I wouldn't bother. For anything to become a nutrient, it has to be broken down to the molecular level that roots can absorb. Any material that's like fruit peel would have to undergo complete rotting to be effective. That's why companies make hydro ferts - they work and do so quickly. A good example would be a compost pile in that it takes time for large organic bits to be broken down by bacteria so it can be used as a fertilizer. Hydro is much cleaner and pretty easy provided you stay as soluble as possible.