Apply a balanced fertilizer at the time of planting to prevent the zucchini seeds or transplants from burning up from excessive amounts of nitrogen. Use a fertilizer that has a NPK amount of 8-8-8 or 10-10-10, as recommended by North Carolina State University. NPK refers to the percentage of nitrogen, phosphorous and potassium found in the fertilizer bag. You can check the bag's label to find out how much of each nutrient is found in the fertilizer.
How to Apply
Apply half of the recommended amount over the area and till the fertilizer into the first 3 to 4 inches of topsoil. The other half of the fertilizer should be applied just below seed level in the furrows of the garden. The furrows are the raised dirt areas between rows. This practice is referred to as banding. Typically, gardeners will apply 20 to 30 lbs. of fertilizer at the time of planting per 1,000 square feet, according to North Carolina State University.
Sidedressing fertilizer means that you apply the nutrients 4 to 6 inches away from the plant on both sides of the vegetable rows, according to North Carolina State University. Gardeners sidedress their zucchini plants after the seedlings have emerged to provide additional nutrients. You can use a fertilizer such as 2 cups of 16 percent sodium nitrate, 3 to 4 cups of 8-8-8 complete fertilizer or 1 cup of 33 percent ammonium nitrate. Use one of the suggested fertilizers, but not more than one.
Container-Grown Zucchini Fertilizer
Feed container-grown zucchini once a week with water-soluble fertilizer, as recommended by the Ohio State University Extension. A water-soluble fertilizer can be diluted and applied or hooked up to your garden hose. Use a fertilizer that has a NPK of 20-20-20 or 15-30-15. Avoid applying a fertilizer to your container-grown zucchini without watering it in. The salts found in the nitrogen will burn up the zucchini plant.