MCR Labs is a cannabis testing lab based in Framingham that has been in operation since 2013. The lab recently engaged in an experiment where they studied both indoor and outdoor cannabis to see whether each method results in different outcomes. Five strains were grown, dried, and tested as part of this experiment. MCR Labs used a targeted quantitative analysis to measure cannabinoids, terpenes, and heavy metals. A second lab named SCIEX used an untargeted qualitative approach.
The results of the experiment showed that in all cases cannabis plants grown outdoors had higher terpene levels. Outdoor plants also had higher THCa levels on average. When it comes to heavy metal contamination the data showed that two indoor samples contained cadmium while the outdoor samples did not.
Find the full breakdown of the experiment from MRC Labs here: https://blog.mcrlabs.com/outdoor-vs.-indoor-grows-how-the-growing-environment-affects-the-chemical-makeup-of-cannabis