BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 1

Environmental sustainability or being “green” has gained a foothold in a wide range of consumer products, from organic foods to energy-efficient lightbulbs to eco-friendly packaging. Such sustainable alternatives are widely available and generally bring a price premium. The green industry has many opportunities to advance the environmental sustainability of production, including adopting Integrated Pest Management, enhancing water use efficiency, reducing pesticide use and runoff, and improving energy efficiency. These steps are not often visible to consumers, and, therefore, are not as easy to market. However, one highly recognizable opportunity is alternative containers.

Most ornamental plants are produced and sold in conventional, petroleum-based plastic containers made from nonrenewable resources. These products can be recycled or reused, but recycling is not always available, and reusing containers increases the risk of disease outbreaks. Therefore, many used nursery containers end up in the landfill or in a nursery storage area. Alternative containers are not new, but never have there been so many options. With the recent development of more than 10 types of alternative containers, it is likely that there is an option suitable for almost every nursery or greenhouse operation.

W 337-A

BEYOND PLASTIC POTSPart 1: Compostable, Plantable and Other Containers for Nursery Crop Production

Quinn Cypher, Extension AssociateAmy Fulcher, Assistant Professor

Department of Plant Sciences

Part I of this four-part series, “Beyond Plastic Pots,” provides an overview of compostable, plantable and other alternative nursery containers. Part II examines the appropriate uses of compostable and other alternative containers, including those made from recycled plastic. Part III explores the advantages and constraints of plantable containers. Part IV compares the key features of available alternative containers in an at-a-glance table format and highlights their advantages and constraints. This publication summarizes relevant research including recent findings from the University of Tennessee Institute of Agriculture and partner universities.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 2

Switching from petroleum-based plastic containers to an eco-friendly alternative is a highly visible means to meet consumer demand for sustainable products while capitalizing on a consumer’s willingness to pay for eco-friendly products, including alternative containers. It is not only possible to produce an equivalent product using alternative containers — it may be advantageous in certain situations. Waste, nonrenewable resource use and the overall carbon footprint of ornamental crops can be reduced through the use of alternative containers. Environmental sustainability and carbon footprint concerns have driven the development of three categories of alternative containers: compostable, plantable and other alternative containers that we refer to in this series as R3 containers. R3 containers are composed of recycled plastic and/or bio-based plastic, can often be recycled, and are suitable for reuse. They can have rigid sidewalls like a traditional nursery container or be collapsible due to their geotextile fabric construction. Compostable and plantable containers are broadly referred to as “biocontainers” as they are made from biodegradable materials. These three categories are used here for clarity and are not absolute. For example, some R3 containers will degrade, while some compostable fiber containers could be planted if aged or if the sides are cut. Most of the available alternative containers have been researched thoroughly, and this resource along with referenced information will allow growers to make informed decisions regarding adopting compostable, R3 and plantable pots.

Compostable ContainersCompostable containers are made from materials that will decompose when the plant is removed and they are composted. Containers made from rice hulls, PLA (polylactic acid), recycled paper and/or cardboard are currently available commercially. Soy, corn, bamboo, poultry feathers, wheat starch and other natural fiber waste products have been used to make compostable containers and may become available commercially as the demand for biocontainers grows.

R3 Containers (Recycled Plastic and/or Bio-based Plastic Containers)Containers in this class are made from either recycled plastics or a blend of petroleum-based plastics, bioplastics and natural fibers. Typically, these containers can be reused and/or recycled. Containers in this class can be made to mimic the form and function of conventional plastic containers or provide an alternative such as a fabric container. Although fabric containers made from recycled plastic and natural fibers do not decompose, they will disintegrate over time due to the natural fiber component.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 3

Plantable ContainersPlantable containers are a class of containers in which the pot does not need to be removed before planting. The most common plantable containers are made from a combination of peat and wood pulp or paper fibers. Other materials used to produce commercially available containers include coconut coir fiber, wood pulp, paper, cow manure and rice hulls. When plantable containers are installed in the landscape, roots pass through the container walls and into the surrounding soil as the containers decompose.

Figure 1. Compostable container

Fig. 2 (photo credit: Robert Geneve)Fig. 3

Fig. 1 (photo credit: Diana Cochran)

Figure 2. Root Pouch (fabric made from recycled plastic bottles and natural fibers)

Figure 3. Plantable container

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 4

Plant GrowthAlternative containers have a variety of characteristics that can aid production. Container type can influence plant growth through the effects of porous sidewalls (i.e., higher water use, reduced root circling, and by supplying nitrogen to the plants as they decompose). Alternative containers can improve growth, and several studies have shown the potential to increase shoot biomass, root biomass and overall growth. Although a few studies have shown reduced growth in some alternative containers (see

Water Use section below), the majority have concluded that alternative containers provide acceptable plant growth and appearance. As long as the correct container type is chosen, a nursery should be able to easily produce a product that can compete with one grown in a conventional container. Plant size, health, vigor and appeal of the entire finished product (including the container) can be matched or exceeded using the appropriate alternative container.

Figure 4. Plant growth in plastic and alternative containers (photo credit: Diana Cochran)

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 5

Water use in above ground outdoor production using alternative containers is impacted by weather and varies with location. Higher container porosity generally results in higher water loss. For example, 1-gallon coir containers used 1.2-1.4 timesmore water in Kentucky, Mississippi andTexas compared to conventional black plasticcontainers but used equivalent irrigation inTennessee, likely due to higher rainfall thatseason. Generally, pots made out of bio-plastic and solid rice hulls (compostablecontainers) require about the same volumeand frequency of irrigation as plastic pots.While greater container porosity generally

Water UseIn some alternative containers, it may be necessary to increase the frequency and/or volume of irrigation to produce a crop that is equivalent to one grown in a conventional plastic container. Alternative containers have varying degrees of porosity, which impacts water loss through the sidewalls. Water loss must be taken into account when making the switch to plantable containers because watering regimes used with plastic containers can result in decreased plant growth. Plantable pots have the highest water loss rates through their sidewalls and can require 1.4 to 2.6 times more water for greenhouse crops compared to black plastic containers.

Figure 5. Water use of alternative containers (photo credit: Robert Geneve)

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 6

leads to higher water requirements, high temperatures also influence crop water requirements in outdoor nurseries. Nonporous containers made from keratin (currently not available commercially) used less water than conventional black plastic containers, likely due to their light color. Therefore, it is possible for biocontainers to outperform plastic containers in terms of water use. The irrigation application technique used may also affect water requirements. For example, using an ebb-and-flood system with 1-gallon bioplastic, solid rice hull, slotted rice hull, paper and coconut fiber containers all had similar water requirements. Many options are available to reduce water consumption including shuttle trays that cover the porous sidewalls of containers, pot-in-pot production, substrate amendments and optimized irrigation scheduling.

Water use research presented in this series is narrowly focused on comparing container type. Growers interested in conserving water have options when considering their overall operation. For information on water conservation and sustainable irrigation, see Extension publications W 278-W 280:

Sustainable Nursery Irrigation Management Series, Part I. Water Use in Nursery Production W 278

utextension.tennessee.edu/publications/Documents/W278.pdf

Sustainable Nursery Irrigation Management Series, Part II. Strategies to Increase Nursery Crop Irrigation Efficiency W 279

utextension.tennessee.edu/publications/Documents/W279.pdf

Sustainable Nursery Irrigation Management Series, Part III. Strategies to Manage Nursery Runoff W 280

utextension.tennessee.edu/publications/Documents/W280.pdf

Container Strength during Production and TransportTo be viable, alternative containers must be able to withstand the production process, loading and transportation, as well as endure an unpredictable amount of time in a retail setting. Alternative containers have varying strengths depending on material and manufacturing process and are suited for different crops. Compostable containers are generally stronger and perform well in production cycles of up to one year. Plantable containers are typically weaker than compostable and recyclable containers, with the notable exception of the slotted rice hull and coir containers (plantable containers with high strength). Plantable containers are likely best suited for annual bedding crops, vegetables, and single-season production cycle perennial and woody crops. Because plantable containers are designed to decompose in the landscape, depending on the material and the weather these containers may begin decomposing in the nursery. Certain containers in this group can also grow algae during nursery production.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 7

The Bottom Line — Economics of Alternative ContainersSwitching from plastic containers to alternative containers affects the cost of different stages of production, making the question of “How will this affect my profit margin?” somewhat challenging to answer. The two biggest factors influencing the profitability of alternative containers are the cost of the container and the ability to charge a premium price for the product. Typically, alternative containers are more expensive than plastic pots; however, the prices for both fluctuate. Also, many alternative containers are relatively new, and the price will likely fall as their availability increases.

Changing container types has the potential to affect both the production costs and sale price of the product, and each type of container will have a different effect. The factors influencing the cost of production include the price of the container, potential changes in water use, changes in production time, potential decrease in portability, potential changes in fertilizer use, and increase in sale price due to consumer willingness to pay more. Additionally, some alternative containers are somewhat larger or smaller than their conventional petroleum-based plastic counterparts, which may alter the amount of substrate, fertilizer, pesticides and water, as well as shipping costs (for receiving new containers and shipping out finished plants). Nurseries that typically reuse their containers would see an

increased cost after adopting nonreusable alternative containers; however, storing and sanitizing old containers and the labor and cost associated with those tasks would be eliminated. Most of the changes in costs are marginal, suggesting that if the additional cost of the container can be offset by an increased sales price, alternative containers become an economically viable alternative. Each of the three classes of containers (compostable, R3 and plantable) will have a different effect on production costs and sale price and are addressed specifically in Parts II and III of this series.

Several studies have attempted to quantify the value that consumers place on alternative containers and have concluded that they are often willing to pay a premium price for alternative containers. Generally, consumers are likely to pay the highest price premium for compostable containers, followed by recycled and/or plantable depending on their attitude toward the environment. In an experimental auction where real money and product exchanged hands, consumers were willing to pay 58 cents more for chrysanthemums in 4-inch rice hull pots, 37 cents for straw pots and 23 cents for wheat starch pots when compared to 4-inch plastic pots. As of 2015, the price of a 4-inch rice hull pot was 12 cents, and an equivalent plastic container was 7 cents; therefore, the price premium needed to recoup the additional cost was minimal — just 5 cents per container (prices will vary by quantity purchased and supplier). The price premium may not stand in all markets and will likely depend on the type of sale (commercial or retail) and the volume (flats or individual plants).

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For flats of groundcover plants, large commercial buyers were more likely than small companies to buy plantable over plastic containers. Most retail consumers didn’t prefer flats of groundcover plants in plantable containers over plastic; however, older consumers and consumers with children did. (Note: Retail customers surveyed for container preference of groundcovers were a subset of customers from a single garden center and not necessarily representative of retail customers at large.) In a related study, the time to install (not including job site cleanup and used container disposal) was 20 percent faster for groundcovers in plantable containers, underscoring the need for marketing the value-added aspects and promotion of the benefits of alternative containers to buyers. Although container prices and consumer preferences change over time, alternative containers appear to be viable in many markets.

A Word of CautionAs illustrated above, many consumers value products that are produced using eco-friendly practices and are willing to pay more for “green” products. However, making false claims or exaggerating the environmental benefit of an alternative container (i.e., greenwashing) can have negative consequences and result in profit losses. A clear knowledge of the environmental benefits of these products is essential for nursery producers to promote them accurately.

Compostable, R3 or Plantable — Which is Right for You?Alternative containers are a highly visible means to “green” the green industry and a wide variety of containers are available. Not only can a competitive product be produced, but alternative containers can be beneficial during production and marketing. Meeting consumers’ demands for green products will improve the environmental sustainability of the nursery industry, can be economically advantageous, and can be achieved with proper alternative container selection and use.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 9

Additional information on the characteristics of compostable, recycled and plantable containers is provided in Part II (W 337-B), Part III (W 337-C) and Part IV (W 337-D) of this series. Part IV is an at-a-glance table format comparison of several alternative containers.

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Beeks, S.A. and M.R. Evans. 2013. Growth of cyclamen in biocontainers on an ebb-and-flood subirrigation system. HortTechnology 23:173-176.

Beeks, S.A. and M.R. Evans. 2013. Physical properties of biocontainers used to grow long-term greenhouse crops in an ebb-and-flood irrigation system. HortScience 48:732-737.

Brumfield, G.R., A.J. DeVincentis, X. Wang, R.T. Fernandez, S. Nambuthiri, R.L. Geneve, A.K. Koeser, G. Bi, T. Li, Y. Sun, G. Niu, D. Cochran, A. Fulcher, and J.R. Stewart. 2015. Economics of utilizing alternative containers in ornamental crop production systems. HortTechnology 25:17-25.

Camberato, D. and R. Lopez. 2010. Biocontainers for long-term crops. Greenhouse Grower. 28:27-28.

Center for Applied Horticultural Research. 2009. Effect of biocontainer type on shoot and root growth of tomatoes and coir pot effect on field establishment on tomato plants. 31 Dec. 2013. cfahr.org/center/AnnualReport.html

Center for Applied Horticultural Research. 2010. Performance of biopots under greenhouse conditions. 17 April 2015. cfahr.org/2010AnnualReport/Part9.pdf

Conneway, R., S. Verlinden, A.K. Koeser, M. Evans, R. Schnelle, V. Anderson, and J.R. Stewart. 2015. Useof biocontainers for long- and short-term greenhousecrop production. HortTechnology 52:26-34.

Curry, C., J. Schrader, K. McCabe, W. Graves, D. Grewell, G. Srinivasan, and S. Madbouly.2014. Soy containers: Growing promise, growingplants. GrowerTalks February, p. 60-65.

Evans, M.R., A.K. Koeser, G. Bi, S. Nambuthiri, R. Geneve, S.T. Lovell, and J.R. Stewart. 2015. Impact of biocontainers with and without shuttle trays on water use in the production of a containerized ornamental greenhouse crop. HortTechnology 25:35-41.

Evans, M.R. and D.L. Hensley. 2004. Plant growth in plastic, peat, and processed poultry feather fiber growing containers. HortScience 39:1012-1014.

Evans, M.R. and D. Karcher. 2004. Properties of plastic, peat and processed poultry feather growing containers. HortScience 39:1008-1011.

Fulcher, A., D.R. Cochran, and A.K. Koeser. 2015. An introduction to the impact of utilizing alternative containers in ornamental crop production systems. HortTechnology 25:6-7.

Gilman E.F., C. Harchick, and M. Paz. 2010. Effect of container type on root form and growth of red maple J. Environ. Hort. 28(1):1-7.

Hall, C.R., B.L. Campbell, B.K. Behe, C. Yue, R.G. Lopez, and J.H. Dennis. 2010. The appeal of biodegradable packaging to floral consumers. HortScience 45:583-591.

Ingram, D. and S. Nambuthiri. 2012. Using plantable containers for selected groundcover plant production. ASHS Annual Meeting. HortScience 47(9):S22 (Abstr.).

Ingram, D.L., T.A. Woods, W. Hu, and S. Nambuthiri. 2015. Willingness-to-pay comparisons for flats of groundcover plants in plantable containers: Consumers versus commercial buyers in Kentucky. HortScience 50(3):408-411.

Jiffy Pots. 2015. Jiffy CarbonLite. 12 January 2015. http://www.jiffygroup.com/assets/files/ProductSheets/Jiffy%20CarbonLite/Jiffy%20CarbonLite_USA_Salesheet%201%20sided-06-10LR.pdf

Khachatryan, H., B. Campbell, C. Hall, B. Behe, C. Yue, and J. Dennis. 2014. The effects of individual environmental concerns on willingness to pay for sustainable plant attributes. HortScience 49:69-75.

Koeser, A.K., G. Kling, C. Miller, and D. Warnock. 2013. Compatibility of biocontainers in commercial greenhouse crop production. HortTechnology 23:149-156.

References and Resources

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Koeser, A.K., S.T. Lovell, M.R. Evans, and J.R. Stewart. 2013. Biocontainer water use in short-term greenhouse crop production. HortTechnology 23:215-219.

Koeser, A.K., S.T. Lovell, A.C. Petri, R.G. Brumfield, and J.R. Stewart. 2014. Biocontainer use in a Petunia ×hybrida greenhouse production system: A cradle-to-gate carbon footprint assessment of secondary impacts. HortScience 49:265-271.

Li, T., G. Bi, G. Niu, S. Nambuthiri, R. Geneve, X. Wang, T. Fernandez, Y. Sun, and X. Zhao.2015. The feasibility of using biocontainers ina pot-in-pot system for nursery productionof river birch. HortTechnology 25:57-62.

Lopez, R.G. and D.M. Camberto. 2011. Growth and development of ‘Eckespoint Classic Red’ poinsettia in biodegradable and compostable containers. HortTechnology 21:419-423.

Nambuthiri, S., A. Fulcher, A. Koeser, R. Geneve, and G. Niu. 2015. Moving towards sustainability with alternative containers for greenhouse and nursery crop production: A review and research update. HortTechnology 25:8-16.

Nambuthiri, S., R.L. Geneve, Y. Sun, X. Wang , R.T. Fernandez, G. Niu, G. Bi, and A. Fulcher. 2015. Substrate temperature in plastic and alternative nursery containers. HortTechnology 25:50-56.

Nambuthiri, S., R. Schnelle, A. Fulcher, R. Geneve, A. Koeser, S. Verlinden, and R. Conneway. 2013. Alternative containers for a sustainable greenhouse and nursery crop production. Univ. Kentucky Coop. Ext. Serv. HortFact-600.

Privett, D.W. and R.L. Hummel. 1992. Root and shoot growth of ‘Coral Beauty’ cotoneaster and leyland cypress produced in porous and nonporous containers. J. Environ. Hort. 10:133-136.

RootPouch. 2015. RootPouch frequently asked questions. 17 April 2015. rootpouch.com/faq

Ruter, J.M. 1999. Fiber pots improve survival of ‘Otto Luyken’ laurel. Proc. Southern Nursery Assn. Res. Conf. 44:37-38.

Ruter, J.M. 2000. Biodegradable fiber containers improve the growth of two daylily cultivars. Acta Hort. 517:271-274.

Schrader, J., G. Srinivasan, D. Grewell, K. McCabe, and W. Graves. 2013. Fertilizer effects of soy-plastic containers during crop production and transplant establishment. HortScience 48:724-731.

Sun, Y., G. Niu, A. Koeser, G. Bi, V. Anderson, K. Jacobsen, R. Conneway, S. Verlinden, R. Stewart, and S.T. Lovell. 2015. Impact of biocontainers on plant performance and container decomposition in the landscape. HortTechnology 25:63-70.

Wang, X. 2013. Irrigation management and alternative containers for more sustainable nursery production. Mich. State Univ., East Lansing, MS thesis.

Wang, X., R.T. Fernandez, B.M. Cregg, R. Auras, A. Fulcher, D.R. Cochran, G. Niu, Y. Sun, G. Bi, S. Nambuthiri, and R.L. Geneve. 2015.Multi-state evaluation of plant growth andwater use in plastic and alternative nurserycontainers. HortTechnology 25(1):42-49.

This publication series was possible due to support from the USDA Specialty Crop Research Initiative project No. 2010-01190 and the University of Tennessee Institute of Agriculture.

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W 337-A 11/15 16-0010Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and

resource development. University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.