The basal quick-dip is the most popular method of auxin application in nursery
propagation. Historically, commercial propagators have found quick-dips to be
the quickest and most economical method as a limited amount of material can be
applied directly to the basal region of the cuttings where adventitious root initiation
and development will take place. The concentration of the auxin formulation
can be modified to produce optimal rooting of the cuttings. Powders are the next
most common method of applying auxins, but propagators are limited to certain
concentrations. Some propagators may subject cuttings to an extended basal soak,
which typically requires the bundling of cuttings along with additional time and
space for the treatment process. Other methods of auxin application that have been
investigated include forced entry of auxins into cuttings using a vacuum, insertion
of auxin-treated objects (such as toothpicks) into the cutting base, immersion of cuttings
in an auxin solution for varying lengths of time, and treatment with auxins in
a lanolin base (Blazich, 1988). Some of these uncommon methods remain of interest
in the history of cutting propagation, while others still find use under certain
circumstances with specific crops.