<p>The presence of bedding planes (BPs) in shale gas reservoirs is considered as one of the main factors for contained hydraulic fracture (HF) height and understanding this mechanism is still open. In this paper, HF crossing BPs is modeled as nucleation of a new fracture at BP interface based on the dual criterion, which satisfies simultaneously a strength and a toughness condition. The fracture-nucleation size (FNS) is generated to allow subsequent fracture growth on the opposite side of the BP. Using a two-dimensional fracture-nucleation model, the small, finite FNS was first obtained through a predictor–corrector method against the known results for fracture growth in homogeneous rocks and shows its dependence on the rock properties and stress conditions. It was then employed in case studies with numerical results showing how the BP conditions affect the progressive growth of a nucleated fracture. The growth of an HF crossing BPs occurs with an intermittent growth speed. Under a vertical stress level of 100 MPa, the FNS is 2 mm, and numerically, this causes large computational cost and requires adaptive element sizes. When the BP aperture characterizing its pre-existing fluid conductivity is less than 10^–7 m, the fracture crosses the BP, while for a BP aperture of 10^–5 m, the fracture deflects into the BP. HF crossing becomes more difficult after it penetrates more layers and the modeled fracture height is comparable to that inferred from microseismic measurements. The difficulty in fracture nucleation can provide a useful model for height growth and containment.</p>