Hypertext applications have grown from highlighted index referencing tools used in “help” windows to sophisticated file sharing between many computers linked via the World Wide Web (WWW). Software such as Mosaic makes this link easy and convenient by using “Hypertext Markup Language” (HTML). Most universities and many companies have installed WWW servers and have provided disk space for general use. Horticulture departments and many botanical gardens across the country and all over the world are adapting to this technology by providing access to extension information sheets, newsletters, and selected manuscripts. Pesticide chemical manufacturers are also establishing WWW servers with the intent on providing rapid access to pesticide labels and material safety data sheets (MSDS). For local classroom use, HTML using a WWW server can provide an innovative and alternative means for delivering lecture material.
Scaling from dissolved and suspended solids in irrigation water reduces the efficiency of greenhouse irrigation systems. Water deposits inside pipes reduce water flow and deposits may reduce the flow through irrigation emitters, often clogging them. If not properly maintained, the clogging of emitters requires constant maintenance. This results in considerable labor expense and/or emitter replacement. Scaling inside irrigation system pipes also has the potential to harbor plant pathogens from the resulting biofilms. Oxcide, a novel hypochlorous acid (HOCl) compound, is produced electrochemically by removing sodium and hydroxide from sodium hypochlorite. The elimination of sodium hydroxide from the product creates a nontoxic oxidizer. A system to inject Oxcide into irrigation water at a commercial Colorado greenhouse was installed to maintain irrigation efficiency of emitters and irrigation lines during Winter 2003. The oxidation reduction potential (ORP) was monitored and visual evaluations of irrigation equipment in the Oxcide treated zones compared to those zones not treated with Oxcide was conducted. During January through March, geranium stock plants were irrigated with water that maintained ORP levels at around 600 mV. Visual ratings of the irrigation emitters revealed that the injection of Oxcide in the irrigation water did reduce the level of deposition. Deposition on the main feed lines was so thick that they hindered the complete closure of existing valves. Treatment of the irrigation water Oxcide injection for six months successfully removed of the scale and deposits from the water line.
The rooting efficiency of cuttings from three poinsettia cultivars were evaluated after regulating the photoperiod during the stock plant stage. `Freedom Red', `Monet', and `V-17 Angelika Marble' stock plants were exposed to an extended photoperiod and to natural day length during September 1995. `Freedom Red' cuttings rooted more quickly under an extended photoperiod compared to those under natural day length. Furthermore, root dry weight from these cuttings was greater than cuttings from stock plants grown under natural day length. `Monet' cuttings also rooted more quickly when the stock plants were under an extended photoperiod, and showed similar differences in root weight as `Freedom Red'. Cuttings from `V-17 Angelika Marble' were not influenced by photoperiod. Lighting stock plants to block flower initiation produces a higher quality cutting when propagation takes place after the critical day length for flowering has passed.
During 1995, 33 poinsettia cultivars were evaluated for Colorado greenhouse production conditions. Plants were supplied by the Paul Ecke Poinsettia Ranch, Fischer Geraniums USA, Oglevee, and Mikkelsens. At the end of the production period, Colorado greenhouse growers were invited to an open house and asked to judge the cultivars for plant, bract, and cyathia quality. As rated by the 24 growers, the best red cultivars in overall performance were `Freedom Red', `Nutcracker Red', `Cortez', and `Bonita', respectively. The best pink cultivars in overall performance were `Nutcracker Pink', `Maren', and `Flirt', respectively. The best white cultivars in overall performance were `Nutcracker White' and `V-17 Angelika White', respectively. The best novelty cultivars in overall performance were `Puebla' and `Monet', respectively.
The cut-flower industry is continually searching for unique products to introduce to the floral industry. Our objective was to select potential species for trial as new greenhouse-grown alternative cut flowers. Hardy perennials from the Rock/Alpine Garden at the Denver Botanical Garden served as the selection pool. Plants in this collection were fitting due to their durability in Colorado conditions and their rugged unique beauty. Several trial cuts of potential species were taken, and the flowers were evaluated for flower size, stem length, stem strength, foliage, vase life, usefulness, and general aesthetic quality. Next, an informal survey of growers, retailers, researchers, and consumers was taken to determine which flowers had already been seen on the market and which flowers would be potentially successful in the trade. After assimilating the information, the following six species were selected for trial future greenhouse production: Anthyllis vulneraria, Dianthus giganteus, Diascia integerrima, Echium lusitanium, Heuchera sanguinea `Bressingham Hybrids', and Trollius yunnanensis.
An experiment was conducted to determine the influence of eight commercial root-zone media (four peat based and four pine bark based) on the effects of paclobutrazol applied to Euphorbia pulcherrima Willd. `Eckespoint Celebrate 2' as an impregnated spike or a drench. Paclobutrazol treatments had the least influence on stem elongation of poinsettias grown in the peat-based medium containing Bacctite, a compressed peat product designed to increase aeration and cation exchange capacity, or composted pine bark ground to a particle size that could pass through an opening 1 cm or smaller. Spikes were more effective at reducing shoot elongation than drenches. Spike treatments also resulted in lower bract dry-matter accumulation than drenches. Paclobutrazol applied as a spike to poinsettias at pinch could combine pinching and chemical growth regulator application into one simultaneous operation. Chemical name used: (±)-(R*,R*)-beta-[(4-chlorophenyl)methyl]-alpha-(1, 1,-dimethyl)-1H-1,2,4,-triazole-1-ethanol (paclobutrazol).
Greenhouse and nursery managers rely on testing laboratories with the expectations of accuracy and consistency. The Greenhouse and Nursery Media Analysis Proficiency (GNMAP) Testing program was initiated to provide laboratories servicing greenhouses and nurseries with inter-laboratory quality control. The GNMAP program operational guidelines are based on those outlined under ISO 9000, ISO/IEC Guide 43 and Draft ISO/IEC Guide 24, which describe the requirements for proficiency testing. Nine laboratories enrolled in the program in 2003 and submitted results for root zone media and fertilizer solutions. Data analysis provided the minimum, maximum and median values; median absolute deviation (MAD); overall reproducibility (Rd); individual reported lab values; repeatability (Rp) of lab value (CV for the individual lab); and mean lab value reported. The Rd was calculated from the median of all lab Rp values and is a measure of intra-lab variance. A measure of inter-lab variance was determined by calculating the relative median deviations (RMD = MAD/Median × 100). For one of the media distributed, results for the saturated media extract included median pH values from 4.3 to 6.9 with MAD values averaging 0.1 across the three samples. The electrical conductivity (EC) median values ranged from 0.36 to 4.57 dS/m with RMD averaging 31% of the median. The main variability between laboratories for the majority of the macro cations was closely aligned with measured EC. Cations (K, CA and Mg) concentrations ranged from 17 to 502 mg/L with Ca typically in the greatest concentration. Cation inter-lab precision, based on the RMD ranged from 9-32% across the three substrate samples. The greatest RMD was 31.8% for Ca and 9.2% for K. The Rd values for the cations averaged 5%.
Rice hulls, a by-product of the rice milling process, were used at various rates to substitute sphagnum peat moss in greenhouse media. Previous studies demonstrated that media containing rice hulls replacing the vermiculite fraction grew plants equal to or better than traditional peat vermiculite blends. The objective of this study was to determine if rice hulls can replace sphagnum peat moss in a greenhouse medium. Physical properties, including bulk density, total pore space, and water retention were determined in media blended with fresh or aged rice hulls, sphagnum peat moss, and vermiculite. The bulk density of the media increased with increasing levels of fresh rice hulls. The pore space in media containing both fresh and aged rice hulls decreased over time during the crop production cycle and the pH increased.
A leaching frame was constructed to detect residual plant growth regulators in media. The table was 0.9 × 1.8 m and designed to hold 40 10-cm diameter by 30-cm PVC cylinders. Each cylinder was cut lengthwise in half and resealed with duct tape. Rooted cuttings of `Freedom' poinsettias were planted into each cylinder using two media combinations: 2 vermiculite: 2 peat moss: 1 pine bark and 2 vermiculite: 1 peat moss: 2 pine bark (by volume). Four growth regulator treatments were applied to the medium two weeks after transplanting: control, 0.25 mg paclobutrazol, 0.25 mg uniconazole, and 0.125 mg paclobutrazol applied as spike. After plant growth was recorded, the cylinders were removed and sliced lengthwise. Snapdragon plugs were then transplanted into the medium along the length of the cylinder to determine if any residual paclobutrazol remained. Paclobutrazol and uniconazole reduced stem length. The presence of pine bark in the media reduced the effect of the plant growth regulators.
Twelve snapdragon cultivars of different response groups were grown in a double polyethylene greenhouse to determine the impact of no root-zone heat (RZH) and 22C RZH at 15 or 20C night air temperature (NT) on flower quality. Data were recorded when the first floret of each stem showed color and harvested when the lower third of the florets were open, Flower quality was evaluated at harvest based upon stem length and fresh weight using Society of American Florists standards. Cultivars `Butterfly White II', `Hercules', `Navajo', and West Virginia' (Group II) were the first to bloom under 20C NT regardless of RZH; whereas cultivars `Oklahoma', Houston', and `Potomac Pink' (Group IV) were delayed. Similar trends were observed under 15C NT, but the crop was harvested a few days earlier with RZH as compared to no heat. Flower quality was better under 15C NT.