I have never done that either. But I do make sure the mix is evenly moist all throughout by wetting it then heating it in the microwave for a few minutes, stir it around, then heating a again. The steam does wonders to penetrate a mix that resists wetting. This year I used a 50/50 (approximately) blend of Black Gold potting soil and Black Gold seedling mix (milled Canadian sphagnum peat moss and perlite).
