Ornamentals

Hawaii Nursery Research

Edited by: Fred D. Rauch

Specialist in Horticulture, CTAHR, University of Hawaii.


Figures referred to in this document are unavailable at this time.

Comparison of Nutricote and Osmocote on Three Palm Species

Paul K. Murakami and Fred D. Rauch

Objective
The purpose of this trial was to compare one of the newer controlled-release fertilizers (Nutricote) with the current standard fertilizer product (Osmocote) for the production of three selected palm species.
Previous trials in Hawaii have shown that the use of Osmocote 18-6-12 resulted in better growth and quality compared to other controlled-release fertilizer products tested (Rauch 1989a; Rauch 1989b; Rauch et al. 1988). This experiment was initiated to evaluate the potential of this newer controlled-release fertilizer for the production of container-grown palms under Hawaii conditions.

Methods
Uniform, recently germinated seedlings of Chamaedorea seifrizii Burret, Chrysalidocarpus lutescens H. Wendl., and Phoenix roebelinii O'Brien were potted in 6-in (15-cm) plastic azalea pots in a 1:1 (v:v) peat:perlite mixture. The potting mix was amended with 2.5 kg/m3 of dolomite and 0.85 kg/m3 of Grace-Sierra Micromax.
Treatments consisted of Osmocote 18-6-12 (8-9 month release formulation) and Nutricote 20-7-10 (Type 270) (Shoji and Gandeza 1992) at equal rates of nitrogen. These were incorporated into the potting mix at 10 N rates (0, 0.1, 0.2, 0.4, 0.7, 1.1, 1.6, 2.2, 2.7, and 3.3 kg/m3). This trial was established in the UH-Manoa Magoon shade house under 73 percent shade in a randomized block design with 10 single-plant replicates. The plants were irrigated twice daily by overhead spray stakes, and the average temperature during the experiment period was 28.5/21.0 C (day/night).
Plant growth was measured as the height increase and the dry weight of plant tops at the conclusion of the experiment after eight months.

Results
Although the Osmocote-treated plants were slightly larger, the difference in plant height or dry weight of the tops of Chamaedorea seifrizii was not significant when the two controlled-release fertilizers were compared at equal rates of nitrogen (Fig. 1). Increasing rates of both fertilizers resulted in an increase in plant size, even at the highest N rate (3.3 kg/m3). The best N rate for optimum growth, without application of excessive amounts of fertilizer, was estimated to be 1.1 kg/m3, which is slightly higher than the middle rate recommended by the manufacturer. Plant quality was judged to be equal for the two fertilizers tested.
While the Nutricote-treated plants had slightly higher top dry weight, there was no significant difference in plant height or dry weight of the tops of Phoenix roebelinii when the two controlled-release fertilizers were compared at equal rates of nitrogen (Fig. 2). Again, there was an increase in plant growth with an increase in fertilizer rate, with the optimum N rate estimated to be about 1.1 kg/m3.
The growth of Chrysalidocarpus lutescens plants was identical when treated with the two controlled-release fertilizers at equal rates of nitrogen (Fig. 3). The optimum N rate for this palm was estimated to be about 1.1 kg/m3.
Based on the results of this trial it appears that Osmocote and Nutricote can be used with equal results in the production of quality palms at an optimum N rate of approximately 1.1 kg/m3.

References
Rauch, F. D. 1989a. Osmocote application trials with areca palm seedlings. Hawaii Nursery Research. Univ. of Hawaii, HITAHR Research Extension Series 103:11-12.

Rauch, F. D. 1989b. Nutrition of bamboo palm. 1988. Hawaii Nursery Research. Univ. of Hawaii, HITAHR Research Extension Series 103:14.

Rauch, F. D., P. Yahata, and P. K. Murakami. 1988. Influence of slow-release fertilizer on growth and quality of Chrysalidocarpus lutescens Wendl. J. Envir. Hort. 6(1):7-9.

Shoji, S., and A. T. Gandeza, eds. 1992. Controlled release fertilizers with polyolefin resin coating. Konno Printing Co., Ltd., Sendai, Japan.

Comparison of Nutricote and Osmocote under Production Conditions

Paul K. Murakami and Fred D. Rauch

Objective
The purpose of this trial was to evaluate Nutricote controlled-release fertilizer for the production of foliage plants under nursery production conditions. Previous trials under experimental conditions at the University of Hawaii demonstrated that Nutricote was promising for the production of quality palms in Hawaii (Murakami and Rauch 1995).

Methods
Uniform, 18-month-old Rhapis excelsa (Thunb.) A. Henry plants were potted into standard 8-inch (22-cm) plastic containers in a 1:4 (v:v) combination of a commercial mix (Blend 4) and screened 0.25-0.5 inch (0.6-1.3 cm) volcanic cinder. The potting mix was amended with 2.6 kg/m3 of dolomitic lime and 0.85 kg/m3 of Grace-Sierra Micromax. Treatments consisted of Osmocote 18-6-13 (a new formulation), Nutricote 20-7-10 (Type 270) (Shoji and Gandeza 1992), and the standard Osmocote 18-6-12 at equal rates of nitrogen. These materials were applied as a top dressing after planting, which was the current nursery practice, at 10 N rates (0, 0.3, 0.6, 1.3, 2.5, 3.8, 5.7, 7.6, 9.5, and 11.3 g per 8-inch container).
In addition, uniform eight-month-old Spathiphyllum 'Tasson' were potted into standard 8-inch plastic containers in a 1:2 (v:v) mixture of Blend 4 and medium perlite, amended as above. Treatments were Osmocote 18-6-13 and Nutricote 20-7-10 at the rates described above. This trial was established in a nursery in Waimanalo, Hawaii, in a randomized block design with 10 single-plant replicates. The plants were grown under 80 percent shade and watered daily by overhead sprinklers. Average daily temperatures were not recorded during the experiment period.
Growth measurements for rhapis were the plant height and the number of lateral breaks for the seedlings. Measurements on spathiphyllum were a growth index, [height + width]/2, and the number of flowers produced. These measurements were taken monthly. In addition, tissue samples were taken at the start and end of the experiment.

Results
Growth variables observed in this study showed few differences on a monthly basis, so the data were combined and evaluated. The two treatments with the Osmocote formulations resulted in better growth of Rhapis excelsa, as measured by plant height, than those treated with Nutricote (20-7-10) (Fig. 1). However, visual inspection showed that the plants treated with Nutricote appeared darker green than those treated with the Osmocote products at the end of the trial. The estimated optimum N fertilizer rate for this trial was 1 kg/m3. This rate is higher than the manufacturer's recommendation and the current grower practice.
There was no significant difference in the number of lateral shoots initiated at the base of the rhapis plants during this trial (Fig. 1). Although the difference was not statistically significant, there seemed to be a trend towards fewer breaks on plants treated with the new Osmocote formulation (18-6-13).
Results of the analysis of nutrient content in tissue of the most recently matured leaf of rhapis are shown in Figure 2. As expected, there was an increase in the nitrogen and potassium levels in the plant tissue with increased fertilizer rate. There was also a decrease in phosphorus levels. In general, there were higher levels of nitrogen and phosphorus in plants treated with Nutricote than in those treated with Osmocote, which might explain the darker green color of the plants in the Nutricote treatment.
Spathiphyllum 'Tasson' plants treated with Osmocote were larger than those fertilized with Nutricote at comparable nitrogen rates as determined from the growth index measurement (Fig. 3). However, as with rhapis palm, the Nutricote-treated plants were observed (no measurements were taken) to have a darker green color and broader leaves. The estimated optimum N application rate was determined to be 1.1 kg/m3.
Although the difference in flower production for spathiphyllum plants treated with the two fertilizers was not significant, there was a trend toward more flowers produced on the Osmocote-treated plants (Fig. 3). It was observed (not measured) that the Nutricote-treated plants produced larger flowers with greater substance.
As expected, there was a corresponding increase in the nutrient levels in the most recently matured leaf tissue of spathiphyllum with the increasing levels of applied fertilizers, with the exception of phosphorus in the leaves of the Nutricote-treated plants (Fig. 4). In all cases there was a greater rate of uptake in the Osmocote-treated plants than for those treated with Nutricote.
Fertilization of foliage plants with Osmocote resulted in slightly larger plants than those treated with Nutricote at the same rate of nitrogen under the conditions of this trial. However, the Nutricote-treated plants appeared to have slightly better quality.

References
Murakami, P. K., and F. D. Rauch. 1995. Comparison of Nutricote and Osmocote on three palm species. 1990-91 Hawaii Nursery Research. Univ. of Hawaii, HITAHR Research Extension Series 157 (this issue).

Shoji, S., and A. T. Gandeza, eds. 1992. Controlled release fertilizers with polyolefin resin coating. Konno Printing Co., Ltd., Sendai, Japan.

Comparison of Nutricote and Osmocote on Spathiphyllum

Paul M. Murakami and Fred D. Rauch

Objective
The purpose of this fertilizer trial was to compare Nutricote with the standard Osmocote formulation (18-6-12) for production of quality spathiphyllum under UH-Manoa shade house conditions.
Previous trials with spathiphyllum at a commercial nursery in Waimanalo showed that fertilization with Osmocote 18-6-12 resulted in better growth and flower-ing than Nutricote 20-7-10 (Type 270) (Murakami and Rauch 1995). The present trial evaluated Nutricote 18-6-8 (Type 270), because this formulation was thought to have a faster early release curve.

Methods
Uniform, one-year-old seedling plugs of Spathiphyllum 'Tasson' were potted in 5-inch (12-cm) plastic containers in a 1:1 (v:v) peat:perlite mixture. The potting mix was amended with 2.5 kg/m3 of dolomite and 0.85 kg/m3 of Grace-Sierra Micromax.
Treatments consisted of Osmocote 18-6-12 (8-9 month release formulation) and Nutricote 18-6-8 (Type 270) (Shoji and Gandeza 1992) at equal rates of nitrogen. These were applied at 10 N rates (0, 0.1, 0.2, 0.4, 0.7, 11.1, 1.6, 2.2, 2.7, and 3.3 kg/m3) incorporated into the potting mix. This trial was established in the UH-Manoa Magoon shade house under 73 percent shade in a randomized block design with 10 single plant replicates. The plants were irrigated twice daily by overhead spray stakes, and the average temperature for the experiment period was 28.5/21.0 C (day/night).
Plant growth was measured as the increase in plant height and width and the dry weight of the tops at the conclusion of the experiment after eight months. A volume measurement (growth index) was calculated using [height + width]/2.

Results
The response of spathiphyllum to increasing rates of applied N was an almost linear increase in growth as measured by the growth index and dry weight of the tops (Fig. 1). The plants treated with Nutricote grew at a faster rate than those treated with Osmocote. This was a reverse of the trends that were observed in the Waimanalo nursery trial (Murakami and Rauch 1995). This is perhaps due to the younger stage of the plant material in this trial, and the higher fertilizer levels required for optimum growth during periods of rapid growth. This trial demonstrates that the formulation of the fertilizer and its release rate influence the plant's growth response.

References
Murakami, P. K., and F. D. Rauch. 1995. Comparison of Nutricote and Osmocote under production conditions. 1990-91 Hawaii Nursery Research. Univ. of Hawaii, HITAHR Research Extension Series 157 (this issue).

Shoji, S., and A. T. Gandeza, eds. 1992. Controlled release fertilizers with polyolefin resin coating. Konno Printing Co., Ltd., Sendai, Japan.

Comparison of Nutricote and Osmocote on Chamaedorea elegans

Paul M. Murakami and Fred D. Rauch

Objective
This trial compared two formulations of Nutricote to the standard Osmocote fertilizer for the production of quality bamboo palm (Chamaedorea elegans). Because the bamboo palm is somewhat difficult to grow and is more fertilizer sensitive than other palm species, a second objective of this trial was to determine the optimum and excess fertilizer levels for its growth.

Methods
Uniform, eight-month-old seedlings of Chamaedorea elegans Mart. were potted three per 5-inch (12-cm) plastic container in a 1:1 (v:v) peat:perlite mixture. The potting mix was amended with 2.5 kg/m3 of dolomite and 0.85 kg/m3 of Grace-Sierra Micromax.
Treatments were Nutricote 20-7-10 (Type 270) (Shoji and Gandeza 1992), Nutricote 18-6-8 (Type 360), and Osmocote 18-6-12 to provide equal amounts of nitrogen. These were incorporated into the potting mix at 10 rates of N (0, 0.1, 0.2, 0.4, 0.7, 1.1, 1.6, 2.2, 2.7, and 3.3 kg/m3). This trial was established in the UH-Manoa Magoon shade house under 73 percent shade in a randomized block design with 10 single-pot replicates. The plants were irrigated twice daily by overhead spray stakes, and the average temperature for the experiment period was 28.5/21.0 C (day/night).
Plant growth was measured as the increase in plant height and width and the dry weight of the tops at the conclusion of the experiment after seven months. A volume measurement (growth index) was calculated using [height + width]/2. In addition, the pH and nitrate nitrogen content of collected container leachate was monitored on a monthly basis with an Orion model 230 pH/Mev meter with a nitrate electrode (Orion 93-07) and a model 230A pH meter (Wright 1986).

Results
The initial response to greater fertilizer rates was an increase in growth as measured by growth index and top dry weight (Fig. 1). As the fertilizer rate was further increased, there was a leveling-off of growth, indicating luxury consumption, and finally a reduction in growth at the highest fertilizer rate. The optimum fertilizer nitrogen rate for the production of quality Chamaedorea elegans was estimated to be about 2.2 kg/m3. Fertilizing with Osmocote resulted in larger plants compared to fertilizing with Nutricote.
The pH measurements of the leachate from this experiment indicated that controlled-release fertilizers alter the pH of the medium over time (Table 1). When the lower rates of the three fertilizers were used, there appeared to be a slight increase in the pH readings until about the third or fourth month, followed by a return to the original pH by the end of the trial at seven months.
The trend was the opposite with the higher fertilizer levels. There was marked decrease in the pH readings until about the third or fourth month, followed by a return to the original level by the end of the trial. The Osmocote treatments resulted in a greater pH depression than either of the Nutricote products, down to almost pH 4.0 at the highest rates. However, there did not seem to be any correlation between this pH change and growth of the plants.
Nitrate leachate readings were highly variable (data not shown). In most cases the amount of leachate recorded with the leachate collection method (Wright 1986) did not show high release of nitrate nitrogen over time. Even at excessively high fertilization rates, the results did not show large nitrate losses due to leaching in this experiment (losses were in the 100-150 ppm range). It was observed that there was a slightly higher nitrate loss from the Osmocote treatments, in the second through fourth months, than from the Nutricote-treated plants. The Nutricote treatments showed a steady nitrate release until about the sixth month, followed by a quick drop-off. The drop-off for Osmocote occurred in the fifth month.
The results suggested that either Osmocote or Nutricote can be used to produce quality Chamaedorea elegans, with a slightly better response from Osmocote. This may be due to a slightly higher release of nitrate nitrogen in the early months from the Osmocote fertilizer.

References
Shoji, S., and A. T. Gandeza, eds. 1992. Controlled release fertilizers with polyolefin resin coating. Konno Printing Co., Ltd., Sendai, Japan.
Wright, R. D. 1986. The pour-through nutrient extraction procedure. HortScience 21:227-229.


Table 1. The influence of three fertilizers on pH of leachate from pots of Chamaedorea elegans over seven months (pH values are of five pooled samples).

Fertilizer: Nutricote 20-7-10 (Type 270)
N level applied (kg/m3)

Fertilizer: Nutricote 20-7-10 (Type 360)
N level applied (kg/m3)

Fertilizer: Osmocote 18-6-12
N level applied (kg/m3)

- Data unavailable.

Comparison of Nutricote and Osmocote on New Guinea Impatiens

Paul M. Murakami and Fred D. Rauch

Objective
The objective of this trial was to determine the optimum and excess levels of Nutricote 13-13-13 fertilizer for the production of quality short-term potted plants.
New Guinea impatiens was selected as the test plant because it has been reported to be fertilizer-sensitive. An Osmocote product (14-14-14) was selected for comparison purposes.

Methods
Uniform, six-week-old, rooted impatiens cuttings were potted into 6-inch (15-cm) plastic containers in a 1:1 (v:v) peat:perlite mixture. The potting mix was amended with 2.5 kg/m3 of dolomite and 0.85 kg/m3 of Grace-Sierra Micromax.
These trials were established in the UH-Manoa Magoon shade house under 30 percent shade in a randomized block design with 10 single-plant replicates. Treatments consisted of Nutricote 13-13-13 (Type 100) (Shoji and Gandeza 1992) compared to the standard Osmocote 14-14-14 formulation at equal rates of nitrogen. The plants were irrigated twice daily by overhead spray stakes, and the average temperature for the experiment period was 28.5/21.0 C (day/night).
Plant growth was measured as the increase in plant height and width and the dry weight of the tops at the conclusion of the experiment after seven months. A volume measurement (growth index) was calculated using [height + width]/2.
Experiment 1. The test plants in this trial were two New Guinea impatiens cultivars, Impatiens 'Spectrum Rose' and Impatiens 'Spectrum Pink'. The two fertilizers were applied at five N rates (0, 0.3, 0.6, 0.8, and 1.1 kg/m3) incorporated into the potting mix.
Experiment 2. The test plant in this trial was Impatiens 'Spectrum Rose'. The two fertilizers were applied at five N rates (0, 0.6, 1.1, 1.7, and 3.0 kg/m3) incorporated into the potting mix.

Results
Experiment 1. There was a linear increase in the plant response with an increase in the fertilizer rate for both fertilizers and both cultivars (Fig. 1, 2). Comparing the growth of Impatiens 'Spectrum Rose', as measured by top dry weight and growth index, there was no difference between the two fertilizer sources. However, the growth rate of Impatiens 'Spectrum Pink' was enhanced slightly with Nutricote compared to the Osmocote fertilizer. The flowering response was inconsistent, being opposite for the two impatiens cultivars.
While it is clear that the growth and flowering were influenced by the fertilizers used and their rates, we were not able to reach the optimum fertilizer level for this plant. A second trial was initiated to evaluate these fertilizers at higher rates.
Experiment 2. Even at these higher fertilizer rates (up to five times the recommended rate), we did not reach a level that caused injury or reduced growth (Fig. 3). However, there was a leveling off of the growth rate with the higher fertilizer levels, suggesting luxury consumption. It is estimated from these results that the optimum fertilizer rate is about 1.1 kg/m3 of nitrogen.
The plants treated with Nutricote fertilizer were slightly larger and produced more flowers than those treated with Osmocote. This agrees with the first impatiens trial. However, these differences do not appear to be significant.
These results suggest that to obtain the optimum growth rate for the production of quality impatiens under our conditions, the fertilizer rate for both Osmocote and Nutricote should be increased above that recommended by the manufacturer. It also appears that both of these products will give satisfactory results, although Nutricote may produce slightly better production, as suggested by our results.

References
Shoji, S., and A. T. Gandeza, eds. 1992. Controlled release fertilizers with polyolefin resin coating. Konno Printing Co., Ltd., Sendai, Japan.