Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Improved Production Methods: North South Initiative (North Carolina State University)

Location: Application Technology Research Unit

2009 Annual Report


1a.Objectives (from AD-416)
The objective of this research will focus on research to optimize nutrition and irrigation rates during different stages in floriculture crop development taking into account stock plant, propagation, and finishing environments.


1b.Approach (from AD-416)
Develop protocols to flower plants at a specified plant size for the retail environment, and extending the marketing season by producing early- or late-flowering plants for different locations in the U.S. A single product or tank mix growth retardant applications for new crops that reduce elongation most without delaying flowering and whether innovative practices such as rewetting of foliage increases efficiency of growth regulators. Identify the crops and stages of development in which lighting is most effective. In addition, photoperiodic lighting is increasingly being used to induce earlier flowering during the winter and spring. Determine how photoperiodic lighting can be maximized by investigating how light quantity, quality, and duration (including cyclic lighting) impact flowering of a range of popular garden plants. Potential energy savings will be quantified by optimizing light and temperature to produce crops in the most efficient and cost-effective manner for different locations in the U.S. Develop tools and techniques that allow growers to more precisely control and manipulate flowering of greenhouse crops. Techniques will be developed for producing 'programmed' liners that have the branching, height potential, and flower bud development necessary so that the liner can be simply transplanted and quickly finished. "Bud meters" will be developed for important floriculture crops so that growers can manage greenhouse environments in order to properly time flowering on finished crops or to possibly reduce greenhouse temperatures to save fuel costs while still hitting the targeted market dates. Determine optimal fertilziation rates and tissue nutrient levels to maximize growth of flowering plants and characterize the symptoms of nutritional disorders. Measure nutrient uptake through leaves, stems, and roots at different stages of rooting under greenhouse and controlled hydroponic conditions to match fertilizer supply with demand. Quantify the interaction of applied water and fertilizer rates on leaching of different forms of nutrients from propagation media. Identify the fertigation strategies that reduce nutrient leaching while maintaining crop health.


3.Progress Report

This congressionally mandated Specific Cooperative Project works in concert with four other projects for improvements in the efficient production of bedding plants. The primary focus of this part of the project is to investigate methods for improving the quality of rooted cuttings and young plants. This includes storage conditions, rooting environment, stock plant nutrition, and nutrition during plant establishment. The study currently in progress is comparing various simulated shipping lengths and propagation environments for propagation of vegetative annuals. Four propagation environments which include, contact-spun woven polyester cloth laid directly on cutting and misted periodically, humidity tent misted periodically, mist, and fog and three simulated shipping durations (0, 2, and 4 days) at 20°C will be compared on the rooting of several common bedding plant crops. Rooting, cutting quality, color, chlorophyll content, and cutting survival are being evaluated. For New Guinea impatiens, as storage time decreased quality increased. The humidity tent environment produced the highest quality of cuttings by visual inspection of cutting quality. No visual differences have been observed in rooting. For geranium, the quality rating was also higher for fewer days of storage. Many cuttings subjected to 4 days of storage died during the course of the study, while very few from 0 and 2 days of storage died. The exception was ‘Rocky Mountain Violet’, which was severely affected by storage, many of the 2 day storage cuttings died. Cutting quality will have to be fully analyzed to determine the best environment. In another aspect of this research, stock plant nutrition is being investigated. Appropriate stock plant nutrition and application of the correct quantity and form of nitrogen (N) in proportion to the rate of plant uptake need to be evaluated to determine their effects on the subsequent rooting of excised cuttings. A study has begun that will test various ratios of NO3- and NH4+ and N concentrations for their effects on rooting, carbohydrate status, and cutting survival with and without simulated shipping in zonal geranium and New Guinea impatiens. Similar nutrition studies investigating N ratios and concentrations will be conducted with the focus on plant establishment. Progress of this cooperative project was monitored through monthly electronic (email) communication, shared participation in industry-related educational courses, and twice annual face-to-face communication at national meetings.


Last Modified: 4/18/2014
Footer Content Back to Top of Page