CO-Horts Blog

Monday, January 22, 2018

Avoid Leafy Office Follies

By Carol O'Meara, Boulder County Extension

Keeping green and growing houseplants as office companions?  Spending long days in cubicles and offices can make the hardiest gardener pine for leafy companions.  But not all offices are ready for green thumbs; I’ve heard tales of well-meaning employees locked in battle with supervisors.  One side thinks plants need round-the-clock illumination, the other views plants as energy gluttons draining the world in a vampiric thirst for light.

Before your workplace engages in a war of wattage, clear up confusion on how much, and how long, plants should be illuminated.  Here are a few tips on lighting your foliaged office mates:

Light is essential for plant growth, and for your plants to be happy, keep three things in mind: intensity, duration and quality.  

Intensity, or brightness of the light, governs the manufacture of plant food, stem length, leaf color, and flowering.  Plants kept in low light rooms, as many offices are, tend to be spindly with leaves light green in color. In very bright light the plant would be stockier, with better branching and larger, dark green leaves.

Houseplants vary in their light needs: high, medium and low light. Control intensity of light by placing the plant closer to, or farther from, the light source, keeping in mind that light decreases rapidly as you move away from the source.

Southern windows have the most intense light, followed by eastern and western exposures.  Those receive about 60-percent of the intensity of south-facing windows, while northern exposures receive the lowest light levels of approximately 20-percent.

Duration of light received by plants is of some importance, but generally only to those houseplants that use day-length to stimulate bloom, such as Poinsettia, kalanchoe, and Christmas cactus.  Many flowering houseplants are indifferent to day-length; they respond to other factors so be sure to talk encouragingly with them. It may not inspire the plants to bloom but your co-workers will give you a wide berth; you’ll get plenty of projects done in that time.

  If you’re in a low light office, help your plant survive by increasing the length of time it gets artificial light.  This longer period of light during the day gives the plant more time to photosynthesize, producing food for itself. Comfort yourself with the knowledge that at least one thing in the office isn’t on a post-holiday diet.    

If artificial lights are to be used as the only source of light for growing plants, the quality of light (wavelength) must be considered. For photosynthesis, plants require mostly blues and reds but for flowering, infrared light is also needed. Fluorescent lights vary according to the phosphorus used by the manufacturer. Cool white lights produce mostly blue light and are low in red light. Foliage plants grow well under cool white fluorescent lights and these lights are cool enough to position quite close to plants. Blooming plants require extra infrared which can be supplied by incandescent lights or special horticultural type fluorescent lights.

However, plants require some period of darkness to grow; they should be illuminated for no more than 16 hours. Too much of a good thing is as harmful as too little.  Protect plants by turning off your lights as you leave for the day or put the lights on a timer.


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