Answer: In general, lawns can be fed in April, just as new growth begins, in June, in September and again in late November. The University of Nebraska suggests a June and a September feeding. June, to get it through the summer and September or early October to strengthen the roots so it will be ready to grow in the springtime. In June use a 3-1-2 ratio of nitrogen, phosphorous and potassium (NPK). Look for fertilizers with a 21-7-14 or similar formula. In the fall, use a product with a low nitrogen content, but a high phosphorous and potassium content such as a 10-20-20 or similar formula. Here's a list of lawn care publications from the university that you might find helpful: http://lancaster.unl.edu/hort/lawncare.shtml
Best wishes with your turf!
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