Anemone (Anemone coronaria L.), snapdragon (Antirrhinum majus L.), larkspur [Consolida ambigua (L.) P.W. Ball & Heyw.], delphinium (Delphinium ×cultorum Voss.), sunflower (Helianthus annuus L.), lupine (Lupinus hartwegii Lindl.), stock [Matthiola incana (L.) R. Br.], and pansy (Viola ×wittrockiana Gams.) were grown in raised sandy loam ground beds in double-layered polyethylene-covered greenhouses which were either unheated (ambient) or had a 55 °F (13 °C) minimum night temperature in year 1 and 36 or 50 °F (2 or 10 °C) minimum night temperature in year 2. Results were species specific; however, the extreme low temperatures [21 °F (-6 °C)] in the unheated house limited delphinium and lupine production. The warmest greenhouses (55 and 50 °F) reduced production time for anemone, delphinium, larkspur, lupine (year 2), snapdragon (year 2),stock, and sunflower. The coolest greenhouses (unheated and 36 °F) increased stem lengths for anemone (year 2), delphinium, larkspur (year 1), lupine (year 2), snapdragon, stock, and sunflower. The coolest green-houses also yielded a profit or lower net loss for all species except delphinium, lupine, and snapdragon (year 2) for which profits were highest or net losses were lowest in the warmest greenhouses.
Todd J. Cavins, John M. Dole, and Vicki Stamback
Nicole L. Shaw and Daniel J. Cantliffe
Mini or “baby” vegetables have become increasingly popular items for restaurant chefs and retail sales. Squash (Cucurbita pepo) are generally open-field cultivated where climate, insect, and disease pressures create challenging conditions for growers and shippers who produce and market this delicate, immature fruit. In order to overcome these challenges, in Spring 2003 and 2004, 18 squash cultivars, including zucchini, yellow-summer, patty pan/scallop, and cousa types, were grown hydroponically in a passively ventilated greenhouse and compared for yield of “baby”-size fruit. Squash were graded as “baby” when they were less than 4 inches in length for zucchini, yellow-summer, and cousa types and less than 1.5 inches diameter for round and patty pan/scallop types. In both seasons, `Sunburst' (patty pan) produced the greatest number of baby-size fruit per plant, while `Bareket' (green zucchini) produced the least. The zucchini-types produced between 16 and 25 baby-size fruit per plant in 2003. The yellow summer squash-types produced on average 45 baby fruit per plant. The production of the patty pan/scallop types ranged from 50 to 67 baby-size fruit per plant depending on cultivar. The cousa types produced approximately 30 baby-size fruit. Total yields were lower in 2004 due to a shortened season. Squash plants will produce numerous high quality baby-sized fruit when grown hydroponically in a reduced pesticide environment of a greenhouse where they can be harvested, packaged, and distributed to buyers daily. The cultivars Hurricane, Raven, Gold Rush, Goldy, Sunray, Seneca Supreme, Supersett, Butter Scallop, Sunburst, Patty Green Tint, Starship, Magda, and HA-187 could be used for hydroponic baby squash production.
K.M. Kelley and J.A. Biernbaum
Eight species of edible flowers were grown in 12.5-cm (1.5-L) square containers during the months of November through May, in a root medium suitable for organic certification or a standard peat and perlite mixture with preplant fertilizer. Plants were fertilized with 200 mL of either a water-soluble fertilizer (19–1.8–19) at 300 ppm N, fish emulsion (5–0.4–0.8), or a certified organic, commercially available soluble fertilizer (6–2.6–5), each at 300 or 600 ppm N applied every 2 weeks. Shoot fresh and dry weights were measured and percent dry weight was calculated. The fresh weights for all species were highest for plants fertilized with the organic fertilizers. For all but one species the organic fertilizer treatments had the same or higher dry weights than the inorganic control. The percent dry weights for all species were the same or higher for the inorganic control treatment. The effect of the organic fertilizer rate on the dry weight was species-dependent. The highest flower production generally occurred with 300 ppm N. Flower size was measured for Viola tricolor and Viola ×. wittrockiana species. For both species flower size was smallest for plants fertilized with the 600 ppm certified organic fertilizer. Root media pH and EC were tested at 6-week intervals throughout the experiment. In general, the pH increased from the first to the second sampling date, but only increased or decreased slightly for later dates, and there was little effect of fertilizer type. Root media EC decreased initially with minimal change later.
Caroline S. Donnelly and Paul R. Fisher
The objective was to quantify the effect of supplemental lighting on cutting production for 10 herbaceous annual cultivars. Stock plants of four cultivars (Heliotropium arborescens `Atlantis', Petunia `Supertunia Sun Snow', Scaevola aemula `New Wonder', and Verbena `Tapien Soft Pink') received ambient light [average 6.2 mol·m-2·d-1 photosynthetic photon flux (PPF) during the photoperiod], or ambient light plus either 1.6 or 2.8 mol·m-2·d-1 PPF from high-pressure sodium (HPS) lamps for 11 hours. In a second experiment, the same four species plus six other cultivars were grown under ambient light (average 7.9 mol·m-2·d-1 PPF) or ambient plus 1.9 mol·m-2·d-1 PPF from HPS. The effect of HPS on the production of cuttings varied greatly between species. Growth of Heliotropium was not significantly affected by light level in either experiment. In the first experiment, the addition of 1.6 mol·m-2·d-1 PPF from HPS increased the number of Petunia `Supertunia Sun Snow', Scaevola, and Verbena cuttings by 14%, 51%, and 12%. The addition of 2.8 mol·m-2·d-1 PPF from HPS, increased cuttings harvested from these three species by 23%, 73%, and 22% respectively. In the second experiment, Petunia `Supertunia Sun Snow', Scaevola, Aloysia triphylla (lemon verbena), and Osteospermum `Lemon Symphony' had a positive cutting production response to HPS (17% to 45% increase), whereas cutting numbers of other species (Argyranthemum `Summer Melody', Lantana `Patriot Firewagon', Impatiens New Guinea hybrid `Pedro', Petunia `Supertunia Blue Wren', and Verbena) were not significantly affected by HPS. In both experiments, cutting quality (length, stem caliper, fresh mass, and dry mass) and subsequent rooting of cuttings were not significantly affected by light level.
William Garrett Owen
fertilized with 100–300 mg·L −1 N were 2.5–3.3 and 3.3–3.8 mg·L −1 Cu at 2–4 WAT ( Table 3 ), respectively, and were lower than those previously published for the genera Hibiscus . However, Cu deficiency is uncommon in greenhouse production ( Jeong et al
W. Garrett Owen
.0 to 7.9, 6.4 to 7.1, and 5.5 to 5.8 mg·kg −1 Cu, respectively ( Table 3 ). Though the lowest Cu tissue concentration was observed in ‘Peppermint Spice’, no deficiency symptoms were observed because Cu deficiency is uncommon in greenhouse production
Richard H. Merritt and K.C. Ting
A phase change material (PCM) energy storage unit operating in a greenhouse from 29 Oct. through 21 Dec. 1992 cooled it on the average 1.7C in the day and warmed it 2.2C at night due to both sensible and latent heat absorbed, released, and circulated. Tagetes patula `Mighty Marietta' and `Early Queen Sophia' marigolds and Viola × Wittrockiana `Yellow Blotch' and `Blue Blotch' pansies were grown in a PCM and a control (no PCM) greenhouse. Temperatures went below 0C 10 days in the control greenhouse and 4 days in the PCM greenhouse. The lowest temperature of -7.8C killed the marigolds in the control greenhouse. Neither marigolds nor pansies were killed in the PCM greenhouse, which attained a low temperature of -3.3C. On 4 Dec., plants were destructively harvested. Morphologically the marigolds were taller, and had more leaf area and dry matter when grown in the PCM greenhouse as compared to the control, but pansies were taller, and had more leaf area and dry matter when grown in the control greenhouse, as compared to the PCM greenhouse.
Milton E. Tignor, Sandra B. Wilson, Gene A. Giacomelli, Chieri Kubota, Efren Fitz-Rodriguez, Tracy A. Irani, Emily B. Rhoades, and Margaret J. McMahon
,000 acres of horticultural crops produced under protected environments in the United States ( U.S. Dept. of Agriculture, 2002 ). More than 84 greenhouse-related courses are offered by instructors at land-grant institutions to teach greenhouse production and
Patrick H. Kingston, Carolyn F. Scagel, David R. Bryla, and Bernadine Strik
The purpose of the present study was to investigate the suitability of different soilless substrates for container production of highbush blueberry (Vaccinium sp.). Young plants of ‘Snowchaser’ blueberry were grown in 4.4-L pots filled with media containing 10% perlite and varying proportions of sphagnum moss, coconut (Cocos nucifera L.) coir, and douglas fir [Pseudotsuga menziesii Mirb. (Franco)] bark, as well as a commercially available mix of peatmoss, perlite, and other ingredients for comparison. Total plant dry weight (DW) was similar among the treatments at 72 days after transplanting, but at 128 days, total DW was nearly twice as much in the commercial mix and in media with ≥60% peat or coir than in media with ≥60% bark. Inadequate irrigation likely played a role in poor plant growth in bark. Bark had lower porosity and water holding capacity than peat, coir, or the commercial mix and, therefore, dried quickly between irrigations. Bark also reduced plant uptake efficiency of a number of nutrients, including N, P, K, S, Ca, Mg, Mn, B, Cu, and Zn. Uptake efficiency of P, K, and Mg also differed between plants grown in peat and coir, which in most cases was a function of the initial concentration of nutrients in the media. Before planting, peat had the highest concentration of Mg and Fe among the media, whereas coir had the highest concentration of P and K. Leachate pH was initially lowest with peat and highest with coir but was similar among each of the media treatments by the end of the study. Electrical conductivity (EC) of leachate never exceeded 0.84 dS·m−1 in any treatment. Overall, peat and coir appear to be good substrates for container production of highbush blueberry. Bark, on the other hand, was less suitable, particularly when it exceeded 30% of the total media composition.
Erfan K. Vafaie, H. Brent Pemberton, Mengmeng Gu, David Kerns, Micky D. Eubanks, and Kevin M. Heinz
In this study, we surveyed the initial whitefly (Aleyrodidae) populations on rooted poinsettia (Euphorbia pulcherrima) cuttings at two commercial greenhouse facilities in both 2017 and 2018 to determine the initial whitefly population at the beginning of poinsettia production and surveyed finished poinsettias at multiple retailers in Tyler, TX, over 2 years to determine whitefly densities considered acceptable by retailers. The initial whitefly population (mean ± se) for all poinsettias was 0.02 ± 0.02 (2017) and 0.33 ± 0.13 (2018) nymphs per plant for grower facility A and 0.05 ± 0.05 (2017) and 0.02 ± 0.01 (2018) nymphs per plant for grower facility B. Of the total 2417 rooted poinsettia cuttings inspected at both locations over 2 years, 29 cuttings had whitefly nymphs (1.2%), 18 had pupae (0.7%), and 23 had exuviae (1.0%). On finished poinsettias sampled at retailers, 4.38 to 40.38 immatures (nymphs + pupae) per plant were found within 60 seconds for any given retailer over the 2 years. We found poinsettias with as many as 220 immatures and 32 adults on a single plant at retailers. This study is the first to quantify densities of whiteflies at retail stores over multiple years.