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  • Author or Editor: Richard Harkess x
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An experiment was conducted to determine the effect of earthworm (Eisenia fetida andrei) castings derived from sheep, cow, or horse manures on the growth of poinsettia (Euphorbia pulcherrima `Freedom Red'). Poinsettia cuttings were transplanted to 1-L (15-cm-diameter) plastic pots that were filled with castings:peat moss at 1:0, 1:3, 1:1, 3:1, or 0:1 by volume for each animal manure evaluated. Plants were fertilized using 200 ppm N from a 15-5-25 (N-P2O5-K2O) fertilizer applied with the irrigation water. Total bract area and growth index were greatest in those treatments consisting of 3:1 and 1:1 (castings:peat) from sheep and cow manures, 1:0 (castings:peat) from cow manure and for growth index only, 1:0 (castings:peat) from horse manure. For these two characteristics, 100% sheep manure castings and 100% peatmoss had the lowest values. The time to anthesis was least when poinsettias were grown in 3:1 or 1:1 castings:peat from sheep and cow manures and 1:3, 1:0, or 3:1 from sheep, cow, or horse manure respectively. Anthesis was most delayed when plants were grown in 100% castings from sheep manure.

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Experiments were conducted to evaluate earthworm castings (vermicompost) as a substrate for poinsettia (Euphorbia pulcherrima Willd.) `Freedom Red' production. Vermicomposts produced from sheep, cattle, or horse manures were mixed at different ratios with 70 peatmoss: 30 perlite (v/v) to create 13 substrates. Chemical and physical properties were measured on all substrates used. Growth index, foliar and bract area, and dry weight were greater on plants grown in substrates with castings from sheep or cattle manure. These castings had greater initial nutrient content than the castings from horse manure. Mixtures of castings and peat produced better plant responses than castings alone. Better plant responses were sometimes associated with values outside the recommended pH and electrical conductivity levels for poinsettia production. The highest values obtained for growth index, foliar and bract area, dry weight, and root development were produced in the substrates with moderate pore space or water holding capacity. Substrates with greater air space produced plants with greater dry weight and root development than substrates with less air space. The highest quality plants were grown in substrates with 25% castings from sheep or cattle manures.

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Earthworm castings (vermicompost) were evaluated as a substrate amendment for chrysanthemum [Dendranthema ×grandiflora (Ramat.) Kitam.] `Miramar' production. Vermicompost produced from sheep, cattle, and horse manures were mixed at different ratios with 70 peatmoss: 30 perlite (v/v) to create 12 substrates. The 70 peatmoss: 30 perlite mix at 100% and Sunshine® Mix 1 were used as control substrates. The bulk density, percentage of pore space, and water holding capacity increased as vermicompost content increased while the percentage of air space decreased. At 100% vermicompost, water holding capacity and bulk density were greatest in vermicompost from sheep manure. Plants grown in mixtures of 50% vermicompost from sheep had a greater growth index at harvest, foliar area, number of flowers per pot, and dry weight and fewer days for flower development than plants grown in other substrates. Vermicompost from sheep manure added at 50% by volume was most effective as a substrate amendment for chrysanthemum production.

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Geranium (Pelargonium ×hortorum L.H. Bailey) `Freckles' and poinsettia (Euphorbia pulcherrima Willd. ex Klotzch) `Freedom' were grown in six peat and shredded-rubber substrates formulated to contain 75:25:0, 50:50:0, 25:75:0, 75:0:25, 50:0:50, 25:0:75 sphagnum peat: fine-grade rubber: coarse-grade rubber (by volume). Additionally, plants were grown in a 50 peat: 30 perlite: 20 loam (by volume) control substrate. Shredded rubber-containing substrates had higher bulk densities, lower total pore space, and higher total solids than the control substrate. Fine rubber-containing substrates had lower air-filled pore space (AFP) and lower water-holding capacities (WHC) than the control substrate. Substrates containing 25% coarse rubber had lower AFP and WHC than the control, but substrates containing 50% and 75% coarse shredded rubber had higher AFP and lower WHC than the control. Shredded rubber-containing substrates had significantly higher levels of Zn than the control substrate. Plants grown in rubber-containing substrates had tissue Zn levels significantly higher than the control and at levels reported to be phytotoxic in other species. Geraniums grown in rubber-containing substrates had lower root and shoot fresh mass, were shorter, and had fewer axillary branches than those grown in the control substrate. Poinsettia plants grown in rubber-containing substrates were shorter, had lower shoot fresh mass, fewer bracts, and lower bract area as compared to plants grown in the control substrate.

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On 2 Feb. 1996, rooted cuttings of Pelargonium × hortorum L. H. Bailey cvs. Tango and Blues were planted in 750-cm3 (14 cm in diameter) pots containing peatmoss mixed with shredded tire rubber (2–6.0 mm particle size) at 0%, 20%, 40%, 60%, or 80%. Plants were irrigated by hand, drip, or ebb-and-fl ood, and were arranged in a split-plot experimental design. A wetting agent (Aqua Gro 2000 L, Aquatrols Corporation, Cherry Hill, N.J.) was mixed at the rate of 6 ml per 3750 ml of water and 120 ml of solution was applied to each plant. Greenhouse studies indicated that geraniums could be grown successfully in media containing up to 20% shredded tire rubber by volume when irrigated by hand. Plants grown in media containing more than 20% rubber were observed to be slow-growing and chlorotic. Tissue analysis of the plants indicated significantly increased levels of zinc in plants grown in media containing high percentages of rubber. Geraniums grown in media containing 80% rubber and irrigated using ebb-and-fl ood benches had the significantly highest levels of foliar zinc. Media porosity, percent air space, and bulk density increased, while water holding capacity decreased with increasing amounts of shredded tire rubber added to the media.

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The Transplanted Floral Meadow is a culture technique designed to provide an herbaceous planting of continuous seasonal bloom beginning about 1 month after transplanting to the landscape. The technique requires little or no maintenance once the plants have become established. The meadow consists of a seed mix of annual flowers that are started in the greenhouse in mixed plugs and transplanted to the landscape. In this study, plugs of the annual transplanted floral meadow seed mix were started by broadcasting the seed mix over flats of standard nursery cell-packs filled with a commercial growing medium. The plugs were grown in the greenhouse and transplanted to plots 4 weeks after sowing at 30 × 30-, 30 × 45-, or 30 × 60-cm spacing. The plug sizes used were 801, 1801, 804, or 1804 cell-packs. The plugs were transplanted to 2.25-m2 plots with three replications, each plot being a replication. Plug size and spacing were evaluated based on the rate of canopy closure measured biweekly as the amount of photosynthetically active radiation penetrating the canopy. Close transplant spacing with large plug sizes provided the quickest site coverage. The 1801 and 801 plug sizes provided the greatest species diversity. The 1804 plug size reduced the number of seedlings present at the time of transplanting and did not cover the site until late in the season. The 801 and 1801 plug sizes at 30 × 30or 30 × 45-cm spacing resulted in the best floral display. The results of this research will be used to standardize the transplanted floral meadow technique for use as a new product in the nursery trade.

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Maintaining annual color throughout the long summer season in warm temperate regions has become an interest to landscapers and nursery operators. Some colorscaping companies have begun implementing a second summer planting season. There is little information available concerning suitable cultivars and species of bedding plants for establishment in late summer. This study examined plant establishment in two container sizes and three dates of transplanting to determine late season establishment in Starkville, Miss. (33°27' latitude, 88°49' longitude). Seeds of 27 different cultivars were grown in plug flats in the greenhouse and transplanted into jumbo 606 or 10-cm square containers. The plants were grown in the greenhouse until transplanting on 16 Aug., 30 Aug., or 13 Sept. 1996. The plants were transplanted into plots containing nine plants with three replications per planting date. The plants were spaced on 20-cm centers among and between plots. The earliest two plantings resulted in better plant establishment and floral display. Some of the cultivars and species were more tolerant of the late season temperature and humidity establishing and providing a good color display from 6 weeks after transplanting until frost, 2 Nov. 1996. Cultivars that performed well included: Impatiens wallerana `Deco Crystal', `Expo Lavender Blush', `Dazzler Salmon', Begonia semperflorens `Varsity Bronze Scarlet', Zinnia `White Pinwheel', Tagetes erecta `Marvel Gold', and Tagetes patula `Bonanza Harmony'. Cultivars that did not establish well under these conditions included: Verbena hybrida `Romance Pink' and Salvia splendens `Salsa Salmon'. The container size did not significantly affect plant establishment.

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Lagerstroemia has potential for development as a potted florist crop for early spring sales. The number and timing of pinching or number of liners per container were examined as a means of developing a more compact plant that is in proportion to the container. On 20 July 1996, either one or three rooted liners of Lagerstroemia `Victor' or `Zuni' were planted into 1500-ml (15 cm in diameter) containers in a pine bark: peat moss (3:1 v/v) substrate amended with 6 kg·m–3 MicroMax plus (Scotts Company, Inc., Marysville, Ohio). The plants were topdressed with 10 g SierraBlen 17–6–12 (Scotts Company, Inc., Marysville, Ohio) slow-release fertilizer. The liners received 0, 1, 2, 3, or 4 pinches and were pinched in a complete factorial 0, 2, 4, and 6 weeks after potting. There were 32 pinching treatments with 5 replications. The plants were grown outside until 30 Sept. 1996, when they were moved into a greenhouse. Plant height, width, and a visual rating were collected 13 Nov. 1996. There was no significant difference in plant size or visual rating of `Victor' regardless of the number or timing of pinches or of the number of liners per pot. `Zuni' had significantly the best visual ratings and largest size when grown with three liners but the timing and number of pinches had no significant effect. `Victor' is a dwarf cultivar growing to only 1 m in the landscape while `Zuni' is a semi-dwarf, growing to 2.7 m.

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BA and GA4+7, were applied to vegetative, mature Rudbeckia hirta plants at the beginning of long days (LD). There were no synergistic effects, but BA inconsistently affected branching and had no effect on flowering. Floral initiation of the terminal inflorescence was promoted by GA4+7, although axillary inflorescences were not. Increasing GA4+7 levels decreased the time to terminal inflorescence anthesis. However, the interval between the terminal and second axillary inflorescence anthesis was increased. The net result was no significant effect on the time to second axillary inflorescence anthesis. Gibberellins may enhance the LD effect on the apical meristem of Rudbeckia, but axillary meristems, which initiate later, remained unaffected. Chemical names used: benzyladenine (BA), gibberellin4+7, (GA4+7).

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