W 337-A

BEYOND PLASTIC POTS

Part 1: Compostable, Plantable and Other Containers for Nursery Crop Production Quinn Cypher, Extension Associate Amy 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.

Environmental sustainability or being Most ornamental plants are produced and “green” has gained a foothold in a wide sold in conventional, petroleum-based range of consumer products, from organic plastic containers made from nonrenewable foods to energy-efficient lightbulbs to resources. These products can be recycled eco-friendly packaging. Such sustainable or reused, but recycling is not always alternatives are widely available and generally available, and reusing containers increases bring a price premium. The green industry the risk of disease outbreaks. Therefore, has many opportunities to advance the many used nursery containers end up in environmental sustainability of production, the landfill or in a nursery storage area. including adopting Integrated Pest Alternative containers are not new, but Management, enhancing water use efficiency, never have there been so many options. reducing pesticide use and runoff, and With the recent development of more than improving energy efficiency. These steps 10 types of alternative containers, it is likely are not often visible to consumers, and, that there is an option suitable for almost therefore, are not as easy to market. every nursery or greenhouse operation. However, one highly recognizable opportunity is alternative containers.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 1 Switching from petroleum-based plastic containers to an eco-friendly alternative is Compostable a highly visible means to meet consumer Containers demand for sustainable products while capitalizing on a consumer’s willingness Compostable containers are made from to pay for eco-friendly products, including materials that will decompose when the alternative containers. It is not only plant is removed and they are composted. possible to produce an equivalent product Containers made from rice hulls, PLA using alternative containers — it may be (polylactic acid), recycled paper and/ advantageous in certain situations. Waste, or cardboard are currently available nonrenewable resource use and the overall commercially. Soy, corn, bamboo, poultry carbon footprint of ornamental crops can feathers, wheat starch and other natural be reduced through the use of alternative fiber waste products have been used containers. Environmental sustainability to make compostable containers and and carbon footprint concerns have driven may become available commercially as the development of three categories the demand for biocontainers grows. of alternative containers: compostable, plantable and other alternative containers that we refer to in this series as R3 containers. R3 Containers R3 containers are composed of recycled plastic and/or bio-based plastic, can often (Recycled Plastic be recycled, and are suitable for reuse. They and/or Bio-based can have rigid sidewalls like a traditional nursery container or be collapsible due Plastic Containers) to their geotextile fabric construction. Containers in this class are made from either Compostable and plantable containers recycled plastics or a blend of petroleum- are broadly referred to as “biocontainers” based plastics, bioplastics and natural as they are made from biodegradable fibers. Typically, these containers can be materials. These three categories are used reused and/or recycled. Containers in this here for clarity and are not absolute. For class can be made to mimic the form and example, some R3 containers will degrade, function of conventional plastic containers while some compostable fiber containers or provide an alternative such as a fabric could be planted if aged or if the sides container. Although fabric containers made are cut. Most of the available alternative from recycled plastic and natural fibers do containers have been researched thoroughly, not decompose, they will disintegrate over and this resource along with referenced time due to the natural fiber component. information will allow growers to make informed decisions regarding adopting compostable, R3 and plantable pots.

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

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

Figure 3. Plantable container Fig. 1 (photo credit: Diana Cochran)

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

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

Alternative containers have a variety of Water Use section below), the majority have characteristics that can aid production. concluded that alternative containers provide Container type can influence plant growth acceptable plant growth and appearance. through the effects of porous sidewalls As long as the correct container type is (i.e., higher water use, reduced root circling, chosen, a nursery should be able to easily and by supplying nitrogen to the plants as produce a product that can compete with they decompose). Alternative containers one grown in a conventional container. can improve growth, and several studies Plant size, health, vigor and appeal of have shown the potential to increase shoot the entire finished product (including the biomass, root biomass and overall growth. container) can be matched or exceeded Although a few studies have shown reduced using the appropriate alternative container. growth in some alternative containers (see

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

In some alternative containers, it may be Water use in above ground outdoor necessary to increase the frequency and/or production using alternative containers volume of irrigation to produce a crop that is impacted by weather and varies with is equivalent to one grown in a conventional location. Higher container porosity generally plastic container. Alternative containers have results in higher water loss. For example, varying degrees of porosity, which impacts 1-gallon coir containers used 1.2-1.4 times water loss through the sidewalls. Water loss more water in Kentucky, Mississippi and must be taken into account when making Texas compared to conventional black plastic the switch to plantable containers because containers but used equivalent irrigation in watering regimes used with plastic containers Tennessee, likely due to higher rainfall that can result in decreased plant growth. season. Generally, pots made out of bio- Plantable pots have the highest water loss plastic and solid rice hulls (compostable rates through their sidewalls and can require containers) require about the same volume 1.4 to 2.6 times more water for greenhouse and frequency of irrigation as plastic pots. crops compared to black plastic containers. While greater container porosity generally

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 5 leads to higher water requirements, high temperatures also influence crop Container Strength water requirements in outdoor nurseries. during Production Nonporous containers made from keratin (currently not available commercially) used and Transport less water than conventional black plastic To be viable, alternative containers must be containers, likely due to their light color. able to withstand the production process, Therefore, it is possible for biocontainers loading and transportation, as well as to outperform plastic containers in terms endure an unpredictable amount of time in of water use. The irrigation application a retail setting. Alternative containers have technique used may also affect water varying strengths depending on material requirements. For example, using an ebb- and manufacturing process and are suited and-flood system with 1-gallon bioplastic, for different crops. Compostable containers solid rice hull, slotted rice hull, paper and are generally stronger and perform well coconut fiber containers all had similar in production cycles of up to one year. water requirements. Many options are Plantable containers are typically weaker available to reduce water consumption than compostable and recyclable containers, including shuttle trays that cover the with the notable exception of the slotted porous sidewalls of containers, pot-in- rice hull and coir containers (plantable pot production, substrate amendments containers with high strength). Plantable and optimized irrigation scheduling. containers are likely best suited for annual bedding crops, vegetables, and single-season production cycle perennial and woody crops. Water use research presented in this series is narrowly focused on comparing container type. Growers Because plantable containers are designed interested in conserving water have options when to decompose in the landscape, depending considering their overall operation. For information on the material and the weather these on water conservation and sustainable irrigation, containers may begin decomposing in the see Extension publications W 278-W 280: nursery. Certain containers in this group can Sustainable Nursery Irrigation Management Series, also grow algae during nursery production. 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

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 6 increased cost after adopting nonreusable The Bottom Line alternative containers; however, storing — Economics of and sanitizing old containers and the labor and cost associated with those tasks Alternative Containers would be eliminated. Most of the changes Switching from plastic containers to in costs are marginal, suggesting that if alternative containers affects the cost of the additional cost of the container can be different stages of production, making the offset by an increased sales price, alternative question of “How will this affect my profit containers become an economically viable margin?” somewhat challenging to answer. alternative. Each of the three classes of 3 The two biggest factors influencing the containers (compostable, R and plantable) profitability of alternative containers are the will have a different effect on production cost of the container and the ability to charge costs and sale price and are addressed a premium price for the product. Typically, specifically in Parts II and III of this series. alternative containers are more expensive than plastic pots; however, the prices for Several studies have attempted to quantify both fluctuate. Also, many alternative the value that consumers place on alternative containers are relatively new, and the price containers and have concluded that they will likely fall as their availability increases. are often willing to pay a premium price for alternative containers. Generally, consumers Changing container types has the potential are likely to pay the highest price premium to affect both the production costs and for compostable containers, followed by sale price of the product, and each type of recycled and/or plantable depending on container will have a different effect. The their attitude toward the environment. In factors influencing the cost of production an experimental auction where real money include the price of the container, potential and product exchanged hands, consumers changes in water use, changes in production were willing to pay 58 cents more for time, potential decrease in portability, chrysanthemums in 4-inch rice hull pots, 37 potential changes in fertilizer use, and cents for straw pots and 23 cents for wheat increase in sale price due to consumer starch pots when compared to 4-inch plastic willingness to pay more. Additionally, some pots. As of 2015, the price of a 4-inch rice hull alternative containers are somewhat larger pot was 12 cents, and an equivalent plastic or smaller than their conventional petroleum- container was 7 cents; therefore, the price based plastic counterparts, which may premium needed to recoup the additional alter the amount of substrate, fertilizer, cost was minimal — just 5 cents per container pesticides and water, as well as shipping (prices will vary by quantity purchased costs (for receiving new containers and and supplier). The price premium may not shipping out finished plants). Nurseries that stand in all markets and will likely depend typically reuse their containers would see an on the type of sale (commercial or retail) and the volume (flats or individual plants).

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 7 For flats of groundcover plants, large Compostable, R3 or commercial buyers were more likely than Plantable — Which small companies to buy plantable over plastic containers. Most retail consumers is Right for You? didn’t prefer flats of groundcover plants in Alternative containers are a highly visible plantable containers over plastic; however, means to “green” the green industry and older consumers and consumers with children a wide variety of containers are available. did. (Note: Retail customers surveyed for Not only can a competitive product be container preference of groundcovers were produced, but alternative containers can be a subset of customers from a single garden beneficial during production and marketing. center and not necessarily representative Meeting consumers’ demands for green of retail customers at large.) In a related products will improve the environmental study, the time to install (not including job sustainability of the nursery industry, site cleanup and used container disposal) can be economically advantageous, was 20 percent faster for groundcovers and can be achieved with proper in plantable containers, underscoring alternative container selection and use. 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 Caution

As 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.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 8 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.

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

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Evans, M.R., A.K. Koeser, G. Bi, S. Nambuthiri, R. Khachatryan, H., B. Campbell, C. Hall, B. Behe, C. Geneve, S.T. Lovell, and J.R. Stewart. 2015. Impact of Yue, and J. Dennis. 2014. The effects of individual biocontainers with and without shuttle trays on water environmental concerns on willingness to pay for use in the production of a containerized ornamental sustainable plant attributes. HortScience 49:69-75. greenhouse crop. HortTechnology 25:35-41. Koeser, A.K., G. Kling, C. Miller, and D. Warnock. 2013. Compatibility of biocontainers in commercial greenhouse crop production. HortTechnology 23:149-156.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 10 Koeser, A.K., S.T. Lovell, M.R. Evans, RootPouch. 2015. RootPouch frequently asked and J.R. Stewart. 2013. Biocontainer questions. 17 April 2015. rootpouch.com/faq water use in short-term greenhouse crop production. HortTechnology 23:215-219. Ruter, J.M. 1999. Fiber pots improve survival of ‘Otto Luyken’ laurel. Proc. Southern Koeser, A.K., S.T. Lovell, A.C. Petri, R.G. Brumfield, Nursery Assn. Res. Conf. 44:37-38. and J.R. Stewart. 2014. Biocontainer use in a Petunia ×hybrida greenhouse production system: Ruter, J.M. 2000. Biodegradable fiber A cradle-to-gate carbon footprint assessment of containers improve the growth of two secondary impacts. HortScience 49:265-271. daylily cultivars. Acta Hort. 517:271-274.

Li, T., G. Bi, G. Niu, S. Nambuthiri, R. Geneve, Schrader, J., G. Srinivasan, D. Grewell, K. X. Wang, T. Fernandez, Y. Sun, and X. Zhao. McCabe, and W. Graves. 2013. Fertilizer effects of 2015. The feasibility of using biocontainers in soy-plastic containers during crop production and a pot-in-pot system for nursery production transplant establishment. HortScience 48:724-731. of river birch. HortTechnology 25:57-62. Sun, Y., G. Niu, A. Koeser, G. Bi, V. Anderson, K. Lopez, R.G. and D.M. Camberto. 2011. Growth Jacobsen, R. Conneway, S. Verlinden, R. Stewart, and development of ‘Eckespoint Classic Red’ and S.T. Lovell. 2015. Impact of biocontainers on poinsettia in biodegradable and compostable plant performance and container decomposition containers. HortTechnology 21:419-423. in the landscape. HortTechnology 25:63-70.

Nambuthiri, S., A. Fulcher, A. Koeser, R. Geneve, Wang, X. 2013. Irrigation management and and G. Niu. 2015. Moving towards sustainability alternative containers for more sustainable nursery with alternative containers for greenhouse production. Mich. State Univ., East Lansing, MS thesis. and nursery crop production: A review and research update. HortTechnology 25:8-16. Wang, X., R.T. Fernandez, B.M. Cregg, R. Auras, A. Fulcher, D.R. Cochran, G. Niu, Y. Sun, Nambuthiri, S., R.L. Geneve, Y. Sun, X. Wang , G. Bi, S. Nambuthiri, and R.L. Geneve. 2015. R.T. Fernandez, G. Niu, G. Bi, and A. Fulcher. 2015. Multi-state evaluation of plant growth and Substrate temperature in plastic and alternative water use in plastic and alternative nursery nursery containers. HortTechnology 25:50-56. containers. HortTechnology 25(1):42-49.

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. 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.

BEYOND PLASTIC POTS | Part 1: Compostable, Plantable, and Other Containers for Nursery Crop Production 11 W 337-A 11/15 16-0010 Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and BEYOND PLASTICresource POTS development. | Part 1: Compostable,University of Tennessee Plantable, Institute and Other of Agriculture,Containers forU.S. Nursery Department Crop of Production Agriculture and county 12 governments cooperating. UT Extension provides equal opportunities in programs and employment.