Limiting solid growth barriers across the protoplanetary disk for our fiducial model. Stokes number limited by fragmentation from Eq. (15), indicated by the green line, and limited by the radial drift from Eq. (16), indicated by the blue line (top). The red dashed-dotted line illustrates initial St when we set constant Stχ ≡ St ⋅ χ (see Sect. 2.3). Initial particle size for each growth barrier from Eq. (14), indicated by the dashed lines, and the growth timescale for reaching the corresponding size from Eq. (17), indicated by the solid lines (bottom). The dotted gray lines denote St ≈ 0.03 and τ_g ≈ 0.2 Myr at R₁ = 100 AU set by radial drift.