We live on a neutral sandy soil. Plants have not done well directly in soil. Very hard to keep PH down as sulfur compounds tend to leach quickly in sandy soil.
What is working for me, is pretty similar to what you have above. In a raised bed, I mix sandy soil with compost, sphagnum peat and partially composted pine bark fines. The compost tends to be alkaline so it may require some sulfur initially to fine tune the pH.
Then I mulch on top with a combination of pine bark, peat and compost. I generally don't need to fertilize with this combination, but still need to keep an eye on the PH due to the compost. Once the pH is stable the peat and bark tend to maintain it until I add more compost.
Sounds like you've got a great system worked out.
Sometimes it takes a bit of experimentation to find what works best for our particular soil. Soils can change rapidly over the course of a short distance, so what works well for someone who lives close by may not work well for ourselves.
Having the basic knowledge of what a given plant needs is a necessary starting point, but often it takes some fine-tuning to achieve the desired results.
Your experience may be very helpful for someone who wishes to grow blueberries in a soil similar to yours.
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