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C.A. Conover, Ph.D., R.T. Poole, Ph.D. and K. Steinkamp*
University of Florida/IFAS
Central Florida Research and Education Center
CFREC-Apopka Research Report RH-94-5
Long lasting flowers, colorful foliage and adaptability to indoor conditions make bromeliads well suited for use in interiorscapes. Unfortunately, bromeliad foliage is sometimes damaged during shipping and handling. Damage is usually observed as a structural breakdown in tissue most often occurring near or at the arch in the leaf blade.
During previous research, Aechmea 'Friederike' plants were damaged during three days spent in dark 65°F coolers where relative humidity was 90% ± 10%. Plants were also damaged when watered just. three hours before being sleeved, boxed and placed in 65°F coolers for three days; however, two other species tested, Aechmea fasciata and Aechmea fasciata 'Morgana', were not damaged by the same simulated shipping treatments (Poole and Conover, 1992). In another test, Aechmea 'Friederike' fertilized at rates of 7.7 or 10.4 g nitrogen (N)/15-cm pot/yr, applied by means of a weekly 150 ml fertilizer solution, were not damaged during simulated shipping treatments (Poole and Henley, 1992).
Experiment 1 was conducted to further study effects of fertilizer rate and handling during shipping on growth and postharvest plant quality before and after simulated shipping. Experiment 2 was performed to determine effects of fertilizer N:K ratio on postproduction plant quality before and after simulated shipping.
Experiment 1 was initiated on June 26, 1992, when small Aechmea 'Friedericke' plantlets were potted into 15-cm (6-in) pots using Fafard #4 growing medium (Fafard, Inc. 3723 Hogshead Rd., Apopka FL 32703). Plants were grown to salable size in a greenhouse where maximum light intensity was 2000 ft-c and air temperatures ranged from 70 to 90°F. Plants were watered overhead when needed.
This was a 4 (nitrogen level) x 2 (shipping treatment) factorial experiment with five replications per treatment. Plants received 200, 300, 400 or 500 mg N, 14 mg P and 56 mg K in a 150 ml liquid fertilizer solution applied once a week (plants were fertilized at a rate of 5.2, 10.4, 15.6, or 20.8 g N, 0.73 g P and 2.9 g K/15-cm pot/yr). On January 26, 1993, plants were graded based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality.
After grading, one half of the plants in each fertilizer treatment were placed in standard 2-ft long 6-in wide (at the bottom) paper plant sleeves, boxed and moved to a dark 65°F cooler. The remaining plants, neither sleeved nor boxed, were placed on the floor of the same cooler. After plants had been in the cooler 24 hours, boxed and sleeved plants were unpacked. All plants were then moved back to the greenhouse. Number of damaged leaves per plant was counted on January 28, 1993.
In experiment 2, Aechmea 'Friedericke' were grown from small plantlets to salable size plants using fertilizer with various ratios of N to K. On February 10, 1993, plantlets were potted into 15-cm pots using Bacto Custom Blend growing medium (Michigan Peat Co., P.O. Box 980129, Houston, TX 77098). Plants were fertilized with 150 ml of a fertilizer solution once a week starting on March 1, 1993. Sixteen fertilizer treatments were tested (Table 3), with 6 replications per treatment.
Plant height, measured from growing medium to arch of highest leaf blade, was determined on September 17, 1993. On September 20, plants were graded (using the same scale as in experiment 1) then sleeved in paper plant sleeves, boxed and placed in 65°F dark coolers to simulate shipping conditions. On September 23, 1993, after three days in the simulated shipping environment, plants were unpacked and placed back in the greenhouse. On September 27, 1993, plants were graded based on the same scale as described above, number of damaged leaves was counted and damage was given a severity rating of 1 to 5 (1 = no damage, 2 = little visible damage, still salable, 3 = damage noticeable, but plants still salable, 4 = damage obvious, plants unsalable, 5 = damage severe).
Results
In experiment 1, plant grade decreased as fertilizer rate increased (Table 1). The lowest fertilizer rate, 5.2 g N/15-cm/yr, produced the best quality plants. Even though number of damaged leaves after simulated shipping was lower on plants fertilized at the low or high rates, differences were not great enough to affect plant salability. Plants placed on the floor of the cooler not sleeved and not boxed during simulated shipping had fewer damaged leaves compared to sleeved and boxed plants, but again, not much difference was seen in commercial value of the plants (Table 2).
In experiment 2, interaction of N:K fertilizer ratios slightly affected plant growth, quality and amount of foliage damage after shipping. However, as in experiment 1, not much difference was seen in commercial value of the plants when evaluated before and after simulated shipping (Tables 3 and 4). Plants getting the least or most fertilizer were shortest, and lowest quality plants were those getting fertilized at the highest N:K rate tested. Number of damaged leaves and severity of damage after simulated shipping was least on plants getting the two higher N levels combined with the 3.07 g K rate (Tables 5 and 6).
Conclusion
Overall results from these two tests and previous research suggest fertilizer rate and N:K ratio probably only play a small part in damage occurring during shipment of Aechmea 'Friederike'. Results of these tests indicate best fertilizer rate for 'Friederike' would be in the range of 4.0 to 5.0 g N and 3 g K/15-cm pot/yr. This N:K ratio is the same as the standard 31-2 N:P:K formulation that we have recommended previously (Conover and Poole, 1990). We continue to be concerned about the tissue collapse syndrome that occurs during shipping of bromeliads and plan to continue our research efforts in this area.
* Professor of Environmental Horticulture and Center Director (retired 7/96), Professor of Plant Physiology, and Technical Assistant, respectively, Central Florida Research and Education Center, 2807 Binion Road, Apopka, FL, 32703-8504.
References
- Conover, C.A. and R.T. Poole. 1990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. Nursery Digest 24(10):34-36, 58-59.
- Poole, R.T. and C.A. Conover. 1992. Reaction of three bromeliads to high humidity during storage. Univ. of Fla. CFREC-Apopka Res. Rpt. RH-92-26.
- Poole, R.T. and R.W. Henley. 1992. Response of bromeliads to fertilizer rate and shipping environment. Univ. of Fla. CFREC-Apopka Res. Rpt. RH-92-22.
Table 1. Effects of production nitrogen fertilizer level on plant grade before simulated shipping and on number of damaged leaves after simulated shipping (24 hours in a 65°F cooler) on Aechmea 'Friedericke' (Experiment 1).
| Fertilizer rate g/N/15-cm pot/yr |
Plant grade before shippingz |
Damaged leaves after shippingy |
|---|---|---|
| 5.2 | 4.2 | 1.3 |
| 10.4 | 3.4 | 2.3 |
| 15.6 | 3.2 | 2.2 |
| 20.8 | 2.5 | 1.5 |
| Significancex | ||
| linear | ** | ns |
| quadratic | ns | ** |
| cubic | * | ns |
zPlants were graded on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality on January 26, 1993.
yNumber of damaged leaves were counted on January 28, 1993, one day after simulated shipping treatments ended.
xns, *, **; Results nonsignificant, significant at P = 0.05 or P = 0.01, respectively.
Table 2. Number of damaged leaves on Aechmea 'Friedericke' plants sleeved and boxed during simulated shipping compared to number of damaged leaves on plants not sleeved and boxed during simulated shipping treatment (Experiment 1).
| Handling during simulated shippingz | Number of damaged leavesy |
|---|---|
| plants sleeved and boxed | 2.2a |
| plants not sleeved or boxed | 1.5b |
zPlants were sleeved in paper sleeves immediately before simulated shipping began on January 26, 1993. Sleeves were removed when plants were removed from coolers on January 27, 1993.
yNumber of damaged leaves per plant was counted on January 28, 1993, one day after simulated shipping ended.
Table 3. Height (cm) of Aechmea 'Friederike', affected by interaction of production NH4NO3 and KCL fertilization levelsz (Experiment 2).
| NH4NO3,
g/15-cm pot/year |
KCL, g/15-cm pot/year | |||
|---|---|---|---|---|
| 1.85 | 3.07 | 4.30 | 5.52 | |
| 1.85 | 33.7 | 36.3 | 37.2 | 37.7 |
| 3.07 | 37.3 | 36.3 | 34.8 | 37.2 |
| 4.30 | 38.5 | 38.2 | 35.8 | 34.8 |
| 5.52 | 35.2 | 34.8 | 37.7 | 33.7 |
Interaction results significant at P = 0.0367.
zPlants were grown from rooted plantlets to salable size before height was measured on September 17, 1993.
Table 4. Pre-shipment plant grade of Aechmea 'Friederike', affected by interaction of production NH4NO3 and KCL fertilization levelsz (Experiment 2).
| NH4NO3, g/15-cm pot/year |
KCL, g/15-cm pot/year | |||
|---|---|---|---|---|
| 1.85 | 3.07 | 4.30 | 5.52 | |
| 1.85 | 4.2 | 4.0 | 4.3 | 4.6 |
| 3.07 | 4.5 | 4.5 | 4.3 | 4.2 |
| 4.30 | 4.7 | 4.6 | 4.2 | 4.8 |
| 5.52 | 4.5 | 4.2 | 4.3 | 3.8 |
Interaction results significant at P = 0.0145.
zPlants were graded based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality, on September 20, 1993, one hour before shipping treatments began.
Table 5. Number of leaves on Aechmea 'Friederike' damaged during simulated shipping affected by interaction of NH4NO3 and KCL fertilization levelsz (Experiment 2).
| NH4NO3, g/15-cm pot/year |
KCL, g/15-cm pot/year | |||
|---|---|---|---|---|
| 1.85 | 3.07 | 4.30 | 5.52 | |
| 1.85 | 1.8 | 1.7 | 0.7 | 0.3 |
| 3.07 | 0.7 | 1.7 | 1.0 | 0.8 |
| 4.30 | 1.7 | 0.2 | 1.0 | 0.7 |
| 5.52 | 0.3 | 0.2 | 0.8 | 2.2 |
Interaction results significant at P = 0.0227.
zNumber of damaged leaves per pot was determined on September 27, 1993, one week after shipping treatments began, four days after plants were removed from coolers.
Table 6. Severity of damage occurring during simulated shipping on Aechmea 'Friederike' affected by interaction of production NH4NO3 and KCL fertilization levelsz (Experiment 2).
| NH4NO3, g/15-cm pot/year |
KCL, g/15-cm pot/year | |||
|---|---|---|---|---|
| 1.85 | 3.07 | 4.30 | 5.52 | |
| 1.85 | 2.6 | 2.2 | 1.6 | 1.4 |
| 3.07 | 1.8 | 2.4 | 2.2 | 1.5 |
| 4.30 | 1.9 | 1.2 | 1.9 | 1.5 |
| 5.52 | 1.4 | 1.1 | 1.8 | 3.1 |
Interaction results significant at P = 0.0224.
zSeverity of damage was determined based on a scale of 1 = no damage, 2 = little visible damage, still salable, 3 = damage noticeable but plants still salable, 4 = damage obvious, plants unsalable, 5 = damage severe. Severity of damage was determined on September 27, 1993, one week after shipping treatments began, four days after plants were removed from coolers.