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  • Author or Editor: John M. Dole x
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Three cut-flower species, Ageratum houstonianum `Tall Blue Horizon', Antirrhinum majus `Spring Giants Mix', and Helianthus annuus `Sunrich Orange' were grown in 806, 1801, or 1001 bedding plants flats resulting in 32 (85), 86 (280), and 156 (620) cm2 (mililiter medium)/plant, respectively. Plants were sown Sept. 1997 (fall), Dec. 1997 (winter), or Mar. 1998 (spring). Increasing area per plant decreased number of stems harvested but increased percent of stems harvested for all species. Increasing area per plant increased stem length and selling price for Antirrhinum and Helianthus; no significant difference was noted for Ageratum. Days to anthesis decreased with later planting for Antirrhinum and Helianthus; however, for Ageratum winter planting had the longest crop time and spring planting the shortest. Gross profit per square meter and square meter per week increased with decreasing area per plant for Ageratum and Helianthus; no significant difference was noted for Ageratum. Gross profit per square meter per week increased with later planting for all species. With all species 806 flats or spring planting required frequent irrigation, which would best be supplied by an automated irrigation system. Experiment was repeated in 1998/1999 using Carthamus tinctorius `Lasting Yellow', Celosia argentea `Chief Mix', Cosmos bipinnatus `Early Wonder', Helianthus annuus `Sunbright, Tagetes erecta `Promise Orange' and `Promise Yellow', and Zinnia elegans `Giant Deep Red' and `Oklahoma Mix'.

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`Blenda', `Leen v.d. Mark', `Monte Carlo', `Negritta' and `Paul Richter' tulip (Tulipa gesneriana) bulbs received a total of 15 weeks of cold (5°C) with 0, 2, 4, 6, 8, 10, or 12 weeks applied to dry, unpotted bulbs. The bulbs were then planted, watered, and exposed to cold for the remainder of the 15 weeks. Bulbs receiving up to 10 weeks dry, unpotted cold showed no decrease in flowering percentage and plant quality when compared to bulbs receiving 15 weeks of moist, potted cold. For bulbs receiving 12 weeks of dry cold, flowering percentage was generally lower when compared with 0-10 weeks of dry cold and varied with the cultivar and the year, i.e. 63% of `Paul Richter' and 100% of `Negritta' bulbs receiving 12 weeks of dry cold flowered in year one: whereas, 95% of `Paul Richter' and 70% of `Negritta' bulbs flowered in year two. For all cultivars, bulbs receiving 12 weeks of dry cold had the shortest shoots at the end of the cooling treatment compared with the other treatments. While final height varied significantly with the cultivar in year two, differences were not commercially noticeable. Final height was not influenced in year one.

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`Nellie White' Easter lily bulbs (Lilium longiflorum Thunb.) were given 6 weeks of 5.5C, placed in the greenhouse, and divided into groups based on number of days to emergence: 0 to 6, 7 to 13, 14 to 20, or 21 to 27 days. At emergence, the shoots received 0, 1, 2, or 3 weeks of long days (LDs). The experiment was repeated for 3 consecutive years. Late-emerging plants had fewer days from emergence to visible bud and anthesis than early-emerging plants. Consequently, late-emerging plants flowered within 3 to 11 days of early emerging plants despite 16 to 22 days difference in emergence time. Late-emerging plants were tallest, while plants emerging in the second week had the most leaves. Flower count was not influenced by emergence date in Year 1. In Year 2, flower count decreased curvilinearly with later emergence. In Year 3, flower count was highest in plants emerging in the second week and lowest in the last week. Increasing LDs decreased the number of days from emergence to visible bud and anthesis but increased plant height. LDs did not affect leaf count in any year or flower count in Years 1 and 2. In Year 3, flower count increased with increasing weeks of LDs. LD × emergence date interactions existed, but varied from year to year.

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Previous studies have shown that plants grown exclusively with controlled-release fertilizers (CRF) at recommended rates dramatically reduced N and P runoff but did not provide sufficient nutrients for optimum plant growth. `Gutbier V-14 Glory' poinsettias were grown in 15-cm pots ammended with CRF and drenched with 300 mg liter-3 NH4NO3 at: 1 week; 2 weeks; 1 and 3 weeks; 1, 3, and 7 weeks; 1, 3, 7, and 11 weeks after potting. Half the plants were grown with saucers underneath the pot to allow plants to reabsorb all leachate (no-leach). Control plants remained undrenched. For plants without saucers, all drenching treatments increased bract dry weights when compared to undrenched plants. Leaf dry weight increased with all drenching treatments except for 2nd week only treatment. Plants grown without saucers had greater leaf, stem and root dry weights, but similar bract and flower dry weights when compared to plants grown with saucers. Regardless of the use of saucers, nitrogen concentration in the leaf tissue tended to increase with greater number of NH4NO3 drenches and visual ratings were similar.

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Campanula medium L. `Champion Blue' and `Champion Pink' and Lupinus hartwegii Lindl. `Bright Gems' were grown in 8- or 16-h initial photoperiods, transplanted when 2-3, 5-6, or 8-9 true leaves developed, and placed under 8-, 12-, or 16-h final photoperiods. The lowest flowering percentage for `Champion Blue' (<1%) and `Champion Pink' (16%) resulted from plants grown in the 8-h photoperiod continuously. One hundred percent flowering occurred when Campanula were grown in the 16-h final photoperiod, indicating that `Champion Blue' and `Champion Pink' are long-day plants. Plants grown initially in the 8-h and finished in the 16-h photoperiod had the longest stems. Stem diameter was generally thickest for plants grown in the 8-h compared with the 16-h initial photoperiod. However, the 8-h initial photoperiod delayed anthesis compared with the 16-h initial photoperiod. `Champion Blue' and `Champion Pink' plants transplanted at the 2-3 leaf stage from the 16 hour initial to the 8-h final photoperiod had flowering percentages of 64% and 63%, respectively; however, when transplanted at the 8-9 leaf stage, plants were fully mature and 100% flowering occurred indicating that all plants were capable of flowering. In year 2, plants receiving high intensity discharge (HID) supplemental lighting during the 16-h initial photoperiod reached anthesis in 11 fewer days compared with plants not receiving HID supplemental lighting. High profits were obtained from Campanula grown in the 8-h initial photoperiod and transferred at 5-6 true leaves into the 16-h final photoperiod. Lupinus hartwegii plants had a high flowering percentage (96% to 100%) regardless of photoperiod or transplant stage. The 16-h final photoperiod decreased days to anthesis compared with the 8- or 12-h final photoperiod indicating that L. hartwegii is a facultative long-day plant. Increasing length of final photoperiod from 8- to 16-h increased stem length. Juvenility was not evident for Lupinus in this study. In year 2, Lupinus cut stems were generally longer and thicker when given HID supplemental lighting, especially when grown in the 8- or 12-h final photoperiod. Supplemental lighting also reduced days to anthesis. Highest profits were generally produced from Lupinus plants grown with supplemental HID lighting (during the initial photoperiod) until 8-9 true leaves had developed.

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These studies were conducted to determine the effect of 1) temperature on P leaching from a soilless medium amended with various P fertilizers, 2) water application volume on P leaching, and 3) various fertilizers on P leaching during production and growth of marigolds (Tagetes erecta L. `Hero Flame'). Increasing temperature linearly decreased leaching fraction; however, total P leached from the single (SSP) or triple (TSP) superphosphate-amended medium did not differ regardless of temperature. Despite a smaller leaching fraction at higher temperatures and no change in the total P leached, P was probably leached more readily at higher temperatures. More P was leached from the medium amended with uncoated monoammonium phosphate (UCP) than from the medium containing polymer-coated monoammonium phosphate (CTP) at all temperatures, and more P was leached from UCP-amended medium at lower temperatures than at higher temperatures. More P was leached from TSP- than from SSP-amended medium and from UCP- than from CTP-amended medium regardless of the water volume applied, but leachate P content increased linearly as water application volume increased for all fertilizers tested. Plant dry weights did not differ regardless of P source. Leachate electrical conductivity (EC) was lower with TSP than with SSP. Leachate EC was also lower with CTP than with UCP. A higher percentage of P from controlled release fertilizer was taken up by plants rather than being leached from the medium compared to P from uncoated fertilizers.

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Hyacinthoides hispanica (Mill.) Roth., Hyacinthus orientalis L. `Gypsy Queen', Narcissus pseudonarcissus L. `Music Hall', N. pseudonarcissus `Tahiti', Tulipa gesneriana L. `Couleur Cardinal', and T. gesneriana `White Emperor' bulbs were given 0 or 6 weeks of preplant 5 °C cold treatment and planted 15, 30, or 45 cm deep into raised ground beds under 0%, 30%, or 60% shade. Plant growth was monitored for 2 years after planting. Preplant 5 °C cold pretreatment reduced percentage of Tulipa `White Emperor' bulbs that flowered but did not affect the percentage of bulbs that flowered for the other species. Cold pretreatment also delayed anthesis in one or both years for all cultivars except Hyacinthoides hispanica. The greatest percentage of bulbs flowered when planted 15 cm deep. The 45-cm planting depth reduced bulb flowering percentage or eliminated plant emergence. Increasing planting depth increased days to anthesis for all cultivars in both years. Increasing shade increased stem lengths in year 2 for all cultivars except Hyacinthoides hispanica, but did not influence percentage of bulbs flowering for any cultivars. For all cultivars perennialization was low regardless of treatment as less than 30% of bulbs survived to the 2nd year.

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