The penetration power of the roots into the soil has been studied in relation to field crops but not to container media. In this work the mechanical impedance of sand, perlite, peat, coir and commercial mixtures were evaluated: Fafard, no 2, Fafard 2P, Jiffy 7 and Oasis. Dry and saturated samples were analyzed under four levels of compactation. Jiffy 7 and Oasis were analyzed only in the original density of the manufactured products. The impedance was measured by a metal probe and a digital micropenetrometer. The penetration pressure is correlated to the level of compactation of the media, with significant interaction between compactation and moisture level.
