tapla wrote: It doesn't matter what you use to measure the ingredients. The measurements are by volume, so a cup, a gallon, or a 5 gallon pail of each will yield the same soil. I keep several bushels of screened ingredients on hand at all times so I can make any size batch I want. With around 200 bonsai, most requiring yearly repotting, plus all my other plants, you can see that I go through a LOT of soil. I usually add about 2 gallons of each ingredient to a masonry mixing trough, mix thoroughly, pour the mixed soil into a trash can, and then go on to mix the next batch.