rocks in the bottom is done for mainly the same reason people put newspaper in the bottom.
to prevent the soil from escaping though the bottom holes.
if the peat moss is so absorbant, why not just use less of that and more of some of the other mediums?
probably perlite if you are having real problems.
drilling holes in the sides, does work somewhat, or at least i think so lol, but can be bit problematic when you water, gotta water slow or sometimes the water shoots out the holes (usually bit further than the tray..)
to prevent the soil from escaping though the bottom holes.
if the peat moss is so absorbant, why not just use less of that and more of some of the other mediums?
probably perlite if you are having real problems.
drilling holes in the sides, does work somewhat, or at least i think so lol, but can be bit problematic when you water, gotta water slow or sometimes the water shoots out the holes (usually bit further than the tray..)