A steady state eddy diffusion model is developed for estimating the vertical distributions of radon progeny activity, progeny/parent ratios, unattached fraction and equilibrium factor within and above homogeneous vegetation canopies, and for evaluating the deposited activity onto vegetation. Turbulent diffusion coefficient profiles are tailored to account for the slowing down of turbulent transport within the canopy. Progeny are divided into two classes: attached and unattached to aerosol. Dry deposition is included as a distinct term in the turbulent diffusion equation rather than in the lower boundary conditions. Surface available for deposition is explicitly taken into account. Model predictions are compared with available experimental data collected in and above a wheat field. The model successfully explains experimental trends such as progeny/parent ratios greater than 1 and high gradients of unattached fraction. ¿ 1999 American Geophysical Union