Concentration dependence of the nuclear longitudinal and transverse relaxation times T1 and T2 are theoretically studied for solid H2 with dilute ortho-H2, by extending the previous treatment by Hama et al. The effect of crystalline field energies is taken into account by confining EQQ Hamiltonian to its secular part in crystalline field frequency. The results for T1 are shown to be in good agreement with experiments at ortho concentrations down to 3 ×10-3. The results for T2 are presented for the twolimiting cases of low and high rotational Zeeman frequencies where the high frequency limit is relevant to the case of very low concentrations, in agreement with experiments. The continuum approximation used throughout the present study is shown to break down at concentrations lower than frequency-dependent critical values, being in accord with the concentration at which theoretical deviations from experiments begin to occur for T1 at 30 MHz.