Reading the information on E. B Stone mix, I see it is a mix of 6 ingredients. Normally a mix should be made from no more than three ingredients, four at the very most, I don't like a mix with both lava rock and pumice as is in E.B. Stone, plus you additionally add 50% more pumice . Personally I would not incorporate ether of them in any mix that I would use. Rapidly developing roots of seedlings with high respiration rates require oxygen levels greater than old plants. When plants are watered excessively, the amount of oxygen diffusing to the root system is decreased. The amount of carbon dioxide, on the other hand, is increased since the carbon dioxide comes from the living roots, bacteria and fungi. If the carbon dioxide content alone reaches too high a level it can be toxic and cause the deterioration of roots of plants in containers. Because the column of growth medium is not continuous as soil is under field conditions, the water accumulates at the bottom of the container. This restriction of downward flow of water occurs in a container with no bottom or with wire bottoms as well, since the drainage column is broken. Therefore, the more shallow the container, the less growth medium in the top portion of the container that is well drained and suitable for good root growth. The more shallow the container, the more porous the growth medium must be Likewise the deeper the container the smaller the pores can be within reasonable limits. The desirable combination is a moderate depth container with a growth medium of moderate texture. The drainable pore space for tree seedlings should be 25% to 35%. Growth media that have worked well are 1:1 peat and perlite; 2:1:1 ground pine bark, peat and perlite, or 2:1:1 ground pine bark, peat and vermiculite.