are those clay balls just for growing with a drip system or can you actually grow in the clay balls like a soil medium? i saw someone on another sight using them and said they like them better than soil because there is no mess.. i thought you had to use a drip method of watering or some sort of hydro setup when you use the balls tho. i would think plain watering would just wash through the pellets, unless they retain water.. anyone have exp with this?