Reference
Houseplant Light Levels Explained
The short answer
Light level translates roughly to window direction: north-facing windows give low light (about 25-100 foot-candles), east or west windows give medium-to-bright light (about 100-500 foot-candles), and south-facing windows give high light (about 500-1000 foot-candles). A spot getting 4-6 hours of direct sun, like an unshaded south bay window, is over 1000 foot-candles.
Most houseplants - even low-light-tolerant ones - grow best in bright, indirect light, and few besides cacti and succulents handle the heat of direct southern exposure. Light also drops off fast as you move away from the window, so distance matters as much as direction.
Light levels by window direction
University of Maryland Extension groups indoor light into levels by window exposure. Low light (about 25-100 foot-candles) comes from north-facing windows or artificially lit rooms. Medium-to-bright light (about 100-500 foot-candles) comes from east or west-facing windows.
High light (about 500-1000 foot-candles) comes from south-facing windows or some west-facing windows, and direct indoor sunlight (over 1000 foot-candles) means 4-6 hours of direct sun, such as in a sunroom or an unshaded south-facing bay window. West windows run hotter than east windows because of the stronger afternoon sun.
Matching plants to light
Most houseplants - even those that tolerate low light - grow and look their best in bright, indirect light. So 'low light' usually means 'will survive,' not 'prefers.' If you want strong growth, err toward brighter indirect exposure.
Very few plants handle the light and heat of direct southern exposure; cacti and succulents are the main exception. For most foliage plants, an east or west window, or a few feet back from a south window, is ideal.
Distance and other factors
Direction isn't the whole story. Light intensity depends on the distance from the source and decreases rapidly with increasing distance - a plant right at the glass gets far more light than one across the room, even at the same window.
Curtains, insect screens, the season, shade from trees or nearby buildings, and even how clean the window is all cut the light a plant actually receives. If a plant is stretching or fading, move it closer to the window or to a brighter exposure.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Maryland Extension - Lighting for Indoor Plants — Classifies indoor light by window direction and foot-candles: low light 25-100 FC (north windows/artificial), medium-bright 100-500 FC (east/west windows), high 500-1000 FC (south/some west windows), and over 1000 FC (4-6 hours direct sun, sunroom/unshaded south bay window); notes light intensity decreases rapidly with distance from the source.
- Missouri Botanical Garden - Indoor Plants (Houseplants) — Advises that most houseplants, even those that do well in low light, grow and look their best when provided with bright, indirect light, and that few plants survive the light and heat intensity of direct southern exposure with the exception of cacti and succulents.