From Wood Box to Plastic Container 24"/#25 & 36"/#45

Printable PDF Box Size to Container Size Equivalents

Wholesale nurseries throughout the southwest are replacing wood boxes in favor of plastic containers for growing specimen landscape trees. Growers in the southeastern have successfully using plastic containers for decades to produce a wide assortment of landscape trees. Arid Zone Trees (AZT) began experiments with plastic containers after consulting the research literature, speaking with national/local landscape horticulture professionals, and design community clients. Like other local growers, we are building on the work of other early adopters to develop methods for growing desert-adapted trees in these containers. The positive reception from clients (landscape architects and contractors) has convinced an ever-increasing number of Arizona growers that they are a viable alternative to boxes. To facilitate this box to container conversion growers who ship outside of Arizona follow the standards established by American Horticulture Industry Association (d/b/a AmericanHort an ANSI-accredited Standards Developing Organization).

We based our container selections on 5 critical criteria: 1) that the plastic containers selected be well researched and had been extensively field evaluated in conditions similar to desert growing methods; 2) they would readily integrate with our ongoing production quality controls at AZT; 3) that they compliment and amplify the effectiveness of our Root Management Program; 4) that they maintain a physical profile, sufficiently similar to boxes, so that landscape architects would not need to revise their planting specifications and that contractors would not need to make costly modifications to their planting methods; and 5) since, like other growers, we ship to states other than Arizona, we wanted our trees to adhere to a nationally recognized standard.

American National Standard Institute (ANSI) is a federation of organizations, associations/societies, governmental agencies and international bodies. The ANSI Standards addressed our national distribution concerns and had the added benefit of having been in existence for decades (the first “Horticultural Standards” were published in 1923) and were regularly reviewed and revised (as needed) by a board consisting of nursery professionals. Revisions are submitted to a list of horticulture-focused societies, associations, companies, individuals, and related government agencies for “evidence of industry consensus” for meeting ANSI requirement for accredited national standards. These standards, for plastic containers, allow growers, like AZT, to grow and sell premium quality trees that are compatible with the design and planting practices that landscape architects and contractors have come to expect from our trees and allow us to distribute those trees to a national market.

Due in part to their weight, height, and width, we still grow specimen desert tree in 48” boxes. We continue to evaluate innovations in plastic containers that are introduced to determine if they better meet our original 5 criteria. We will keep you updated on any developments.

For purposes of Table 1, box size “equivalent” indicates that a box size may be specified in lieu of the indicated equivalent container class, and nursery stock in an equivalent box size shall be accepted in the trade as in conformance with a specification for container-grown nursery stock in the equivalent container class indicated, and vice-versa. Boxes are not required to have volumes that are “equal to” or within the volume range of the indicated equivalent container class, or vice-versa.

Table 1

American Standard for Nursery Stock Box Size to Container Size Equivalents

1.1.3.7 Box size equivalents

Container Class Specification to Box Size Equivalent

# 20 = 20-inch box

# 25 = 24-inch box

# 45 = 36-inch box

# 65 = 42-inch box

# 95/100 = 48-inch box

Complete PDF of The American Standard for Nursery Stock 2014 edition ANSI Z60.1-2014 is available at www.americanhort.org/page/standards

Reprinted with permission from AmericanHort. www.AmericanHort.org

an ANSI-accredited Standards Developing Organization