Organic Fertilizer for Potatoes

Nutrient and Soil Requirements of Potatoes

• The National Sustainable Agriculture Information Service notes developing potatoes need high levels of nitrogen and potassium. As a guideline, Utah State University Cooperative Extension recommends 4 to 6 pounds of nitrogen per 1,000 square feet, added two or more times during the growing season. Acceptable soil pH can vary, but a level between 5.0 and 5.2 is recommended to prevent potato scab.

Organic Options

• Organic nitrogen is commonly supplied to potatoes as fertilizer in compost and dairy and poultry manures. For growing potatoes, Steve Solomon, writing in the June/July 2006 "Mother Earth News" suggests making an organic fertilizer of seed meal, agricultural lime, gypsum, dolomitic lime, bone meal, rock phosphate, guano and kelp meal and using steer manure or finished compost. Sulfur is a good organic option to lower soil pH.

Warnings

• If overapplied, organic matter can burn and damage young plants because it contains high levels of salts. Follow all fertilizer instructions carefully. Watch for signs of nitrogen imbalance in growing potatoes. Nitrogen-deficient potatoes are stunted and older leaves turn yellow; too much nitrogen delays tuber development and causes thick vine growth.