Assists in producing longitudinal or profile plots of measured traits. These allow checks to be made for anomalous data and growth patterns in the data to be explored. Smoothing of growth trends for individual plants using smoothing splines is available for removing transient effects. There are tools for diagnosing the adequacy of trait smoothing, either using this package or other packages, such as those that fit nonlinear growth models. A range of per-unit (pot, plant, plot) growth traits can be extracted from longitudinal data, including single time-point smoothed trait values and their growth rates, interval growth rates and other growth statistics, such as maximum growth. The package is particularly suited to preparing data from high-throughput phenotyping facilities, such as imaging data from a Lemna-Tec Scananalyzer (see < https://www.lemnatec.com/products/conveyor-scanalyzer/> for more information). The package 'growthPheno' can also be installed from < http://chris.brien.name/rpackages/>.