GARDENER'S READING ROOM
Indoor Plants

The Right Light

Congratulations! You’ve decided to buy a houseplant. You walk into our Houseplant Department, ask for an “easy-care” plant, and the first thing out of our mouths is “How much light do you have?”

Light affects what plant you should buy and where you should put it. Light = energy for plants; it also tells plants when to flower, how fast to grow, etc. Each species has minimum and maximum light needs for normal growth. If a plant gets just enough light to produce food at the same rate it uses energy, it’s like someone spending exactly what they earn. If the plant is in lower light, it has to draw energy from its reserves to survive. Ideally the plant gets a little extra light so it can build up its reserves - like you saving for a rainy day.

The good news is that plants can adapt to higher or lower light (within reason). This is called acclimatization. Plants acclimatize to lower light by slowing down and getting that stretched-out look. The leaves get greener, thinner and longer, and go horizontal. New growth is smaller and weaker. If the plant stays below its minimum light requirement too long, it will eventually decline and die. A plant acclimatizing to higher light makes its leaves thicker and more vertical to reduce the light hitting the surface. Leaves bleach out. If a plant is forced into too much light too rapidly it can sunburn - or burn to a crisp.

At Sky, we use color-coded tags to indicate what intensity of light a houseplant likes best. Our care tags give further information. Does this mean you can’t get a plant if you don’t have the right light? Not necessarily - you might be able to acclimatize it, or supplement with artificial light. Ask!

One final note: in general, the more light a plant gets, the more water it needs - which is why you cut down on watering in the winter. We’ll be discussing houseplant water issues in the winter Skylights. Or stop by - we’re always happy to talk with you.

HIGH LIGHT (yellow tag on houseplants) Within 5 feet of a south, west or east facing window that gets direct sun. Easy way to tell you’re in high light: your hand casts a dark, distinct shadow.

MEDIUM LIGHT (lavender tag) Within 5 to 8 feet of a sunny window or directly in a north-facing window. Easy way to tell you’re in medium light: your hand casts a pale, blurry shadow.

LOW LIGHT (blue tag) Farther than 8 feet from a sunny window; corners of rooms; hallways; entryways. Easy way to tell you’re in low light: no shadow, or barely visible.

By Mary Ann Greco
Skylights Autumn 2004, Vol 18, No. 3

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