through it.
Best Grow Light Distance For Seedlings?
When plants are young, at the seedling stage, their energy requirements are typically pretty low. Some varieties of edible plants actually prefer complete darkness to germinate.
Generally speaking though, any window that has a decent amount of light coming through it is going to provide ample light for seed starting. If natural light isn’t an option for you, then don’t get too hung up on weed grow lights placement – just use whatever you have and make sure it is no closer than the ‘lettuce’ recommendations below for grow light distance from seedlings.