Irrigation runoff water from a containerized landscape plant production bed was blended with rainwater from green house roofs in a constructed collection basin. Water from both the collection basin and an on-site potable well were characterized and used to grow foliage and bedding plants with overhead and ebb-and-flow irrigation systems. Over a 2-year period, a total of 18 foliage and 8 bedding plant cultivars were produced with plant growth and quality quantified. Alkalinity, electrical conductivity, hardness, and concentrations of nutrients of water from both sources were well within desired levels for greenhouse crop production. Turbidity and pH were relatively high from algal growth in the collection basin. However, substrate pH, irrigated by either water source, remained between 6 and 7 throughout the production periods. All plants at the time of finishing were of marketable sizes and salable quality independent of water source. No disease incidences or growth disorders related to water sources were observed. Results suggest that captured irrigation runoff blended with rainwater can be an alternative water source for green house crop production.
Jianjun Chen, Richard C. Beeson Jr., Thomas H. Yeager, Robert H. Stamps, and Liz A. Felter
Dharmalingam S. Pitchay*, Jonathan M. Frantz, and James C. Locke
Currently, formulation of inorganic fertilizers is based on cation amounts such as NH4, K, Mg, Ca, Fe, MN Cu, and Zn, whereas anion species and amounts are viewed, with few exceptions, as necessary fillers. The delivery of cations in the nutrient solution is associated with an anion such as Cl, SO4, NO3, PO4 or CO3. These anions at higher concentrations can result in different growth responses by altering the rhizosphere pH, soluble salts, and influencing the uptake of both cations and anions. The impact of these anions has not been extensively studied in the formulation of inorganic fertilizers. Several experiments assessed the effect of SO4 and Cl on root and shoot growth and development of bedding plants represented by petunia, impatiens, and vinca. In all treatments, plant height, shoot and root dry weight, and flower number decreased with an increase in Cl concentration. Root morphology was marked by fewer total roots and shorter primary and secondary roots when grown with Cl anions compared to the plants grown with SO4 anions. This indicates that anions have a larger role in determining optimum fertilizer formulation than previously believed. This information provides an additional tool in formulating fertilizers for greenhouse bedding plant production.
John A. Biernbaum, William Argo, and Janet Pumford
161 WORKSHOP 27 Use of Plant Sap Tests for Determining Nutrient Status of Horticultural Crops
Marc W. van Iersel
Bedding plants are exposed to a wide range of environmental conditions, both during production and in the landscape. This research compared the effect of short-term temperature changes on the CO2 exchange rates of four popular bedding plants species. Net photosynthesis (Pnet) and dark respiration (Rdark) of geranium (Pelargonium ×hortorum L.H. Bail.), marigold (Tagetes patula L.), pansy (Viola ×wittrockiana Gams.), and petunia (Petunia ×hybrida Hort. Vilm.-Andr.) were measured at temperatures ranging from 8 to 38 °C (for Pnet) and 6 to 36 °C (for Rdark). Net photosynthesis of all species was maximal at 14 to 15 °C, while Rdark of all four species increased exponentially with increasing temperature. Gross photosynthesis (Pgross) was estimated as the sum of Pnet and Rdark, and was greater for petunia than for the other three species. Gross photosynthesis was less sensitive to temperature than either Pnet or Rdark, suggesting that temperature effects on Pnet were caused mainly by increased respiration at higher temperatures. Gas exchange-temperature response curves were not useful in determining the heat tolerance of these species. There were significant differences among species in the estimated Rdark at 0 °C and the Q10 for Rdark. Differences in the Q10 for Rdark were related to growth rate and plant size. Large plants had a greater Q10 for Rdark, apparently because these plants had a higher ratio of maintenance to growth respiration than small plants. The Q10 of the maintenance respiration coefficient was estimated from the correlation between the Q10 and relative growth rate, and was found to be 2.5 to 2.6.
Clydette M. Alsup and Pamela A. Trewatha
The rocky Ozarks soils make it difficult for some homeowners to establish ornamental gardens. An alternative to digging in rocky soils is planting into bags of potting soil. This study evaluated “Gardening in a Bag” for herbaceous bedding plants. The growth and appearance of Alternanthera, Capisum annuum, Dianthus, Gazania, Tagetes `Wave', and upright petunias, Salvia splendens, Spilanthes, Verbena, and Catharanthus roseus were evaluated in 2002 under two planting methods: in the ground vs. in bags of potting soil. Wave petunias, Dianthus, C. roseus, and Portulacagrandiflora were evaluated in 2003. All plants were mulched with 3 inches of coarse sawdust. In 2002, planting method had no effect on average height for 16 of the 25 cultivars tested. Seven cultivars were taller when grown in the ground while two cultivars were shorter in that treatment. Planting method had no effect on average plant width of 13 of the cultivars. Plant width was greater for nine cultivars grown in bags, while three cultivars were wider when grown in the ground. Visual ratings were similar for 14 of the cultivars, regardless of planting method. In 2003, performance of five species was evaluated on 3 and 29 July and 5 Sept. Plant height and width were greater on plants grown in the ground than plants grown in bags on 3 July and 5 Sept. Only plant width was significantly greater in the soil-grown plants on 29 July, although the greater height trend was still evident. Plants in the ground had more flowers than plants in bags on 3 July, but there were no differences in flower number the other two dates. Visual quality ratings were taken on the second and third dates, with no differences between treatments. Root soil temperature was higher in bags than in the ground on all three dates in 2003.
This experiment was conducted to determine the effects of bed type (single or parallel raised bed vs. nonbedded); plant density (1991: ≈148,300 or 269,500 plants/ha; 1993: ≈148,300, 269,500, or 432,400 plants/ha); and use of black or white degradable mulch vs. nontreated soil on total and marketable yields and number of marketable seed per kilogram (seed count) of `Fleetwood', an erect bush, white-seeded navy bean (Phaseolus vulgaris L.). Spray-on mulch degraded before canopy closure, but a residue was present at harvest. In 1991, treatments did not affect yield or seed count. In 1993, bedding did not affect yield over nonbedded seedbeds. Black spray-on mulch increased marketable yield over plants grown with white spray-on mulch. Total and marketable yields were significantly higher at 269,500 than at 148,300 plants/ha. Bed type and plant density did not affect seed count, but seed count increased with black spray-on mulch. Dry beans should not be grown on beds under soil conditions such as those in our experiment. White spray-on mulch had no beneficial effect, but using black mulch needs additional evaluation. Planting at 269,500 plants/ha likely will yield ≈2 Mg seeds/ha in most years.
Jeff S. Kuehny, Blanca Morales, and Patricia Branch
Irrigation water quality is an important factor in ornamental plant production; however, there is little information in this area. Saline (NaCl) and alkaline (NaHCO3) water have been shown to cause general chlorosis, tip burn, and defoliation of plants. The growing medium used in crop production may be an important factor when irrigating with saline and alkaline water. Our objectives were to determine the effects of increasing concentrations of NaCl: CaCl2 and NaHCO3 in irrigation water on growth and development of spring and fall bedding plants grown in peat, peat/pine bark, and pine bark media. Plant dry weight, height, and width were significantly lower at 300 and 400 ppm NaCl: CaCl2 and NaHCO3 levels. Early visible symptoms were necrosis of leaf tips, some leaf discoloration and finally plant death in the NaCl: CaCl2 experiment. The leaves of plants in the NaHCO3 experiment became water soaked and chlorotic, and some leaf abscission occurred. The best plant growth in the NaHCO3 experiment occurred in peat and the best plant growth in the NaCl: CaCl2 experiment occurred in pine bark. Decreased uptake of K+, Ca++, and Mg++ occurred when high levels of sodium were present.
Richard O. Kelly, Zhanao Deng, Brent K. Harbaugh, and Rick K. Schoellhorn
Florida is one of the top wholesale producers of bedding plants, and in 2003 was ranked fourth in annual bedding plant production and fifth in potted pansy/viola production. Evaluation of pansy cultivars is vital for continued growth of the industry. We evaluated 210 cultivars of pansy (Viola ×wittrockiana) (164 new cultivars) in replicated class tests at the University of Florida's Gulf Coast Research and Education Center at Bradenton, Fla., from 2000–04 to determine the best-of-class and use them in future trials to compare against new entries in the same class. In this report, we provide objective plant measurements of vegetative and floral characteristics as well as subjective performance ratings. Subjective ratings were on a 1 to 7 scale with the highest rating of 7 for excellent. In general, overall performance ratings (combined foliage, flower, arthropod, and disease ratings) ≥5.5 were considered outstanding. Pansy cultivars were grouped into classes based on flower color and pattern. Best-of-class selections that had an outstanding overall performance rating in one or more contested trials, never falling below 5.0 in other contested trials, were: (black class) `Accord/Banner Black Beauty', (blue shades/tints class) `Nature Blue', (blue with blotch class) `Nature Ocean', (mix class) `Panola Clear Mixture', (pink shades/tints with blotch class) `Nature Pink Shades', [purple (dark), blue-violet with white cap class] `Nature Beacon', [purple (dark), blue-violet/white face with blotch class] `Panola Purple With Face', (purple with light eye class) `Baby Bingo Lavender Blue', (white class) `Nature White', (yellow class) `Nature Yellow', (yellow with blotch and purple, blue-violet cap class) `Iona Purple & Yellow With Blotch', (yellow with blotch and red cap class) `Bingo Red & Yellow', (yellow with blotch and red cap class) `Panola Yellow With Blotch', (yellow with dark veins class) `Whiskers Yellow'. We believe these cultivars would perform well in the southern U.S. or areas of the world with similar heat and cold hardiness zones.
Johnny Carter and Edwin K. Mathews
Paclobutrazol and three commercial growth retardants (B-nine, Cycocel and A-rest) were compared for their effectiveness in controlling the growth of five bedding plant species ('Yellow Boy' marigold, `Blue Blazer' ageratum, `Dreamland Orange' zinnia, `Better Boy' tomato and `Black Beauty' eggplant). Results showed that growth suppression depended on the treatment and species tested. All of the growth retardants suppressed the growth of `Yellow Boy' marigold. Growth of `Blue Blazer' ageratum was suppressed by all the treatments except for Cycocel. With `Dreamland Orange' zinnia, B-nine and Cycocel suppressed growth while Paclobutrazol and A-rest did not have any effect. All of the treatments except A-rest suppressed the growth of `Better Boy' tomato and `Black Beauty' eggplant.
Clydette M. Alsup and Pamela B. Trewatha
Many homeowners have difficulty establishing ornamental gardens in shallow, rocky soils. “Gardening in a Bag” (planting directly into bags of topsoil) offers a viable alternative for growing many herbaceous ornamental plants. This study compares the growth and appearance of several herbaceous bedding plants using “Gardening in a Bag” versus “in the ground” planting methods. Twenty-five cultivars of Alternanthera dentata R. Br., ornamental pepper (Capsicum annuum var. annuum L.), dianthus (Dianthus barbatus L.), gazania [Gazania rigens (L.) Gaertn.], marigold (Tagetes patula L.), petunia (Petunia hybrida hort. ex E. Vilm.), salvia (Salvia splendens Sellow ex Schult.), peek-a-boo plant (Spilanthes oleracea L.), verbena (Verbena hybrida hort. ex Groenl. & Rümpler), and vinca [Catharanthus roseus (L.) G. Don] were evaluated in 2002 under the two planting methods: in the ground versus in bags of topsoil. Wave petunias, dianthus, vinca, and rose moss (Portulaca grandiflora Hook.) were evaluated using the same methods in 2003. All plants were mulched with 7.5 cm coarse sawdust. In 2002, the planting method had no effect on the average height for 16 of the 25 cultivars tested. Seven cultivars were taller when grown in the ground whereas two cultivars were shorter during that treatment. Planting method had no effect on average plant spread of 13 of the cultivars. Plant spread was greater for nine cultivars grown in bags, whereas three cultivars were wider when grown in the ground. Visual ratings of overall appearance were similar for 14 of the cultivars regardless of planting method. In 2003, performance of the five species was evaluated on 3 July, 29 July, and 5 Sept. Planting method did not affect growth and appearance of rose moss or vinca. The two petunia cultivars and the dianthus tended to be taller and wider and had more flowers when grown in the ground compared with growth in bags. Visual quality of the petunias and the dianthus was unaffected by planting method until September when the `Purple Wave' petunias and the dianthus grown in the ground received better ratings than plants grown in bags.