Results of a preliminary experiment using paclobutrazol at 0, 12 or 24 mg a.i./3.6-liter pot indicated that its use could enhance the appearance of pothos, but that some refinement of paclobutrazol rates should be made. Two experiments were conducted to determine the rate of paclobutrazol necessary to increase leaf size and optimize plant quality of pothos on totems in 3.6-liter pots grown under shadecloth providing 50% light penetration. In Experiment 1, rooted pothos cuttings were transplanted around a totem pole in a 3.6-liter pot and each pot was treated with a 250-ml drench of water containing Bonzi™ at 0, 4, 8, 12 or 16 mg a.i. Four mg a.i. of paclobutrazol yielded the most desirable plants, based on average leaf size, vine length and plant grade. Experiment 2 was designed to further refine the paclobutrazol application rate. Rooted cuttings of pothos were transplanted around a totem pole in a 3.6-liter pot and each pot was treated with a 100-ml drench of water containing paclobutrazol at 0, 1.32, 2.64, 3.96, 5.28, 6.60 or 7.92 mg a.i. Paclobutrazol applied at a rate of 5.28 mg a.i./3.6-liter pot optimized plant appearance by increasing leaf size and plant grade.
Maranta leuconeura Kerchoviana E. Morr. grew better at 15 than 21°C minimum night temperature (MNT), while Aglaonema commutation Schott. ‘Fransher’ and Aphelandra squar-rosa Nees. ‘Dania’ were unaffected by reduced MNT. Dieffenbachia maculata (Lodd.) G. Don ‘Marianne’ and Nephrolepis exaltata (L.) Schott. ‘Bostoniensis’ (Boston Fern) grew slightly better at 21 and 18° MNT while growth of Epipremnum aureum (Linden & Andre) Bunt (Golden Pothos) improved with each increase in MNT. Irrigation with 5,10,15 or 20° water had no effect on plant growth or grade.
Data indicated the N-P2O5-K2O ratio of 1-1-1 is unnecessarily high in P2O5 and K2O for Dieffenbachia maculata (Lodd.) G. Don ‘Exotica’, Dracaena sanderana Hort. Sander ex M. T. Mast, Maranta leuconeura var. kerchoviana E. Morr., and Peperomia obtusifolia (L.) A. Dietr. Plant growth and tissue nutrient levels were more sensitive to changes in N fertilization level than P and K. Tissue N was a more sensitive indicator of optimum growth and fertility practices than P or K.
Leaching of N into ground water has become a major pollutant in several areas of the U.S. The potential for regulation of environmental plant producers is increasing, but limited information is available on cultural management. This factorial experiment tested a liquid and a slow release fertilizer source at 3 irrigation levels (100, 200 or 300 ml/20 cm pot/2 times/wk) for NH4+, NO3- and P found in leachate collected weekly for 12 weeks. Plant quality and fresh weight for all treatments was similar, but large variations occurred in NH4+, NO3- and P levels in leachate due to irrigation level. Increasing irrigation level from 100 to 300 ml twice weekly resulted mainly in linear increases of NO3- present in leachate, with levels as high as 159 mg/l observed near the end of the production cycle. NH4+ levels were most affected by irrigation and highest early in the experiment, but were generally lower than 1 mg/l. P levels ranged from 1.4 to 16.0 mg/l in leachate with responses to fertilizer source and irrigation mainly during the first 6 weeks.
Brassaia actinophylla Endl. and Dieffenbachia maculata (Lodd.) G. Don ‘Perfection’ were grown under 0.5, 1.0 or 2.0 klx Cool White fluorescent light for 1 year in in anterior environment. Growth increased as light level increasede Increasing rate of fertilizer application from liquid or slow release fertilizer had no effect on growth at 0.5 klx, but a large effect at 2.0 klx. Influence of light and fertilizer levels on elemental tissue content is discussed.
Physical characteristics were determined for 5 potting media composed of varying ratios of Florida sedge peat and pine bark subjected to compaction pressures of 0.0, 0.1, 0.2, or 0.3 kg/cm2. Percent noncapillary pore space decreased as compaction pressure and amount of peat in the mixture increased, while water holding capacity by volume increased with peat addition and compaction pressure. Top growth of Pilea pubescens ‘Silver Tree’ in compacted media was generally as good as in noncompacted media, but root growth was restricted.
Six potting media (Metro Mix 200, 300, 350, 500, 2 sedge peatmoss : 1 pine bark : 1 cypress shavings (by volume) and 3 sedge peatmoss : 1 mason sand (v/v) were compacted at 0, 0.1, 0.2, or 0.3 kg·cm−2. Noncapillary pore space was reduced in all media at 0.1 kg·cm−2 as compared to 0 pressure, but increasing compaction pressure had more effect on 2:1:1 than on 3:1 or Metro Mixes. Pilea pubescens Liebm. ‘Silver Tree’ and Dracaena sanderana Hort. Sander ex M. T. Mast. were used in two additional experiments where the six media were combined factorially with compaction pressures of 0.1 and 0.2 kg·cm−2 and irrigation rates of two or four applications/week. Both genera were affected more by potting media and irrigation levels than by compaction, with best plants generally produced in Metro Mixes receiving the higher irrigation level.
Grade and vine length of P. oxycardium growing on totem poles increased as shade level decreased from 80 to 40%. Highest grade was obtained with Osmocote, followed by liquid fertilizer and MagAmp. Generally, 785 kg N/ha/3 months was adequate for good growth, although interactions occurred with light intensity as shown by lack of fertilizer response at high shade levels. Foliar N levels were higher in 80% shade but quality decreased. MagAmp increased P and Mg and decreased Ca and K levels in foliage, while Osmocote increased N.
Factorial experiments, including three potting media, two potting medium temperatures, and two air temperatures were used to evaluate growth of Nephrolepis exaltata ‘Fluffy Ruffle’ (Boston fern) infected with Rhizoctonia solani (the causal agent of aerial blight). Potting medium mixtures of sphagnum peat-sand, sphagnum peat-pine bark, and sphagnum peat-vermiculite-perlite did not affect severity (percentage of foliar infection) in four of five tests. Plant quality was highest for plants grown in peat-vermiculite-perlite in two of four tests. Potting medium temperature of 32°C reduced percentage of foliar infection in four of five tests, and plant quality in three of four tests. Fresh weights of shoots or roots were not affected consistently by potting medium temperature at 32°. Air temperatures ranging from 35° to 38° were favorable for disease development, with reduced development at temperatures above 35°. In vitro radial growth of R. solani isolates was optimal at ≈30° with a statistically significant reduction at 35°.
Leaf distortion of Aglaonema commutatum Schott ‘Fransher’ has been a common occurrence in commercial nurseries of Florida and elsewhere. New leaves arising from the apex were distorted, dwarfed and sometimes less than 4 cm long and 1 cm wide as opposed to normal leaves 20 cm long and 4 cm wide. Leaves sometimes had a slight curved, or hooked, appearance and edges rolled upward toward the center. Applications of copper (Cu) as a spray or drench reduced or eliminated leaf distortion.