Will this tank need fertilizer for the plants, or should i only trust the soil to give enough fertz to the plants?
In a planted tank with fish, the soil layer is replenished through the fish feeding cycle. But without fish and you are not dosing fertilizer, nutrients from the soil will run out sooner or later. And you will have to replace the soil. Nothing will provide indefinite supply without replenishment.
BTW, if the plants are in individual containers, you can replant only those showing nutrient deficiency.