Water and fertilizer go together in many ways. They are both needed by turf and other landscape plants.  They can also be used correctly to achieve positive results and incorrectly to cause pollution or waste precious resources.  In order to minimize the latter, a simple set of questions should be asked before using fertilizer.

1. What is the % of nitrogen, phosphorous and potassium? This is easily seen on the front of the bag as a ratio such as 22-3-8; in this case, 22 indicates the nitrogen percentage, 3 indicates the phosphorous percentage and 8 lists the potassium percentage.  Most Nebraska lawns do not have a need for phosphorous or potassium applications except in rare circumstances, so focusing on the nitrogen is most important.

2. What is the type(s) of nitrogen in the bag? It’s common for both slow (urea formaldehyde, sulfur coated urea, methylene urea, IBDU) and fast (ammonium nitrate, ammonium sulfate, urea) release forms to be combined in a bag of lawn fertilizer.  In order to apply nutrients optimally, a 50/50 mix should be used at most times of the year, with the exception of mid-fall, when only a very light rate of fast release nitrogen should be applied. 

3. Are there any other active ingredients? In some cases, various micronutrients and certain pest control agents are included with the fertilizer.  It’s important to read the label thoroughly to know which ones are present and what the effects of using them will be.

4. What is the weight of the bag?  This is important because it’s rare that a whole bag will be needed; more likely some portion of a bag such as 3/4ths of a bag, 2 bags, 1 1/3^rd bag, etc. should be applied.

5. How many square feet does this product cover? This will also help with the amount of product to be applied; products can cover anywhere between 1,000 and 15,000 square feet.

6. Which weeds/insects/fungi are controlled with this product?  In some cases, the product contains only fertilizer, however, many also contain weed, insect or fungi control agents.  If you’re not trying to prevent or control a pest, it’s best to apply products containing only nutrients.

7. What is the recommended spreader setting? It’s very important to match up the recommended setting with the brand of fertilizer spreader being used.  If this information is not present, there is no need to worry, the amount of product to apply can be easily calculated – simply divide the amount of nitrogen per 1,000 sq. ft. desired by the percentage indicated.  That will provide the amount of product to apply to every 1,000 sq. ft.  Next, simply multiply that amount by the number of 1,000 sq. ft. units in the lawn for the total amount to apply.  For example, 0.75 lb N rate / 0.22 % = 3.4 pounds of product per 1,000 sq. ft or about 3 ½ pounds.  Then, if the lawn is 5,000 sq. ft., 3.4 x 5 = 17.04 pounds of product to apply on that lawn.

8. What are the risks or potential environmental hazard associated with this product?  How would the user minimize them? In most cases, possible risks related to the use of lawn fertilizer are movement of the nutrients off of the lawn, where they can contaminate lakes, streams and ponds.  Applying the product evenly, watering it off the turf blades and blowing stray granules that have fallen on the sidewalk or street back to the lawn will greatly reduce environmental issues.

9. How, when and where to apply this product? Even though the print is usually small, very helpful information about timing and application location will be indicated on the bag and should be followed closely to enhance product performance and limit environmental contamination.  Splitting the amount to be applied in half, and applying the first half in a north-south and the second in an east-west direction will increase the uniformity of and effectiveness of the application.

10. What are the first aid instructions for this product? Again, usually in small font, most fertilizer bags contain first aid instructions.  On many product labels, this information is bordered by a red box.  Follow these instructions explicitly.