Potatoes, peas and corn – plant them in that order.
Commercial grade fertilizer has 3 numbers, such as 13-13-13. Those three numbers stand for nitrogen, phosphorus, and potassium (also called Pot Ash).
nitrogen – large leaves, tall growth – greens, spinach, corn, okra
phosphorus – root growth – potatoes, turnips
potassium / pot ash – pod production – peas, beans, corn, okra, squash
Potatoes – use fertilizers with a high middle number, such as 10-20-10 fertilizer. The higher phosphorus content helps promote root growth. The potatoes can be harvested and eaten at anytime. Just dig around the base of the potato plant and pull out the potatoes when you want some to cook. Or, wait until the top of the plant dies, then you know the potatoes are full grown and ready to harvest.