Understanding Plant Light Requirements
Light is food for plants. Get it right, and your plants will flourish. This guide decodes confusing light terms and helps you find the perfect spot for every plant.
Light Level Definitions
What do these terms actually mean? Here's a practical breakdown.
Bright Direct
10,000-50,000+ lux
Direct sunbeams hitting the plant. Usually within 2 feet of a south-facing window with no obstruction.
Good for: Cacti, most succulents, herbs, some flowering plants
Note: Can burn many houseplants, especially tropical foliage.
Bright Indirect
3,000-10,000 lux
Bright but diffused light. Near windows with sheer curtains, or a few feet back from sunny windows.
Good for: Most tropical houseplants, Monstera, Pothos, Ficus, Philodendron
Note: The most versatile light level for houseplants.
Medium Light
1,000-3,000 lux
Several feet from windows, or north-facing windows. Rooms are comfortable but not brightly lit.
Good for: Peace Lily, Dracaena, Pothos, Spider Plant, most ferns
Note: Growth will be slower than in bright light.
Low Light
100-1,000 lux
Far from windows, interior rooms, or heavily shaded. You might need a lamp for comfortable reading.
Good for: ZZ Plant, Snake Plant, Cast Iron Plant, Pothos (survives)
Note: Very few plants thrive here; most just survive. No flowering.
Window Direction Guide
South-Facing
Northern Hemisphere
Brightest, direct sun most of the day
Best for: Succulents, cacti, herbs, sun-loving plants
Tip: Use sheer curtains to create bright indirect light for tropical plants.
East-Facing
Northern Hemisphere
Gentle morning sun, bright indirect afternoon
Best for: Most houseplants, tropical foliage
Tip: Ideal for many plants. Morning sun is less intense than afternoon.
West-Facing
Northern Hemisphere
Bright indirect morning, intense afternoon sun
Best for: Plants that tolerate some direct sun
Tip: Afternoon sun is intense. Move sensitive plants back or use curtains.
North-Facing
Northern Hemisphere
Consistent low to medium indirect light
Best for: Low-light tolerant plants
Tip: No direct sun year-round. Good for ferns, ZZ plants, Snake plants.
Southern Hemisphere? Flip north and south. North-facing windows get the most sun, south-facing the least.
Signs of Light Stress
Too Much Light
Bleached or faded leaves
Chlorophyll breaks down from too much light
Brown, crispy patches
Sunburn damage on leaves
Curling or wilting in sun
Plant trying to reduce light exposure
Soil dries extremely fast
High light increases evaporation
Too Little Light
Leggy, stretched growth
Plant reaching toward light source
Small, pale new leaves
Lack of energy for proper growth
No flowering
Insufficient light for bloom production
Dropping lower leaves
Plant sacrifices old leaves to survive
Leaning toward window
Phototropism—growing toward light
Grow Lights Guide
When natural light isn't enough, grow lights can help. Here's what to know.
LED Grow Lights
Pros
- Energy efficient
- Low heat
- Long lifespan
- Full spectrum available
Cons
- Higher upfront cost
- Quality varies widely
Best for: Most houseplant supplementation, seedlings, serious plant parents
Fluorescent (T5/T8)
Pros
- Affordable
- Low heat
- Good for shelves
Cons
- Less efficient than LED
- Bulbs need replacing
Best for: Seedlings, low-light plants, shelf setups
Incandescent Grow Bulbs
Pros
- Very cheap
- Fits standard sockets
Cons
- Inefficient
- Produces heat
- Short lifespan
Best for: Occasional spot supplementation (not recommended for primary light)
Measure Light with Your Phone
BotanAI includes a built-in light meter that uses your phone's camera to measure lux levels. Point at your plant's location and get instant readings with recommendations.
Frequently Asked Questions
What does "bright indirect light" actually mean?
Bright indirect light means a well-lit area where the sun doesn't directly hit the leaves. Think of a spot near a sunny window but to the side, or behind a sheer curtain. The room is bright enough to read comfortably without artificial light, and objects cast soft (not sharp) shadows.
How do I measure light levels at home?
Use a free light meter app on your phone (search "lux meter"). Point your phone at where the plant's leaves would be, facing the light source. Take readings at different times of day. 1000+ lux is medium light, 3000+ is bright indirect, 10000+ is bright direct.
Can plants get light through windows?
Yes, but windows filter some light. Single-pane windows allow more light than double-pane. Dirty windows, screens, and tinted glass reduce light significantly. A spot right next to a window receives much more light than a few feet away.
How long should grow lights be on?
Most houseplants need 10-14 hours of light daily. Use a timer for consistency. Plants also need a dark period, so don't run lights 24/7. If supplementing natural light, run grow lights during evening hours to extend the "day."
Find the Perfect Spot for Every Plant
BotanAI's light meter helps you measure and match plants to the right location.
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