Light Availability Checker for Houseplants

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.

Disclosure: I buy what I recommend and test it personally. Amazon links may earn a commission at no extra cost to you — it does not affect picks. See the full affiliate disclosure.

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.

Per NC State Extension's Plant Toolbox, light condition descriptions for indoor houseplants use qualitative categories — deep shade (fewer than 2 hours of direct sun equivalent), partial shade (2–6 hours), and full sun (6+ hours) — rather than specific foot-candle thresholds, because 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: a plant sitting within 2 feet of a south window may receive bright direct sun while the same plant moved to 6 feet back could be receiving medium indirect light, 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.

Missouri Botanical Garden's plant care guides consistently note that most tropical foliage plants should be placed "near" a window — within a few feet — for adequate light, even for species described as tolerant of lower light conditions.

Obstructions: curtains and outdoor shading

Sheer curtains are more light-blocking than most people expect. A sheer fabric can reduce transmitted light by 20–50%, which is 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 and botanical garden 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 is the right solution here.

Low light (score 1): Pothos, snake plant, ZZ plant, parlor palm, and heartleaf philodendron. All five are confirmed low-light tolerant by NC State Extension. 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 Missouri Botanical Garden, peace lily and Boston fern are classic medium-light species — they need some light for growth but will scorch in direct sun. Calathea is also in this category, 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 requires "bright direct" light and will grow leggy without it.

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 January at 45°N latitude is much gentler than the same window in July. If your plant shows leaf scorch or bleached patches, move it back a foot or two from the glass, 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 · Missouri Botanical Garden — Plant Finder