This report introduces a quasicontinuum formulation for heterogeneous granular systems. The description assumes that the relative displacements between particles are described by a constrained field while the interparticle forces are resolved locally. Equilibrium is enforced weakly by virtue of the principle of virtual displacement, The methodology accounts for particles of variable size and different species. Interaction forces between particles in different cells are computed using a rule which allows for local operations and renders symmetric tangent operators. Energy relaxation from static condensation of an internal node is proposed as an indicator for adaptive meshing, Simulations of uniaxial densification show the robustness and versatility of the formulation for heterogeneous granular beds. The numerical tests also recover the general trends observed in compaction experiments.