Common liverwort (Marchantia polymorpha) is a primitive, spore-bearing bryophyte that thrives in containerized ornamental crop propagation and production environments. It is one of the major weed problems in container nurseries and greenhouses because it competes with ornamental plants for soil/growing medium, nutrients, water, space, and oxygen within the container. As a result, its presence can reduce the overall quality and market value of the ornamental crop. Once established in nurseries and greenhouses, it spreads rapidly because of its ability to propagate both asexually and sexually. Currently, no effective methods of controlling common liverwort in container production systems are available because a significant knowledge gap exists. Therefore, research is needed to determine whether organic mulches (types, depths, moisture holding capacity, and particle size), biopesticides, and strategic placement of fertilizers within containers suppress or inhibit common liverwort growth and development. In addition, newer chemicals (both synthetic and organic) and combinations need to be tested on different growth stages of common liverwort. The objective of this review was to summarize previous and current research related to common liverwort control in container production, and to identify areas where additional research is needed either to improve current control methods or to develop new ones.
Manjot Kaur Sidhu, Roberto G. Lopez, Sushila Chaudhari, and Debalina Saha
Jennifer H. Dennis, Roberto G. Lopez, Bridget K. Behe, Charles R. Hall, Chengyan Yue, and Benjamin L. Campbell
Given recent consumer and market interest in more sustainable products and business practices, researchers conducted a nationwide survey of greenhouse and nursery crop growers to determine the current state of the industry in terms of sustainability. Growers were asked about the importance of sustainability, their views of state environmental regulations, sustainable practices in place and ones they would like to implement in the next 1 to 3 years, and interest in sustainable certification. None of the grower respondents in this survey were certified sustainable, but at least one fourth (25.8%) were interested in certification. More than half of the respondents currently recycle plastic pots, use controlled-release fertilizers, and composted plant waste. However, only 12% of growers want to use biodegradable plant containers or implement water conservation measures into their production system within the next 1 to 3 years. Grower respondents felt the biggest obstacle toward implementation was the sustainable production practice would not be compatible with their existing system of production.
Chengyan Yue, Jennifer H. Dennis, Bridget K. Behe, Charles R. Hall, Benjamin L. Campbell, and Roberto G. Lopez
Organically and locally grown food products have become increasingly popular in recent years. However, unlike food products, consumers purchase most outdoor plants for their aesthetic value rather than their nutritional value. Many of the health concerns related to food products might not be applicable to ornamental plants, so the demand for organic non-food plants is unknown. Using a survey with 834 participants from four states, we investigated consumer preference for ornamentals, vegetable transplants, and herbs grown: 1) organically, locally, and sustainably; 2) in energy-efficient greenhouses; and 3) in biodegradable, compostable, and recyclable containers. Our study found that consumers are not enthusiastic about plants or their fertilizers being “organic.” However, consumers are very interested in plants being produced locally, similar to the public's ever-increasing interest in local food products. Consumers are also interested in purchasing plants in containers that are more sustainable. Among the different types of containers, biodegradable and compostable pots are more desirable than recycled pots.
Arend-Jan Both, Bruce Bugbee, Chieri Kubota, Roberto G. Lopez, Cary Mitchell, Erik S. Runkle, and Claude Wallace
Electric lamps are widely used to supplement sunlight (supplemental lighting) and daylength extension (photoperiodic lighting) for the production of horticultural crops in greenhouses and controlled environments. Recent advances in light-emitting diode (LED) technology now provide the horticultural industry with multiple lighting options. However, growers are unable to compare technologies and LED options because of insufficient data on lamp performance metrics. Here, we propose a standardized product label that facilitates the comparison of lamps across manufacturers. This label includes the photosynthetically active radiation (PAR) efficacy, PAR conversion efficiency, photon flux density output in key wave bands, as well as the phytochrome photostationary state (PSS), red/far red ratio, and graphs of the normalized photon flux density across the 300–900 nm wave band and a horizontal distribution of the light output.
Charles R. Hall, Benjamin L. Campbell, Bridget K. Behe, Chengyan Yue, Roberto G. Lopez, and Jennifer H. Dennis
Currently, one of the most widely discussed topics in the green industry, which is promulgated by consumers exhibiting greater degrees of environmental awareness, is the issue of environmental sustainability. This has led to a desire for products that not only solve the needs of consumers, but are also produced and marketed using sustainable production and business practices. Consumers increasingly place a greater emphasis on product packaging and this has carried over to the grower sector in the form of biodegradable pots. Although various forms of these eco-friendly pots have been available for several years, their marketing appeal was limited as a result of their less-than-satisfying appearance. With the recent availability of more attractive biodegradable plant containers, a renewed interest in their suitability in the green industry and their consumer acceptance has emerged. The objective of this study was to determine the characteristics of biodegradable pots that consumers deem most desirable and to identify distinct consumer segments, thus allowing producers/businesses to more efficiently use their resources to offer specific product attributes to those who value them the most. We conducted a conjoint analysis through Internet surveys with 535 valid observations from Texas, Michigan, Minnesota, and Indiana. Our results show that on average, consumers like rice hull pots the most followed by straw pots. Our analysis identified seven market segments and corresponding consumer profiles: “Rice Hull Likers,” “Straw Likers,” “Price Conscious,” “Environmentally Conscious,” “Carbon Sensitive,” “Non-discriminating.” Idiosyncratic marketing strategies should be implemented by industry firms to market biodegradable containers to the identified consumer segments.
William B. Miller, Neil S. Mattson, Xiaorong Xie, Danghui Xu, Christopher J. Currey, Kasey L. Clemens, Roberto G. Lopez, Michael Olrich, and Erik S. Runkle
Ethephon [(2-chloroethyl) phosphonic acid] is a plant growth regulator that releases ethylene on application and can abort flowers, stimulate branching, and inhibit stem elongation. Although ethephon is used as a foliar spray during the commercial production of many ornamental crops, its effectiveness as a drench has not been widely investigated. We performed experiments to quantify the effects of an ethephon drench on growth and flowering of a range of bedding plant and Narcissus cultivars and to assess the effect of lime on ethylene release from a peat substrate. A substrate drench of 0, 100, 250, or 500 mg·L−1 ethephon was applied to 12 potted Narcissus cultivars at one location, and up to 200 mg·L−1 was applied to 24 cultivars of bedding plants at three locations. Compared with untreated controls, ethephon generally reduced plant height at flowering and the effect increased with increased concentration. For example, Narcissus treated with a 250 mg·L−1 ethephon drench had stems that were 20% to 40% shorter at the end of flowering than control plants. However, ethephon drenches generally caused a 2- to 3-day flowering delay, and two cultivars had a phytotoxic response. Among the bedding plants studied, a 100-mg·L−1 ethephon drench suppressed plant height at flowering by greater than 30% in Catharanthus, Celosia, Dianthus, and Verbena, but by only 10% to 15% in Lobelia, Lycopersicon, and Tagetes. The drenches also delayed flowering in 10 of the 16 crops measured and decreased dry mass accumulation in all of the crops measured. Ethephon release from peat substrate became maximal ≈120 h after application and was dramatically increased by incorporation of dolomitic lime up to a rate of 9.5 kg lime per m3 of peat. Collectively, these studies show that ethephon substrate drenches inhibit stem elongation in a broad range of floriculture crops, but can also delay flowering and reduce biomass accumulation.
Celina Gómez, Christopher J. Currey, Ryan W. Dickson, Hye-Ji Kim, Ricardo Hernández, Nadia C. Sabeh, Rosa E. Raudales, Robin G. Brumfield, Angela Laury-Shaw, Adam K. Wilke, Roberto G. Lopez, and Stephanie E. Burnett
The recent increased market demand for locally grown produce is generating interest in the application of techniques developed for controlled environment agriculture (CEA) to urban agriculture (UA). Controlled environments have great potential to revolutionize urban food systems, as they offer unique opportunities for year-round production, optimizing resource-use efficiency, and for helping to overcome significant challenges associated with the high costs of production in urban settings. For urban growers to benefit from CEA, results from studies evaluating the application of controlled environments for commercial food production should be considered. This review includes a discussion of current and potential applications of CEA for UA, references discussing appropriate methods for selecting and controlling the physical plant production environment, resource management strategies, considerations to improve economic viability, opportunities to address food safety concerns, and the potential social benefits from applying CEA techniques to UA. Author’s viewpoints about the future of CEA for urban food production are presented at the end of this review.