Naturally, in almost every care instruction guide for a plant (indoor or outdoor), you’ll see a section on how much light the plant should receive. But the level of sunlight a plant should get is always described in terms like “high” or “bright” or “medium indirect,” and it’s not always obvious what that means.
Well, first, the difference between direct and indirect light is just whether the sun is hitting the plant straight on, or if instead the light is filtered through some window shades or translucent medium. A lot of indoor plants don’t like to get much direct sun, and even though they may like a lot of light, they don’t want to be soaking up rays all day.
But what consitutes “bright” light vs. “medium” light vs. “low” light?
A quick way to tell is just with a hand test. Take a piece of paper or some other plane surface and hold your hand about a foot away from it, between it and the light source. If you can’t see much of a shadow or it’s very faint, you’re getting low light. In a medium light situation you’ll see a blurry or fuzzy shadow of your hand, and in bright light you’ll get a crisp clear shadow.
Often if a plant is receiving insufficient light, it’ll cause spindly stems (that are reaching out to get closer to a light source), yellow foliage, and leaf drop. Too much light results in burned leaves or pale foliage. But these are just general guidelines – some plants behave differently.
Note that if you need to give a plant more light, being close by a large unobstructed south-facing window will likely give you the best brightest sunlight. Many houseplants also thrive in artificial light, thought this is usually a low light situation, because unless you have exceptionally bright indoor light bulbs it’s not nearly as strong as natural sunlight, which provides a broad spectrum of light