Question: I often see the words “use a well-balanced fertilizer” for the lawn at this time of year. I am not sure what that means.

Answer: It all has to do with the numbers on the bag, which stand for the percentage of nitrogen, phosphorous, and potassium in the bag. The numbers 12-12-12 or 10-10-10 are common “balanced” dry fertilizers sold at garden centers. If you add up the numbers, you realize that the numbers add up to less than 100%, meaning that many bags of dry fertilizer contain considerable filler ingredients that make it easier to spread the fertilizer evenly on the lawn. Some fertilizer companies claim to have better filler ingredients that enhance how the fertilizer is distributed and released into the lawn.

Some companies sell spreaders which have settings to distribute their brand of fertilizer on the lawn at their recommended rates so homeowner don’t have to try and figure it out themselves.

Here are my calculations to figure out how much dry fertilizer to apply to the lawn at university-recommended rates which are best for the lawn. This requires folks to measure the rough square footage of their lawn by measuring the area of the lawn (even rough measurements are fine) they have.

If you have a 50-pound bag of 10-10-10 fertilizer, then multiply the first number on the bag by five and add two zeros. So 10 x 5 = 50. Add two zeros = 5,000, which is the amount of lawn the bag will cover at the correct rate. Since the average size of a lawn in Allen County is about 10,000 square feet, it would take two 50-pound bags of 10-10-10 fertilizer to apply to the lawn at the correct rate. If the bag of fertilizer is only 35 pounds, then multiply the first number by 3.5.

If one only has a lawn that is about 2,500 square feet, it will only take a half of a 50-pound bag of 10-10-10 to adequately fertilize the lawn.

Use a lawn spreader and spread over the lawn in two directions so the fertilizer is applied evenly. Use a whirlybird hand held spreader to apply the fertilizer as evenly as possible to smaller lawns.

Fertilizer is in short supply and more expensive because of supply issues related in part to the war in the Ukraine. This might be a time to seek out a company that applies organic controls such as compost to lawns. I see many houses in the city of Fort Wayne with very small areas of turf in the front yard. If your lawn is small, apply compost, worm castings, or Canadian sphagnum peat moss to the lawn. Just lightly rake the material into the lawn. Make sure you can still see the grass after applying. You will be surprised on how well the lawn will look after using these materials. It is important to try to keep a lawn healthy by applying some fertilizer to the lawn. This year make sure to apply correct rates and consider using organic materials for smaller lawns.

The Plant Medic, written by Ricky Kemery, appears every other week. Kemery retired as the extension educator for horticulture at the Allen County Purdue Extension Service. To send him a question, email trich@jg.net.