As garden vegetables grow, they undergo an intensive process that strips nutrients from the soil. Adding fertilizer keeps soil in optimum shape to feed your … Figure 1. This bag contain 13 percent nitrogen, 13 percent phosphorus, and 13 percent potassium (or potash). Figure 2. Take soil samples from several areas of the garden and mix them together. Figure 3. Use 2 to 3 pounds of fertilizer such as 10-20-10 for every 100 square feet of garden area. Figure 4. Figure 5. Different edible plants need different fertilizing plans to help them grow strong, healthy, and fruitful. Here’s a guide to fertilizing your vegetables. Very handy vegetable fertilizer chart. Includes dosage, amount per plant, and pertinent notes. I understand that some fertilizers promote root growth, some promote leaves, and some encourage flowering. I have fish emulsion and a seaweed solution.