Light Availability Checker for Houseplants

Disclosure: Amazon links on this page are affiliate links, so this site may earn a commission at no extra cost to you. Commissions don’t decide which products are recommended. See the full affiliate disclosure.

You don't need a lux meter to know what light your plant will actually get. Answer five questions about your window — direction, distance, obstructions, hemisphere, and floor — and this tool returns a qualitative light category plus a list of plants from our catalog that fit your exact conditions.

How the scoring works

The tool converts your window situation into one of five qualitative light categories using an additive scoring model. Each category corresponds to a range of light intensity, though actual foot-candle values vary enormously with window size, sky conditions, season, and geographic latitude — which is why we use ranges and explicitly note that "actual measurements vary widely."

Direction as the starting point

Window direction is the single biggest determinant of indoor light. In the Northern Hemisphere, a south-facing window receives the most direct sun across the entire day because the sun arcs through the southern sky. A north-facing window, conversely, receives no direct sun at all — only diffuse skylight. East windows get bright morning sun that softens to gentle indirect light by afternoon. West windows flip that: cooler morning indirect light followed by the hottest afternoon direct sun.

In the Southern Hemisphere, this is exactly reversed: north-facing windows are the brightest, south-facing windows are the dimmer ones. The tool applies this automatically when you select your hemisphere.

NC State Extension's Plant Toolbox describes light conditions in qualitative categories rather than foot-candle thresholds — deep shade (less than 2 hours to no direct sunlight, as on its parlor palm entry), partial shade (direct sunlight 2–6 hours) and full sun (6 or more hours of direct sunlight, both as on its air plant entry). That makes sense: the same foot-candle reading can mean very different things depending on the duration and spectral quality of the light.

Distance from the window

Light intensity drops off sharply with distance from the source. The inverse-square law governs this physically, but for practical indoor purposes, the pattern is consistent: Illinois Extension, for example, rates a spot up to 5 feet from a south window as high or bright light (about 300 foot-candles) and a spot 3 to 10 feet away as medium light (about 150 foot-candles), even with nothing obstructing the view. The tool subtracts one light category point for a distance of 2–6 feet, and two points for 6 feet or more.

MU Extension notes that even low-light plants usually do not receive enough light at distances greater than 10 feet from an average window.

Obstructions: curtains and outdoor shading

Curtains change how much light reaches a plant: UMD Extension lists them among the factors that affect indoor light and suggests a sheer curtain as a light shade against strong sun. That can be enough to shift the experienced light category. Heavy curtains or closed blinds block dramatically more — effectively removing the window as a light source while closed. Outdoor trees, building overhangs, and neighboring structures reduce sky exposure and eliminate the possibility of direct sun, even through an otherwise clear window. The tool penalizes each of these accordingly.

Floor height

Ground floor units in urban environments frequently have outdoor obstructions — street trees, neighboring buildings, fences — that upper floors do not. When you select "ground floor" and have outdoor obstructions checked, the tool applies an additional deduction to capture this compounding effect.

Plant recommendations by light category

The plant recommendations in the tool are drawn from species we have detailed care articles for. Each recommendation is consistent with how extension sources characterize that species' light requirements:

Insufficient light (score 0): Parlor palm, snake plant, and ZZ plant are the most shade-adapted species in our catalog. Per NC State, ZZ plant can grow under fluorescent light alone — but even these species eventually decline without some photosynthetically active light input. A supplemental grow light is the right solution here.

Low light (score 1): Pothos, snake plant, ZZ plant, parlor palm, and heartleaf philodendron. All five are described as low-light tolerant in their NC State Plant Toolbox entries (pothos, snake plant, ZZ, parlor palm, heartleaf philodendron). This is the category of dim north windows, deep room interiors, and office spaces with some daylight from a distant window.

Medium indirect light (score 2): Pothos, heartleaf philodendron, peace lily, prayer plant, spider plant, Boston fern, and calathea. Per MU Extension, peace lily adapts to low light but needs medium light to flower, and Boston fern tolerates low light but prefers a medium light level; NC State advises keeping peace lily out of direct sun. Calathea is also in this category — NC State's Goeppertia entry lists medium light — though it demands consistent humidity alongside its light preference.

Bright indirect light (score 3): Monstera, fiddle leaf fig, rubber plant, anthurium, alocasia, and pilea peperomioides. These larger-leaved tropicals need abundant light to produce the growth they're known for — large fenestrated leaves on monstera, broad glossy leaves on rubber plants — but direct midday sun will scorch them. NC State's entry for monstera deliciosa lists partial shade as the preferred condition, which aligns with bright indirect light in interior terms.

Bright direct light (score 4): Jade plant, aloe, air plants, and anthurium (with protection from the hottest afternoon rays). Succulents and cacti-adjacent species like jade plant need the highest foot-candle levels and will etiolate — stretch toward light — in anything dimmer. Per NC State, jade plant needs "a sunny location indoors that also provides some afternoon shade," and bright light is "essential for good plant health."

Frequently asked

My room has two windows facing different directions. Which do I use?

Use the brightest window that is closest to where you plan to place the plant. If a plant will sit between two windows, you can run the tool twice and consider the average — a plant equidistant between an east and a south window in the Northern hemisphere is likely in the bright indirect range for most of the day.

Does a skylight count as a "south window"?

A skylight provides overhead light — typically bright indirect for most of the day, with a direct sun window around midday when the sun is nearly vertical. For practical purposes, treat a skylight as equivalent to a bright indirect south window and use the results for score 3 as your starting point. Actual intensity depends heavily on the skylight's size and any diffusing glass.

The tool says "bright direct" but my plant keeps looking sunburned. What's wrong?

Actual direct sun intensity varies significantly by latitude, season, and time of day; a south window in winter is much gentler than the same window in summer. If your plant shows leaf scorch or bleached patches, do what UMD Extension suggests for strong summer sun: move it farther from the window, or add a sheer curtain. Use the light meter calculator to measure your actual foot-candle level and compare it against your plant's known tolerance.

Sources: NC State Extension Plant Toolbox — Chamaedorea elegans · NC State Extension Plant Toolbox — Zamioculcas zamiifolia · NC State Extension Plant Toolbox — Dracaena trifasciata · NC State Extension Plant Toolbox — Epipremnum aureum · NC State Extension Plant Toolbox — Monstera deliciosa · NC State Extension Plant Toolbox — Spathiphyllum · NC State Extension Plant Toolbox — Tillandsia · NC State Extension Plant Toolbox — Goeppertia · MU Extension — Lighting Indoor Houseplants · Illinois Extension — Lighting · UMD Extension — Lighting for Indoor Plants