I use a bark-based mix that I buy in bulk from a local wholesaler for both container plantings and to build raised beds. The wholesaler claims that they add nitrogen to the bark to overcome its tendency to take nitrogen from the soil. Unfortunately, after years of using this product, it is obvious now that they are not doing this. Plants that go into this soil show clear signs of nitrogen deficiency that gets worse and worse over time.

If I want to try to remediate the problem and rescue plants in this soil that are already very nitrogen-depleted, what is the best strategy? Do I just start to fertilize with organic fertilizer and wait for the soil to recharge, or should I be complementing the organic fertilizer with some liquid synthetic fertilizer, just to immediately treat the plants and get them to start growing again?