Answer: Fertilizers contain three primary nutrients
Labels show the ratios of N-P-K (in order) included in the bag of fertilizer. Since phosphorus is the most important nutrient for root development, it is the highest number in a bag of a starter fertilizer. Once the roots are established, nitrogen becomes the most important nutrient for the growth of the aboveground parts.
Once your lawn is established, deep infrequent watering will encourage deep rooting. Apply one inch of water per week in one application in mild weather or two applications during hot weather. The best way to figure out how much water your sprinkler is putting out, place several empty tuna or cat food cans on the lawn and water as you normally would, making note of how long your sprinkler runs. Check the amount of water collected in the cans. Your goal is one inch. Once you figure out how long you need to run the sprinkler to apply an inch of water, you'll know how long to keep your sprinkler on. You can divide the time into the number of days you water. For instance if it takes 30 minutes for your sprinkler to apply an inch of water you can run the sprinkler for 15 minutes every 3-4 days to provide one inch of water to your lawn each week during the summer.
As for feeding, use a 3-1-2 ratio of NPK in April, June, September and mid-November and you'll have a thick, lush lawn.
Best wishes with your lawn!
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