01/10/1991

Recycled Newspapers Useful in Greenhouse Production

AUBURN, Ala.—When does old news become new news? When its recycled.

That's the word from Ken Sanderson, a horticulturist working in the Alabama Agricultural Experiment Station at Auburn University. Sanderson's innovative use of old newspapers to simplify his greenhouse schedule made his weekends a little easier and won him a Green Thumbs Up award for environmental awareness.

Sanderson works primarily with small ornamental plants such as azaleas, mums, and poinsettias. These research plants require constant care, especially to ensure that they are properly watered. Because the watering system in Sanderson's greenhouse is not fully automated nor designed for the specific needs of his crops, watering had become a seven-day-a-week job for the researcher.

"I was looking for a way so I wouldn't have to water on Saturdays and Sundays and so I could make better use of my facilities," said Sanderson, who is a professor of horticulture at Auburn. "I had heard about people using old newspapers as capillary mats and I thought I'd try them."

Capillary mats are sheets of absorbent materials which are placed on the greenhouse benches under potted plants. The mat is watered and the plants draw water through the holes in the pot into the soil (or growth medium) to the roots. "Capillary mats can reduce water use and cut down on groundwater pollution," Sanderson explained. "And it's a lot faster to water the mats than it is to water each plant," he added.

Commercial capillary mats are made of a variety of substances from fiberglass to sand, but Sanderson needed an inexpensive alternative. He lined his greenhouse benches with black plastic, then layered about seven to 10 sheets of paper on top until the bench was covered. The potted plants were placed directly on the papers and then the paper was wetted.

"They're not very pretty, but they work. You can dump all the water on them that you want," he said, explaining that the plants take up only what they need. This allows Sanderson to water the mats thoroughly before a weekend and avoid having to visit the greenhouse every day.

Capillary mats are not just an alternative for nonautomated greenhouses. "This can work for any type of watering system," Sanderson said. "An automatic watering system which has drip or ooze tubes is usually used to wet the newspapers or a time clock can be added for total automation," he noted.

Sanderson found that the newspaper mats were not only affordable and effective, they had very few drawbacks. Mat gnats which often infest capillary mats have not been a problem in Sanderson's greenhouse. He has also found that algae growth, another common problem when mats are used, can be controlled by using a granular, controlled-release fertilizer on the plants rather than a liquid fertilizer.

The mats last about 10 weeks in the greenhouse, the normal length of time it takes to grow a crop. And, Sanderson has found, they can be recycled yet again. He gathers the wet newspapers along with any leaves or growth medium that might have collected on them and uses them in a compost pile or garden.

"I've heard stories about people finding old newspapers in dumps that were 20 years old and could still be read. They just don't break down very quickly," Sanderson said. "People have used old newspapers in the past as a mulch but at the end of the growing season you end up with newspapers, generally speaking, even if you put leaves on top. And you have to worry about the papers flying all over the neighborhood."

According to Sanderson, the newspapers from his greenhouse decompose very rapidly, offer a source of additional fertilizer to soil because of the greenhouse fertilizer that has collected in them, and are too wet to blow away.

Sanderson's work received acclaim from the McGreen Wisdom project, an educational program that promotes horticultural and ecological awareness and activities. He was among 25 individuals and companies honored with the Green Thumbs Up Award for exceptional efforts toward environmental education and stewardship.

So for Sanderson, old news is good news both in and out of the greenhouse.

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By:
Katie Smith