My husband and I have a large, deep planter box that we filled with bagged soil last year. Last year, we planted a number of seeds, which sprouted beautifully but then failed to grow further/thrive. I tested the soil with a home test kit, and it showed a surplus of phosphorous. So, we replaced most of the soil in the box, but when I tested again this year, the phosphorus level is still showing up as “surplus.” (Perhaps this is a problem with Alaska soil?) Are there any steps I can take short of replacing the soil (which is time consuming and expensive) that would help address this issue? Nitrogen and potassium levels are normal, and pH is a bit high (~7.5), but not crazy.