ANNUAL REPORT, 1947-48 47 



Sufficient stock of the varieties has been retained by the Waltham Field Sta- 

 tion to perpetuate the strains. 



Insulation of Flower Shipping Boxes. (Harold E. White, Waltham.) In 

 October, 1947, a new plastic material was obtained Irom the Dow Chemical Com- 

 pany, Midland, Michigan, to determine its adaptability as an insulant for flower 

 shipping containers. This material was supplied in especially cut boards 1 inch 

 and H inch thick for liners to be fitted inside shipping boxes. The product, known 

 as Styrofoam, a plastic, multicellular foam produced by expanding polystyrine 

 40 times, is snow white in color. 



Styrofoam (Type 103.7) has a thermal conductivity K factor of 27-30, is 

 resistant to moisture, absorbing 6 percent or less by volume. Also it is resistant 

 to fire, burning at the rate of 7 to 8 inches per minute, has great structural 

 strength, and is very buoyant. A cubic foot weighs a maximum of 2 pounds. 

 At present Styrofoam is produced commercially for use in refrigeration plants,, 

 lockers, storage warehouses, and railroad cars. 



Cardboard shipping boxes 36 x 15x9 inches and 48 x 18 x 10 inches were lined 

 with Styrofoam boards. Other boxes were lined with 10 sheets of newspaper 

 covering the sides, ends, bottoms, and tops. Styrofoam-lined and newspaper- 

 lined boxes were wrapped with one sheet of manila paper. Two hundred car- 

 nation flowers were packed in each box. All boxes were placed outdoors with a 

 maximum exposure period of 18 hours. Hourly temperature readings withia 

 the boxes and on the outside were obtained by recording clock thermometers. 

 The lowest outside temperature recorded during the test was between 11° and 

 12°F. 



Experiments on the effect of low temperatures on cut flowers, conducted by 

 the U. S. Department of Agriculture, show that most flowers, including carna- 

 tions, are injured at a critical temperature of 28°F. or below. The shipping 

 boxes lined with 3^ inch Styrofoam boards dropped from an initial temperature 

 of 62°F. to 28°F. in a period of 6 hours, whereas the temperature in the news- 

 paper-lined box fell to 26°F. in 5 hours. The outside air temperature dropped tO' 

 12°F. The lowest temperature in the Styrofoam lined box was 26°F., and in the 

 newspaper lined box 24°F. 



Interior temperature of boxes lined with 1-inch Styrofoam dropped to 28°F. 

 in 8 hours, whereas the temperature in the newspaper-lined box fell to 28°F. in 

 4 hours. In these tests temperatures within boxes lined with newspapers dropped 

 more rapidly than in boxes prepared with Styrofoam. 



Styrofoam, as an insulant for flower-shipping containers, offers several desirable 

 features, such as lightness in weight and a low moisture factor; it is a sterile 

 medium and has a low thermal conductivity factor. It offers possibilities as an 

 insulation material against low temperatures and as a material to protect flowers- 

 from extreme heat during shipment. Its use presents some problems such as 

 production for this specialized field of use, the most satisfactory method of apply- 

 ing the lining to the boxes, and the cost of such an insulant as compared with 

 newspaper. 



Polyvinyl Resin Geon 31X Latex as a Flower Preservative. (Harold E. White,. 

 Waltham.) Geon 31X Latex is a water-dispersible resin which, when applied 

 to plant material or other objects, forms a thin transparent film. Materials can 

 be treated by dipping them in a solution of the Latex resin or they can be sprayed. 



Gardenias, carnations, camellias, cymbidium orchids, geraniums, and passion- 

 flowers were treated with 10, 20 and 30 percent solutions of the Latex. Pigmented 

 flowers, such as red, pink, or yellow, were affected unfavorably by even the 10^ 



