The biological process of tobacco leaf ripening is one of senescence. In commercial tobacco growing (in soil, in the sun), fertilizer is usually applied once, prior to transplanting to the ground, and sometimes reapplied at half-strength after a heavy rainfall during the first 2 weeks after transplant. The logic in not fertilizing during the last 4 to 8 weeks prior to harvest is to encourage leaf senescence. Translating that guidance to container growing in non-soil media, and in artificial light, becomes a trial and error experiment.
This differs from food gardening for leafy greens, where you aim to harvest edible leaf at its most robust biological state.
Bob