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United States Department of Agriculture

Agricultural Research Service

Title: Actual Performance versus Theoretical Advantages of Polyacrylamide Hydrogel throughout Bedding Plant Production

Authors
item Frantz, Jonathan
item Pitchay, D - UNIVERSITY OF TOLEDO
item Locke, James
item Krause, Charles

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 14, 2005
Publication Date: November 1, 2005
Repository URL: http://hdl.handle.net/10113/16007
Citation: Frantz, J., Pitchay, D., Locke, J.C., Krause, C.R. 2005. Actual Performance versus Theoretical Advantages of Polyacrylamide Hydrogel throughout Bedding Plant Production. HortScience. 40:2040-2046.

Interpretive Summary: There are several commercial materials available that claim to be ideal for use in horticulture to assist in watering plants. These are often referred to as 'hydrogels.' It is widely known that the ability of these materials to hold water is altered in the presence of salts. Tap water can reduce the water holding capacity by 70% or more. Unfortunately, there is not much else that is widely known about these materials in terms of their performance and ability to help grow a plant. There has also been no calculations to provide a theoretical basis for the hydrogel performance in different environments. In a series of greenhouse and laboratory studies, we have evaluated the physical properties of a type of hydrogel and characterized the growth and development of pansy and New Guinea Impatiens. We measured leaf expansion, water content of the soilless media, root growth, flowering, and fresh and dry masses. We have found little to no differences in the rate of leaf expansion when using hydrogels, but enhanced root growth early after transplanting with the hydrogels. Our results indicated that plant growth was enhanced early in production, but any advantage they may have was lost by the end of production. Plants grown in hydrogels needed watering less frequently than those without hydrogel, but the effect was lost over time. Since the use of the material can add about 15% to the cost of potting media, this data is designed to assist growers in hydrogel use and to determine any benefits of the added costs.

Technical Abstract: There are several commercial materials available that have remarkable hydrating properties and many claim them to be ideal for use in horticulture for water delivery. These are often referred to as 'hydrogels.' There is general agreement in the literature that the physical characteristics of hydrogels are altered in the presence of divalent cations such as Ca2+ and Mg2+. Tap water can reduce the water holding capacity by 70% or more. Unfortunately, the literature agrees on little else in terms of the performance of hydrogels. There has been no mathematical performance evaluation of hydrogel and what affect the environment may play in that performance to predict potential irrigation savings or shelf life extension. In a series of greenhouse and laboratory studies, we have evaluated the physical characteristics of polyacrylamide hydrogel and characterized bedding plant performance throughout a typical growth cycle. We measured leaf expansion, water content of the media, root growth, flowering, and fresh and dry masses. We have found little to no differences in the rate of leaf expansion when using hydrogels, but enhanced root growth early in production with the hydrogels. Our results indicated that plant growth was enhanced early in production, but any advantage they may have was lost by the end of production. Plants grown in hydrogels needed irrigation less frequently than those without hydrogel, but the effect was diminished over time. Since the use of the material can add about 15% to the cost of potting media, this data is designed to assist growers in hydrogel use and to determine any benefits of the added costs.

Last Modified: 10/1/2014
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