Map Your Plant Light
Many indoor plants suffer because it is easy to misjudge how much light really reaches them. Use this mapper to calculate estimated foot-candles (FC) based on your window type, distance, and seasonal changes. Save setups to your personal Plant Room planner below.
Window Details
Estimated Light Output
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Understanding Indoor Plant Light
Getting light levels right is the most common hurdle for indoor gardening. We measure this light in foot-candles (FC) or lux. Most care tags use vague terms like "bright indirect light," which leaves too much room for error. The mapper above uses standard daylight averages to translate window placements into practical numbers you can actually use.
How distance changes everything
Light drops off dramatically the further you move away from the source. This is the inverse square law in action. A plant sitting 1 foot away from a South window might receive 800 FC, but moving it just 4 feet into the room can drop that usable light to 150 FC. What looks perfectly bright to human eyes is often a dark cave to a Ficus or Monstera.
Common signs of incorrect light
Watch your plants for physical clues. If a plant isn't getting enough light, it will stretch towards the window (etiolation), grow smaller leaves, or drop its lower leaves out of nowhere. Soil will also stay wet for much longer than usual because the plant is not actively photosynthesizing to use the water.
If the light is too intense, you will see bleached leaves, crispy brown edges (sunburn), or colors fading completely away from the foliage. This often happens if you move a nursery plant directly into a harsh West or South window without a transition period.
Artificial light conversion and assumptions
This calculator focuses entirely on natural daylight. If your window is heavily blocked by trees and outputs less than 50 FC, you will likely need a grow light regardless of what direction the window faces. When shopping for supplemental lights, standard household LEDs do not provide the full spectrum or intensity needed. Grow lamps usually advertise Photosynthetic Photon Flux Density (PPFD). A standard rule of thumb for low-light houseplants is around 30 to 50 PPFD, while high-light succulents require 200 to 500+ PPFD for at least 12 hours a day.
Troubleshooting yellow leaves
While many people assume yellow leaves mean overwatering, they can also signal extreme light starvation. If a plant has spent three months in a dark hallway, its root system begins to rot because it cannot process water. Always correct the light source before you try to "fix" the watering schedule.