Ornamental horticulture industries have the opportunity to utilize compost products as components in growing media, but heterogeneity among compost products can cause unpredictability in the activity of some growth regulators when applied as a drenches to the growing medium. These experiments evaluated the effect of 0%, 30%, 60%, or 100% compost (by volume) in the medium on the efficacy of paclobutrazol applied as a drench on Impatiens wallerana Hook. In experiment 1, paclobutrazol was applied at active ingredient (a.i.) drench rates of 0, 0.016, 0.032, 0.06, or 0.125 mg/pot 16 days after transplanting impatiens `Accent Red'. In experiment 2, paclobutrazol was applied at a.i. drench rates of 0, 0.25, 0.50, 1.0, or 2.0 mg/pot 14 days after transplanting impatiens `Dazzler Punch'. In both experiments, final height and size were reduced by paclobutrazol treatments compared to untreated plants. In experiment 1, shoot dry mass of treated plants was on the average of 0.92 g less than untreated plants, while shoot dry mass, in experiment 2, did not show a significant difference between treated and untreated plants. In both experiments, final height, size and shoot dry mass were significantly different among the media, with the greatest growth in 100% compost.
Growth of `Oasis Scarlet' begonia (Begonia ×semperflorens-cultorum Hort.) and `Super Elfin Violet' impatiens (Impatiens wallerana Hook. f.) was compared in substrates containing compost made from used greenhouse substrates and yard trimmings (GHC) and in compost made from biosolids and yard trimmings (SYT). Treatments consisted of 100% compost (GHC or SYT) or compost combined with control substrate components at 60%, 30%, or 0%. Substrates containing SYT compost produced significantly larger begonia and impatiens plants than substrates containing GHC compost. Higher initial substrate nutrient concentrations in substrates containing SYT probably prompted increased begonia and impatiens growth because substrates containing SYT compost had significantly higher initial soluble salt, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) concentrations than substrates containing GHC compost. Begonia and impatiens shoot dry mass and size linearly increased as the percentage of SYT compost in the substrate increased from 0% to 100%. However, no difference in begonia or impatiens growth was observed among the different percentages of GHC compost. Initial soluble salt, N, P, K, Ca, and Mg concentrations also linearly increased as the percentage of SYT increased while only initial P, K, and Ca concentrations linearly increased as the percentage of GHC increased.
Problems with iron toxicity are documented for the bedding plant species of geranium and marigold. It was suspected that observed nutrition problems of Chrysanthemum Xsuperbum `Snow Lady' were due to iron toxicity. The objectives of this study were to determine which if any perennial species were sensitive to iron toxicity (iron efficient) and to document any symptoms. Using a sand culture method, C. Xsuperbum `Snow Lady' and `Alaska', and Pelargonium Xhortorum `Red Elite' (as a check) and 3 other perennial species were watered twice daily with a modified Hoaglands I solution with 0.00, 0.02, 0.04, 0.08, 0.16, or 0.32 mM FeEDTA. Only Pelargonium had toxic foliar iron levels (462.2 ppm Fe averaged over all treatments) and showed classic iron toxicity symptoms. C. Xsuperbum `Alaska' showed possible iron toxicity symptoms at 0.08 and 0.16 mM FeEDTA with foliar iron levels of 301.0 ppm Fe and 282.7 ppm Fe, respectively. Below average foliar levels of Mn were observed in all species except Pelargonium. Also noted were: toxic levels of boron in Achillea and deficient levels of copper in Aguilegia.
Three bone products (meat and bone meal, steamed bone meal, and bone chips) were compared to a water-soluble P source (monocalcium phosphate) for P availability and enhancement of tomato shoot growth. All bone products were finely ground to pass through a 40-mesh sieve. The products were added to a phosphorus-deficient greenhouse growing medium based on their P concentration with P at 50, 100, 200, and 400 mg·kg−1. Meat and bone meal produced the least shoot growth in 1992, but all products were similar in 1993. Growth peaked with P at 111 mg·kg−1 in 1992, but in 1993, P at 50 mg·kg−1 was sufficient. Shoot P uptake was in direct proportion to P availability in the soil mix, monocalcium phosphate having the highest shoot P content. Although bone products affected N, Ca, Zn, and Mn content in shoots, the magnitudes of differences were minor and inconsistent from 1992 to 1993. Major consideration for using a bone product are its relative cost of P, fineness of grind, and CaCO3 equivalent.
Over the 10-year period of 1987-1997, the demographics of the student population enrolled in the University of Florida off-campus BS degree in horticulture program at Fort Lauderdale have changed. Average student age has increased from 35.5 years to 38.1 years. Age range has increased from 22 to 54 years to 21 to 75 years. Age distribution changes have been most notable. In 1987, the age of the student population was normally distributed, whereas by 1997 the distribution had become bimodal, with one mode in the age group 26 to 30 and the other mode in the 41 to 45 age group. Estimated median one-way distance traveled to attend classes has not changed significantly, from 13.2 miles (range 3.9-89.8 miles) in 1987 to 14.2 miles (range 1.0-59.8 miles) in 1997.
Analytical determination and confirmation of minimum compost processing times and minimum curing times can aid commercial growers in selecting compost materials that should give them more reliable and consistent results in their operations. Five-cubic-yard volumes of yard-trimmings were assembled into three 1.25-cubic-yard compost piles at 60-day intervals. At the conclusion of the experiment, there were three piles each of compost of the following ages: 10 months, 8 months, 6 months, and 2 months. Compost was collected from each pile and screened through a 0.75-inch screen. Bulk density, water-holding capacity, air-filled porosity, carbon to nitrogen ratio, electrical conductivity, and ATPase activity were determined on samples from each reference compost pile. A bioassay using beans also was performed. These data will be presented.
The average undergraduate horticulture major at the Univ. of Florida Academic Program at Fort Lauderdale is 38 years old. The older, non-traditional student population is quite diverse, but many individuals are motivated by a desire to change careers, and many of them have taken extensive academic course work at other institutions prior to applying for admission to the Univ. of Florida. Academic advisement of this type of student presents a substantial challenge because of the uncertainty of content and vigor of prior academic preparation. To help meet this challenge, we have developed several academic advisement checklists that indicate numbers and titles of critical preprofessional and general education courses from the academic institutions that have been most frequently attended by the highest numbers of the incoming non-traditional students. These checklists have been cross-referenced between the catalogs of the various academic institutions and the Univ. of Florida catalog. We use these documents to evaluate the academic preparation of incoming transfer students and to assist them in making correct course selections to remedy any academic deficiencies that could negatively influence their success in upper division horticulture course work.
Growth of hand-watered and subirrigated `Ultra Red' petunia (Petunia ×hybrida Hort.) and `Super Elfin Violet' impatiens (Impatiens wallerana Hook.f.) plants were compared when grown using four controlled-release fertilizer rates and four fertilizer placements in the pot. Furthermore, the amount of NO3-N leached from hand-watered plants was compared to amount captured by subirrigation system. Before planting, Osmocote (14N-6.2P-11.6K) (4 month release) was either topdressed (TD), layered in the middle of the pot (M), layered at the bottom of the pot (B), or incorporated throughout (I) the substrate at 1.25, 2.5, 5.0, or 7.5 kg·m-3 (oz/ft3). Shoot dry mass of petunia plants was similar between both irrigation systems and among the four fertilizer placements. Subirrigated petunias fertilized with 2.5 kg·m-3 had similar shoot dry mass as hand-watered petunias fertilized with 7.5 kg·m-3. Hand-watered impatiens had greater shoot dry mass than subirrigated impatiens. Hand-watered impatiens also had greater shoot dry mass in pots with fertilizer at TD, M, or I than with fertilizer at B, but no difference in growth was observed in subirrigated impatiens among the different fertilizer placements. Finally, significantly more NO3-N was leached from hand-watered plants than was captured with the subirrigation systems.
Areca palms [Dypsis lutescens (H. Wendl.) Beentje & J. Dransf.], spathiphyllums (Spathiphyllum Schott. `Figaro'), ixoras (Ixora L. `Nora Grant'), tomatoes (Lycopersicon esculentum Mill. `Floramerica'), marigolds (Tagetes erecta L. `Inca Gold'), bell peppers (Capsicum annuum L. `Better Bell'), and pentas [Pentas lanceolata (Forssk.) Deflers. `Cranberry'] were grown in a pine bark-based potting substrate and were fertilized weekly with 0, 8, 16, 32, or 64 mg (1.0 oz = 28,350 mg) of P per pot. Shoot, and to a much lesser extent, root dry weight, increased for all species as weekly P fertilization rate was increased from 0 to 8 mg/pot. As P fertilization was increased from 8 to 64 mg/pot, neither roots nor shoots of most species showed any additional growth in response to increased P. Root to shoot ratio decreased sharply as P fertilization rate was increased from 0 to 8 mg/pot, but remained relatively constant in response to further increases in P fertilization rate.
In this study, areca palm (Dypsis lutescens), crossandra (Crossandra infundibuliformis), pentas (Pentas lanceolat), and philodendron (Philodendron) `Hope' plants were transplanted into containers filled with four growing substrates and watered daily, every 2 days, or every 3 days using subirrigation or overhead irrigation. Plants were grown in either a pine bark/sedge peat/sand substrate (BSS), Metro-mix 500 (MM), Pro-mix GSX (PM), or a 60% biosolid substrate (SYT). For both irrigation systems, final shoot dry weight of pentas, crossandra, philodendron, and areca palm plants in each substrate was greatest for plants watered every day and least for plants watered every 3 days. At all three irrigation frequencies, pentas, crossandra, and philodendron shoot dry weight in subirrigated pots filled with PM was greater than in overhead watered pots filled with PM. PM had the highest total pore space and moisture content of the four substrates examined. There was no difference in pentas, crossandra, or philodendron shoot dry weight between the irrigation systems, at all three irrigation frequencies, when plants were grown in BSS, MM, or SYT. However, for all four substrates and at all three irrigation frequencies, areca palm shoot dry weight was greater in overhead watered pots than in subirrigated pots. The final substrate electrical conductivity (EC) in all four subirrigated palm substrates was more than double the concentrations in overhead watered palm substrates. In this study, largest pentas, crossandra, and philodendron plants were grown in pots filled with PM and subirrigated daily, while largest areca palm plants were grown in pots filled with MM or SYT and watered overhead daily.