Lighting House Plants

Lighting is one of the most vital components of plant care. All plants need light in order to live and grow. No plant can survive in absence of light. However, there is a range of optimum light levels, which varies by species. Be sure to grow your plant in its proper light conditions. Plants that are grown in light that is too low may develop a “leggy” or pale appearance, or fail to thrive or bloom. Plants that are grown in light that is too high may develop sunburn.

The intensity of light is measured in footcandles (f.c.). One footcandle is defined as the amount of light cast by a candle on a surface 1 foot away. Light intensity can be measured using a light meter. Below are the classifications of low, medium and high light plants based on footcandle measurements. The measurements are listed in both the minimum light needed for survival, and also in the preferred optimum amount needed for proper growth.

The intensity and duration of light that a plant receives is dependent on its location. Below are descriptions for the light intensity found in North, South, East, and West facing windows.

• South Window – Southern windows receive bright light during the winter months, but in summer months, the light intensity is much lower, and plants in south facing windows will only receive bright sunlight during noontime in the summer. Plants with high light requirements are well suited for Southern exposures.
• North Window – North Facing Windows receive a constant supply of low light throughout the year. The intensity of the light is also fairly consistent throughout the day. Low light plants and a few tolerant medium light plants are suited for Northern exposure windows.
• East Window – Many plants are most tolerant of an Eastern facing window. Eastern exposure windows receive bright light from sunrise until noon. Medium light plants and some high light plants are well suited for Eastern windows.
• West Window – The Western window is similar to the Eastern window in terms of light intensity and light duration. This location is suited to medium light plants and some high light plants.

Also, the light intensity will also be influenced by how clean the window panes are, and whether there is any type of overhang over the window, or objects such as trees blocking the window. Additionally, the plant’s distance from the window will also influence the light intensity it receives. For instance, a plant placed a few feet away from a window will receive much lower light than a plant placed directly next to the window.

Some general light tips:

• Plants that bloom will need high light
• Plants with colorful or variegated foliage will need high light
• Plants with small, or narrow leaves will need more light than those with large, wide leaves
• Large leaved, green foliage plants will usually need medium to low light

Written by Adrienne Kleintop