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University of Florida, IFAS,
Central Florida Research and Education Center - Apopka
CFREC-Apopka Research Report RH-92-12
R.T. Poole and C.A. Conover*
Dracaena fragrans 'Massangeana' (corn plant), are among the foliage plants most commonly found in commercial interiorscape designs; however, they seem to have more maintenance problems than other foliage plants installed in comparable settings (3, 5). Some industry experts indicate that the problems associated with corn plants may occur when plants are sold with root systems too small to physically support the tops, and are unable to utilize irrigation water fast enough to prevent over-watering when placed in interior environments (4).
Current recommendations on level of medium moisture at shipping time state that medium should be about 50 percent of container capacity (2). Some foliage plants are damaged by high production and shipping air temperatures (1, 6), making air temperature control a common factor during foliage plant production and shipping. However, in loading/shipping areas, where plants may be held for several hours prior to being shipped, air temperature may not be controlled. The following research was conducted to determine the influence of root development, medium moisture level and loading/shipping area air temperature during simulated shipping (storage).
Materials and Methods
This 3 x 2 x 2 factorial experiment, with 7 replications per treatment, was initiated on 13 June 1991, using 1 ft and 3 ft Dracaena fragrans 'Massangeana' cane growing in 10 inch containers, two (one of each length) per pot. Corn plants were grown in a medium composed of Florida sedge peat:pine bark:builders' sand (6:3: 1 by volume), amended with 7 lbs dolomite and 1 lb Micromax (Grace/Sierra Co., Milpitas, CA 95035)/yd3. Finished plants from this group were selected for study based on root ball development using a scale of 1 = 0 - 20% of root ball covered with healthy roots, 2 = 21 - 40% of root ball covered with healthy roots, 3 = 41 - 60% of root ball covered with healthy roots, 4 = 61- 80% of root ball covered with healthy roots and 5 = 81 - 100% of root ball covered with healthy roots. On 13 June 1991, plants were carefully removed from their containers, inspected and then quickly replaced after root grades were assigned to minimize medium/root ball disturbance. Only plants receiving root grades from 2.5 to 5.0 were used in the following test.
Corn plants were grouped into 3 categories according to root grades. Category 1 comprised plants with root grades of 2.5 - 3.0, category 2 included plants with root grades of 3.5 - 4.0 and, on category 3 plants, roots were assigned grades of 4.5 - 5.0. All categories were placed in a shadehouse under 70% shade where temperatures ranged from 70 to 95°F and overhead irrigation was performed 3 times/week. Growing medium was top-dressed with 10 g/10 inch pot 19-6-12 Osmocote (Grace/Sierra Co., Milpitas CA 95035) 3 month release rate fertilizer on 14 June 1991.
On 8 July 1991, half of the containerized plants included in this test were watered for the final time before loading and storage treatments started. Three days later, on 11 July 1991, when loading and storage began, medium in these pots was moderately moist, the level of moisture recommended when shipping foliage. The remaining plants were watered early in the morning on 11 July, so that medium in these pots was saturated but foliage had time to dry completely before plants were stored.
At 11:00 AM, on 11 July 1991, corn plants were moved from the shadehouse into rooms where air temperature was maintained at either 85 or 110°F. At 3:00 PM, after 4 hours in rooms, plants were placed in dark coolers, with no air exchange, maintained at 70°F to simulate a shipping environment.
After 4 days of storage, corn plants were returned to the shadehouse under 75% shade where air temperatures ranged from 70°F to 95°F. Plants were graded based on a quality scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality, salable and 5 = excellent quality plant material, on 4 September 1991.
Results and Discussion
All corn plants were determined to be of excellent quality when graded on 4 September 1991. Corn plant quality in this test was not influenced by root development, time of last watering before storage or air temperature during the 4 hours they spent in rooms. These results agree with previous research by us showing medium moisture and similar pre-shipment temperatures did not affect post-shipment plant quality grades of corn plants (7).
*Professor of Plant Physiology, and Center Director and Professor of Environmental Horticulture (retired 7/96), respectively, Central Florida Research and Education Center - Apopka, 2807 Binion Road, Apopka, FL 32703-8504.
1. Buck, L.T. and T.M Blessington. 1982. Postharvest effects of temperatures during simulated transit on quality factors of two Ficus species. HortScience 17:817-819.
2. Conover, C.A. and R.T. Poole. 1986. Shipping suggestions. Interior Landscape Industry 3(10):32-37.
3. Johnston, J. 1985. Handling mass cane. Interiorscape 4(4):18.
4. Hamilton, D.L. 1985. Foliage vs. roots. Interiorscape 4(5):34,41.
5. Morey, J., C. Morey and J. Johnston. 1987. The cane question: answered. Interiorscape 6(6):43-59.
6. Poole, R. T. and C. A. Conover. 1981. Influence of maximum air temperatures and irrigation frequencies during high temperature periods on growth of four foliage plants. HortScience 14:556-557.
7. Poole, R. T. and C. A. Conover. 1987. Effect of environmental factors on Dracaena 'Massangeana' during shipping. Proc. Fla. State Hort. Soc. 100:340-341.