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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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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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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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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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Allen D. Owings and Steven E. Newman

Four rates of seven plant growth regulators were foliar-applied to 11.4 liter containers of Photinia × fraseri after initial root establishment. Growth regulators studied were uniconazole, paclobutrazol, dikegulac-sodium, ancymidol, 6-BA, GA4+7 and, 6-BA + GA4+7. Six months after application, plant height, plant width, growth index, and number of lateral and terminal branches were recorded.

Applications of uniconazole (30 mg a.i./liter), 6-BA alone or in combination with GA4+7, and dikegulacsodium stimulated lateral branching. The number of lateral branches increased linearly as paclobutrazol rates increased from 60 to 180 mg a.i./liter. Growth index decreased with increasing application rates of uniconazole and paclobutrazol, while the growth index of photinia treated with other growth regulators wasn't affected by application rate. Plant height was increased in GA4+7 treated plants.

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Allen D. Owings and Steven E. Newman

The action of foliar-applied uniconazole, paclobutrazol, dikegulac-sodium, ancymidol, 6-BA, GA4+7, and 6-BA + GA4+7 On container–grown Photinia × fraseri was studied over a one year period. Vegetative growth habit was evaluated at three month intervals. Shoot dry weight and histological examination of stern anatomy in the apical meristematic region was conducted at experiment termination.

Several plant growth regulators, primarily uniconazole, 6-BA, 6-BA + GA4+7, and dikegulac-sodium, stimulated lateral branching. Linear increases in lateral branching occurred as application rates increased. High application rates of uniconazole and paclobutrazol created an asymmetrical growth habit and decreased dry weight accumulation.

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Shelly D. Dueitt and Steven E. Newman

Rice hulls, a by-product of rice milling, were used at various rates in greenhouse media. The objective of this study was to determine if rice hulls can replace peat moss. Hulls, aged and fresh, were blended with vermiculite and peat moss from 0 to 50%, by volume replacing peat moss. Physical and chemical properties including bulk density, total pore space, water retention, pH and soluble salt concentrations were determined in the media blends. Marigolds and salvia were transplanted into 13 cm azalea pots containing each media. The bulk density increased with increasing levels of hulls. Total pore space of the media before planting was decreased with increasing levels of aged hulls, but no differences were detected at the termination of the study. Water retention of both fresh and aged hulls at all levels of media were equivalent to the control media. Before planting, the total soluble salts for media containing fresh hulls was greater than with aged hulls. The pH of the media increased with increasing levels of hulls, fresh and aged. The greatest dry weight and plant height was observed when the media contained 10 to 20% aged hulls.

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Jesse R Quarrels and Steven E. Newman

A study was conducted to determine the effects of pine bark grind size and pine bark levels on the activity of two growth regulators on poinsettia Two bark grinds (≤ 6 mm and >10 mm) were used with four media combinations within each grind: vermiculite:bark:peat moss at 2:0:3, 2:1:2, 2:2:1, and 2:3:0 (by volume). Two growth regulators, paclobutrazol and uniconazole, were applied at 0, 0.125, and 0.250 mg/15 cm container in 250 ml water. Two poinsettia cultivars, `Freedom' and `Gutbier V-14 Glory', were planted September 2, 1993, pinched September 16, and growth regulators applied September 30. There were five single plant replications for each treatment. Stem length and bract area were effected by bark grind, bark level, growth regulator, and growth regulator rate. Plants treated with uniconazole had the shortest stems and the least bract area. Plants grown in the smaller grind and at higher bark levels were less effected. Plants treated with paclobutrazol had longer stems than those treated with uniconazole.

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Khin San Wai and Steven E. Newman

Growth chamber studies using elevated root-zone temperatures and greenhouse studies using two root-zone and two night air temperatures were conducted to determine the effects on growth and flowering of two response groups [`Rainier White' (Group II) and `Tampico' (Group III)] of cut-flower snapdragons (Antirrhinum majus L.). Chamber-grown snapdragons with the root zone at 30C had shorter stems and a lower dry weight than those at 20C. Holding the root zone above 26C increased time to flower. Greenhouse-grown `Tampico' and `Rainier White' snapdragon stems were longer with increased root-zone temperature regardless of night air temperature. Time to flower was reduced an average of 6 days with increased root-zone temperature and 12 days when the night air was maintained at 20C. This study demonstrated that the effects of relatively low greenhouse temperatures may be offset by root-zone heat.

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Jesse R. Quarrels and Steven E. Newman

Greenhouse studies of cut flower snapdragons (Antirrhinum majus L.) using two night air and two root-zone temperatures were conducted to determine the effects on growth and quality of four cultivars in two response groups [`Cheyenne' and `Rainier White' (group II) and `Tampico' and `Potomac' (group III)]. The group II cultivars were the earliest to harvest, but at the expense of quality. Grades of first, extra, and fancy only were harvested. Group III cultivars were harvested with all grades; first, extra, fancy and special. Group II cultivars generally had weaker stems and were of lower dry weight. Night air temperature had the greatest effect on days to harvest. Harvest date was reduced more than 14 days, but at the expense of quality and dry weight. Root-zone heating decreased quality of the group II cultivars at either night air temperature. but reduced quality of the group Ill cultivars only at high night temperatures. Root-zone heat and high night air temperature reduced the number of days to harvest, also at the expense of quality. The majority of high quality stems were from group Ill cultivars harvested from rooms with low night temperatures without root-zone heat.