Effects of glass and fiberglass on carnation growth
Date
1961
Authors
Briggs, Robert A., author
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Abstract
Glass has been used for a greenhouse covering for as long as greenhouses have been built. The growers in these greenhouses have been uneasy about using new materials. When fiberglass plastic was introduced on the market a few years ago, the general conception was that this material reduced the amount of light that the plants would receive, therefore limiting plant growth. But in the last two or three years the interest in this plastic has become more ardent. Research on fiberglass was at a minimum, therefore a project was started to compare fiberglass to glass. The effects on carnation growth of glass, mylar, eskay-lite, velon screen, and 7 colors of Filon 180 corrugated fiberglass paneling in the colors of clear white, frost white, coral, jade, amber, yellow, and a special light purple were measured by young plants grown from June to August, 1959. The clear and coral fiberglass increased growth over glass by 18 and 15 percent, respectively. Three houses were constructed from wood with clear and coral fiberglass coverings, and greenhouse glass. The approximate dimensions were 18 by 15 feet, each house was a complete system with forced air heaters, and air conditioning. They were maintained at the same temperature: 52° F at night, heat to 60° F in day and cool at 65° F. The four varieties of carnations used in this experiment were Red Sim, Pink Mamie, Pikes Peak Frosted and White Sim. They were planted on January 3, 1960, and grown for this experiment until April 1, 1961. Due to gas injury caused by the heating system the results of yield and quality for the coral house and after November 5, 1960, for the clear and glass houses were not included. The flowers were harvested from these houses four times a week. They were graded with the fresh weight of the fancy and standard flowers recorded. Periodic random samples were taken to measure cut flower keeping life, flower volume, and flower color. The clear fiberglass increased yield by 12 percent while significantly improving mean grade. Cut flower keeping life and volume of the cut flowers were the same in all three structures, but flower color was improved by the fiberglass materials. The production of dry matter by young carnation plants over a nine week period was measured. The glass house produced more dry matter which was attributed to higher plant temperature. The solar energy and heat was measured in several ways. The following is some information from these measurements: 1. Clear fiberglass transmitted 12 percent less solar energy than glass when measured by an Epply pyrheliometer. 2. Clear fiberglass reduced energy transmission in the Visible and infra-red regions of the spectrum to 96 percent and coral fiberglass to 83 percent of that coming through glass. 3. The energy transmission in the ultra-violet and visible regions of the spectrum by clear fiberglass was 96 percent and by coral 58 percent of glass. 4. Light transmission from a 6-volt tungsten lamp was 84 percent for glass, 36 percent for clear, and 30 percent for coral. 5. Excess solar heat in the glass house above that required to maintain a 65° F day temperature was 65 percent greater than that in the coral house and 26 percent greater than that in the clear house.
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Subject
Carnations
Growth (Plants)
Plants -- Effect of light on