Internal walls of containers can be
coated with copper compounds such as Spin Outwhich is a latex-based paint containing copper hydroxide
and a special formulated carrier (Figs. 3–23 and 3–25)
that enhances root absorption of copper and temporarily
inhibits root elongation (115), or containers can
have special wall modifications as a means to reduce or
prevent root circling during liner production and later
container production. As shown in Figure 3–36, plants
not properly air root-pruned or that are kept in containers
too long will form an undesirable constricted root
system from which they may never recover when
planted in their permanent location. The plants should
be shifted to larger containers before such “root spiraling”
occurs.