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Steven E. Newman

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.

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Steven E. Newman

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.

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Andrea Crowell and Steven E. Newman

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.

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Muhammad Maqbool and Steven E. Newman

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.

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D. Clay Collins and Steven E. Newman

The Leaf Wetness Data Logger (LWL) and accompanying Logbook software were designed by Spectrum Technologies Inc. as a low-maintenance tool to aid in disease prediction and spray scheduling for outdoor field-grown crops. The LWL mimics leaf surface moisture represented as a value between 0 (dry) and 15 (wet). We explored an expanded use of the LWL to large-scale commercial greenhouses for the purpose of humidity control and disease prevention. Data were collected over 15 days in a commercial hydroponic tomato production greenhouse and repeated. Results indicated that leaf wetness, as determined by the LWL, increased during irrigation periods, with cumulative effects dependent on daily irrigation requirements and climate. Irrigation was controlled by the climate control computer in response to cumulative radiation intensity. By analyzing leaf wetness in correlation with climatic conditions, more adequate irrigation scheduling may be implemented, reducing the risk of disease spread and infection.

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Michael J. Roll and Steven E. Newman

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.

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C. Elizabeth Succop and Steven E. Newman

Fresh-market basil is becoming a viable greenhouse commodity in Colorado. Marketing pressures and profit advantages also encourage the production of certified organic produce. The research objectives were to determine the length of time basil plants were productive in the greenhouse and to compare the production of fresh-market basil grown with three root zone systems and two fertilizer treatments. The three systems were hydroponic rockwool slab culture, hydroponic perlite raised bed culture, and hydroponic peat/perlite/compost bag culture. The two types of hydroponic fertilizer treatments were an inorganically formulated nutrient solution and an organic solution consisting of fermented poultry compost, hydrolized fish emulsion, and soluble kelp. The plants were harvested once per week and fresh weight was determined. During the 2nd and 3rd months of harvest, productivity from the plants treated with the organic fertilizer was greatest in the perlite system. However, productivity from the plants treated with the traditional fertilizer was greatest in the bag mix and rockwool systems.

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Steven E. Newman* and Robert O. Miller

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%.

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Michael J. Roll and Steven E. Newman

Rooting of cuttings from three cultivars of Euphorbia pulcherrima Willd. was evaluated after regulating the photoperiod during the stock plant stage. One group of stock plants was exposed to a night break (4 hours) and another group was exposed to natural daylength during September. Cuttings harvested in late September from `Freedom Red' and `Monet' stock plants grown under the 4-hour night break rooted more rapidly and had greater root mass than `Freedom Red' and `Monet' grown under natural daylength, whereas rooting of cuttings from `V-17 Angelika Marble' was not influenced by the photoperiods tested. Using a night break to prevent flower initiation of stock plants produced a higher-quality cutting when propagation took place after the critical daylength for flowering had passed.

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Steven E. Newman' and Jesse R. Quarrels

The objective of this study was to determine the influence of uniconazole and calcium applied as a drench or foliar spray to `Gutbier V-14 Glory' poinsettias'. Uniconazole was drenched into half of the plants at 6 mg/pot. Calcium was applied weekly as either a spray, drench, or a combination of both at 350 ppm Ca. Uniconazole reduced plant height, bract dry weight, and plant dry weight. Bract dry weight from plants not treated with uniconazole and received calcium as a spray was less than from those plants that received either no supplemental calcium or calcium as a drench. Calcium improved the appearance of plants treated with uniconazole.