Search Results

You are looking at 1 - 10 of 13 items for :

  • Author or Editor: Paul. R. Fisher x
  • HortTechnology x
Clear All Modify Search

A methodology based on process-control approaches used in industrial production is introduced to control the height of poinsettia (Euphorbia pulcherrima L.). Graphical control charts of actual vs. target process data are intuitive and easy to use, rapidly identify trends, and provide a guideline to growers. Target reference values in the poinsettia height control chart accommodate the biological and industrial constraints of a stemelongation model and market specifications, respectively. A control algorithm (proportional-derivative control) provides a link between the control chart and a knowledge-based or expert computer system. A knowledge-based system can be used to encapsulate research information and production expertise and provide management recommendations to growers.

Full access

The objective of this study was to quantify water volume and nutrient content leached during propagation of herbaceous cuttings in commercial greenhouses. Nutrient concentrations in the fertigation solution, substrate, tissue, and leachate were measured between Jan. and Mar. 2006 at eight greenhouse locations in Michigan, Colorado, New Hampshire, and New Jersey. Grower management of the timing and concentration of nutrients applied to vegetatively grown calibrachoa (Calibrachoa ×hybrida) or petunia (Petunia ×hybrida) liner trays varied among the eight locations, ranging from 0.5 to 80 mg·L−1 nitrogen (N) in week 1 and from 64 to 158 mg·L−1 N in week 4. Over a 4-week crop period, applied nutrients averaged 4.9 g·m−2 N, 0.8 g·m−2 phosphorus (P), and 5.8 g·m−2 potassium (K), and leached nutrients averaged 1.1 g·m−2 N, 0.3 g·m−2 P, and 1.6 g·m−2 K. Leaching of nutrients and irrigation water was highly variable among locations. Leached water volumes ranged from 4.5 to 46.1 L·m−2 over 4 weeks and contained 0.29 to 1.81 g·m−2 N, 0.11 to 0.45 g·m−2 P, and 0.76 to 2.86 g·m−2 K. The broad range in current commercial fertigation practices, including timing of nutrient supply, concentration of applied fertilizer, and leaching volume, indicate considerable potential to improve efficiency of water and fertilization resources during propagation and reduce runoff.

Full access

Interest in hydroponic home gardening has increased in recent years. However, research is lacking on minimum inputs required to consistently produce fresh produce using small-scale hydroponic systems for noncommercial purposes. Our objectives were to 1) evaluate the effect of biweekly nutrient solution replacements (W) vs. biweekly fertilizer addition without a nutrient solution replacement (W/O) on final growth, yield, and nutrient uptake of hydroponic tomato (Solanum lycopersicum) plants grown in a greenhouse, and 2) characterize growth over time in a greenhouse or an indoor environment using W. For each environment, ‘Bush Goliath’ tomato plants were grown for 12 weeks in 6.5-gal hydroponic systems. The experiment was replicated twice over time. In the greenhouse, plants were exposed to the following day/night temperature, relative humidity (RH), and daily light integral (DLI) in 2018 (mean ± SD): 31 ± 6/22 ± 2 °C, 67% ± 8%, and 32.4 ± 7 mol·m‒2·d‒1; and in 2019: 28 ± 6/22 ± 3 °C, 68% ± 5%, and 27.7 ± 6 mol·m‒2·d‒1. For both experimental runs indoors, the day/night temperature, RH, and DLI were 21 ± 2 °C, 60% ± 4%, and 20 ± 2 mol·m‒2·d‒1 provided by broadband white light-emitting diode lamps. The W/O treatment resulted in a higher-than-desired electrical conductivity (EC) and total nutrient concentration by the end of the experiment. In addition, compared with the W treatment, W/O resulted in less leaf area, more shoot growth, less water uptake, and similar fruit number—but increased blossom-end-rot incidence, delayed fruit ripening, and lower fruit fresh weight. Nonetheless, the final concentration of all nutrients was almost completely depleted at week 12 under W, suggesting that the applied fertilizer concentration could be increased as fruiting occurs. Surprisingly, shoot biomass, leaf area, and leaf number followed a linear trend over time in both environments. Nonetheless, given the higher DLI and temperature, greenhouse-grown plants produced 4 to 5 kg more of fruit than those grown indoors, but fruit from plants grown indoors were unaffected by blossom-end-rot. Our findings indicate that recommendations for nutrient solution management strategies should consider specific crop needs, growing environments, and production goals by home gardeners.

Open Access

A wide range of water-treatment technologies is used to control waterborne microbial problems in greenhouse and nursery irrigation. An online modified Delphi survey was carried out to identify the perceived key attributes that growers should consider when selecting among water-treatment technologies and to characterize a list of 14 technologies based on those same attributes. The expert panel consisted of ornamental plant growers (n = 43), water-treatment industry suppliers (n = 28), and research and extension faculty (n = 34). The survey was delivered to the expert panel in two rounds. Response rate was 59% and 60% for the first and second rounds, respectively. Growers identified control of plant disease, algae, and biofilm as primary reasons for adopting technologies, whereas mandatory regulation was not a major reason for adoption. All 23 attributes (related to cost, system size, control of microorganisms, chemistry, ease of use, and regulation) were perceived to be important when selecting between water-treatment technologies. Injectable sanitizing chemicals such as chlorination were considered to have low capital cost, unlike technologies that required installation of more complex equipment, such as heat treatment, hydrogen peroxide, ozone, reverse osmosis, or ultraviolet radiation. Filtration (excluding membrane filtration) was the only technology not perceived to be effective to control microorganisms. Filtration and copper were not considered effective to control human food-safety pathogens. Ozone was rated the highest as a technology that removes or oxidizes agrochemicals. Chemical water treatments, as opposed to physical water treatments, were perceived to be sensitive to water quality parameters and to have residual effect through the irrigation. Chlorine gas was perceived to be the only technology for which regulatory permission would be an obstacle. All technologies were perceived to be effective in water with low electrical conductivity (EC) or in solutions containing water-soluble fertilizers. This survey documents perceived attributes of water-treatment technologies, which are most useful where experimental data are not yet available. Research and outreach needs were highlighted by cases where perceived attributes differed from available experimental data or where there was a lack of consensus between experts.

Full access

The objective of this study was to compare strategies using water-soluble fertilizers (WSF) and controlled-release fertilizers (CRF) to provide adequate nutrition during both production and consumer phases of petunia (Petunia ×hybrida). Strategies included a CRF with a second prill coating (DCT) that delayed initial nutrient release, compared with a conventional single-coated CRF (OSM) and WSF. Rooted cuttings of petunia were grown for 42 days in trade 1-gal (2.84-L) containers (the “production phase”) with WSF only, a low rate of combined WSF and substrate-incorporated OSM, or low and high label rates of WSF and top-dressed (TD) OSM (WSF + OSM TD), WSF and substrate-incorporated DCT (WSF + DCT), OSM, or a commercial blend of substrate-incorporated OSM and DCT (OSM + DCT). By the end of production phase after 42 days, all fertilizer strategies tested produced horticulturally acceptable plants in terms of chlorophyll index and number of flowers. In a subsequent “consumer phase,” plants were maintained in containers or were transplanted into a landscape and irrigated with clear water for 98 days. Plant performance [number of flowers, SPAD chlorophyll index, dry weight, and tissue nitrogen (N) level] was greater during the consumer phase in treatments with high rates of CRF compared with WSF only or lower rates of CRF. On the basis of nutrient release in a sand substrate without plants at 10, 21, or 32 °C, the DCT had delayed nutrient release compared with single-coated CRF. The release rates of all CRF products and the duration of the delay in release from DCT were temperature dependent. A partial budget found that the lowest cost treatment was WSF only at $0.02/container. Comparing at high application rates, using WSF + DCT ($0.085/container) was more expensive than incorporated OSM ($0.05/container) and had a similar cost to WSF + OSM TD ($0.084/container). The greatly improved consumer performance for plants with residual fertilizer compared with WSF provides an opportunity to add value and profitability if a slightly higher sales price could be obtained. Several fertilizer strategies are available depending on material and labor cost and availability and preferred crop management style.

Full access

Domestic production of ginger (Zingiber officinale) and turmeric (Curcuma longa) rhizomes is increasing. The objective of this study was to compare growth and rhizome yield of these crops using different container volumes and planting densities. Two greenhouse experiments that lasted 28 weeks each were conducted. In Expt. I, one sprouted rhizome of a single ginger variety (Bubba Blue) and four turmeric varieties (Hawaiian Red, BKK, White Mango, and Black) were transplanted into either small (1.5 gal) or large (13.3 gal) round containers. In Expt. II, either one or three sprouted rhizomes of two ginger varieties (Bubba Blue and Madonna) and two turmeric varieties (Indira Yellow and Hawaiian Red) were transplanted into either large (13.3 gal) or medium (3.9 gal) round containers. In Expt. I, there were an increase in plant growth and yield with increasing container volume, as both crops produced more than double the shoot, root, and rhizome fresh weight (FW) when grown in large compared with small containers. In Expt. II, rhizome yield of ginger was 44% higher in medium than large containers, and container volume did not affect yield in turmeric. Total dry weight (DW) was higher in plants grown in the larger container volume in both species in Expt. I, and turmeric only in Expt. II. However, ginger in Expt. II had an 18% higher plant DW in the medium compared with the large container. The higher density in Expt. II increased yield and biomass production per container compared with the lower density, regardless of variety and container volume. Overall, net revenue per container was higher in Expt. II than Expt. I because of the higher rhizome yield. In Expt. I, the higher yield of ginger compared with turmeric increased sales revenue of this species, despite a lower sales price per kilogram. In contrast, the higher yield of turmeric in Expt. II resulted in higher sales revenue and net revenue per container compared with ginger. Based on our results, medium containers could be used to minimize material and space costs for ginger and turmeric production under the conditions evaluated in our study.

Open Access

The objective was to evaluate and compare foliar spray and soil drench application methods of iron (Fe) for correcting Fe deficiency in hybrid calibrachoa (Calibrachoa × hybrida) grown in a container medium at pH 6.9 to 7.4. Untreated plants showed severe chlorosis and necrosis, stunting, and lack of flowering. An organosilicone surfactant applied at 1.25 mL·L-1 (0.160 fl oz/gal) increased uptake of Fe from foliar applications of both ferrous sulfate (FeSO4) and ferric ethylenediamine tetraacetic acid (Fe-EDTA). Foliar sprays at 60 mg·L-1 (ppm) Fe were more effective when Fe was applied as Fe-EDTA than FeSO4. Increasing Fe concentration of foliar sprays up to 240 mg·L-1 Fe from Fe-EDTA or 368 mg·L-1 Fe (the highest concentrations tested) from ferric diethylenetriamine pentaacetic acid (Fe-DTPA) increased chlorophyll content compared with lower spray concentrations, but leaf necrosis at the highest concentrations may have been caused by phytotoxicity. Drenches with ferric ethylenediaminedi(o-hydroxyphenylacetic) acid (Fe-EDDHA) at 20 to 80 mg·L-1 Fe were highly effective at correcting Fe-deficiency symptoms, and had superior effects on plant growth compared with drenches of Fe-DTPA at 80 mg·L-1 Fe or foliar sprays. Efficacy of Fe-DTPA drenches increased as concentration increased from 20 to 80 mg·L-1 Fe. An Fe-EDDHA drench at 20 to 80 mg·L-1 Fe was a cost-effective option for correcting severe Fe deficiency at high medium pH.

Full access

There are many water treatment technologies available to the nursery and greenhouse industry, but this sector has been somewhat hesitant to adopt them. An online survey was used to evaluate nursery and greenhouse growers’ knowledge, implementation, and continued use of 12 water treatment technologies. Less than 24% of the growers had used a water treatment technology. The knowledge level was low overall, and fewer than one in four growers had implemented all 12 technologies. However, most growers who had implemented 10 of the 12 technologies continued to use them. The results imply water treatment technologies available for this group are somewhat unknown and underused, thereby implying that there is a need to increase awareness of these innovations and highlight the opportunity for growers to advocate for treatment technology use among their peers.

Open Access

There are economic and knowledge-based challenges that must be addressed for indoor farms to be viable in the United States despite their potential benefits. A mixed-methods approach was used to identify the needs of specialty crop growers and stakeholders interested in or currently using indoor propagation environments to grow seedlings, cuttings, and tissue-cultured plants. An online survey evaluated specialty crop growers’ current use of indoor plant propagation environments and their needs related to indoor plant propagation. A focus group was then conducted to further understand the needs for indoor plant propagation by stakeholders. Industry participants were largely motivated to adopt indoor propagation environments to reduce crop losses (“shrinkage”), increase productivity per unit of land area, ensure faster germination or rooting, improve plant quality, and profit from anticipated economic benefits. Research and education priority areas identified by stakeholders included economic costs and benefits (including capital investment and energy costs), improved crop quality, production time, uniformity, reduced shrinkage, and strategies to improve light management indoors. Based on the results, research efforts must determine and prioritize the most important economic considerations and production advantages to fill important gaps in knowledge about indoor plant propagation.

Open Access

The objective was to analyze the physical, chemical, and biological water quality in horticulture irrigation systems in 24 ornamental plant greenhouses and nurseries in the United States. At each greenhouse or nursery, water was collected from up to five points (“Sample Types”) which included 1) “Source” from municipal or private well supplies, 2) “Tank” from enclosed storage containers, 3) “Subirrigation” from water applied to crops in ebb-and-flood systems, 4) “Furthest Outlet” that were irrigation emitters most distant from the Source, and 5) “Catchment Basin” from open outdoor retention areas. On average, Source water had the highest physical and microbial quality of Sample Types including the highest ultraviolet (UV) light transmission at 86%, lowest total suspended solids (TSS) at 3.1 mg·L−1, and lowest density of aerobic bacteria with 1108 cfu/mL of water. Average quality of recycled water from Subirrigation or Catchment Basins did not meet recommended levels for horticultural irrigation water for UV transmission (68% to 72% compared with recommended 75%), microbial counts (>100,000 cfu/mL compared with recommended <10,000 cfu/mL), and chemical oxygen demand (COD) (48.2 to 61.3 mg·L−1 compared with recommended <30 mg·L−1). Irrigation water stored in Tanks or applied at Furthest Outlets had lower physical and biological water quality compared with Source water. Level of aerobic bacteria counts highlighted a risk of clogged microirrigation emitters from microbial contaminants, with highest bacteria levels in recirculated irrigation water. The physical, chemical, and microbial water quality results indicate a need for more effective water treatment to improve biological water quality, particularly with recirculated irrigation.

Full access