I recently read a NY Times article about straw bale gardening. It says that you should add about 2 1/2 cups of 20% N fertilizer or three pounds of blood meal and feather meal per bale. Add water, wait for the temperature to decrease, and then plant.
I would really appreciate a more objective approach - but I can't find it in any of the guides (including the few instructions from ag extensions*) that I reviewed.
What I am missing is the target range of C:N for the bale - for a mixture of vegetables (tomatoes, squash, beets, carrots) as seen in the article. Then, I could better estimate - and evaluate - what I am doing.
If I knew the target C:N ratio, and how to account for the uneven decomposition and N loss (leaching, denitrification) as well as the "tolerance" for over / under fertilization (i.e., the range of applications rates that would optimize food production), then I could take an arbitrary fertilizer with complete nutrition (NPK+) and have an estimate of how much to add based on the % N.
in summary, my questions are:
- What is the target C:N for a straw bale garden?
- How much fertilizer should I add, in units of mass (g or lb) N?
- What is the range of values in 1 and/or 2 that would optimize mixed vegetable food production?
* for example, while the OKState extension says "The nutrient supply for plants established in straw bales is also critical." but gives no information on fertilization rate, only that insufficient nutrient supply can be be diagnosed (yellow leaves, unhealthy plants, etc.).