Bamboo Potting Mix
I am about to plant Phyllostachys aureosulcata Spectabilis in containers. The containers are six feet long, one foot wide, and two and a half feet deep.
So, my first question is should I fill the entire depth of the planter with potting mix? Will the bamboo roots make use of the space? My thinking is that the planter is so narrow, that the roots will need all the space they can get, so I should just fill it up with just a small layer of rocks at the bottom.
Second, I am hoping what I am using as a medium will be okay. I purchased a bunch of products, and my mix is the following:
1 part topsoil (Agway house brand)
1 part compost (Agway house brand)
1 part potting soil (Agway house brand)
2 parts Pro Mix BX
1/2 part (maybe even less) composted Pine Bark Mulch (I am just taking the old bits of bark from the underlayer in my garden, since I wasn't able to find pine bark fines).
1 handful of Ringer Lawn Restore (organic fertilizer)
Will this be suitable for my bamboo?
I was thinking that I could make the lower portion of the container more topsoil heavy and lighten up on the topsoil for the upper portion, but then I don't want poor drainage anywhere, so I'll spend the extra couple bucks to keep the media the same the whole way through.