This dataset is associated with the article authored by Marine Pacé, David Paré, Nicole Fenton and Yves Bergeron entitled "Effect of lichen, Sphagnum spp. and feather moss leachates on jack pine and black spruce growth ". It includes growth surveys of jack pine and black spruce in greenhouse at different stages of development (0-6 month-old and 2 year-old seedlings). Seedlings were subjected to different types of leachates: jack pine was subjected to control (bare soil), feather moss and lichen leachates; black spruce was subjected to control (bare soil), feather moss and Sphagnum spp. leachates. The donor species (feather mosses, lichens, Sphagnum spp. mosses) and the target species (jack pine and black spruce) were contained in different pots connected by a polyethylene tube. The dataset also contains information on the chemical composition of the substrate contained in the target pots at the end of the experiments (N, P, K, Ca, Mg, Mn, Al, Fe, Na), on the ectomycorrhizal colonization of jack pine seedling roots, and on the chemical composition of the leachates (N, polyphenols and usnic acid).