It’s time to fertilize your lawn one last time. Congratulations if you fertilized your lawn in September and again in November. If you’ve been putting off your November fertilization, now is the time to do it.
Make sure to remove the leaves or mow to mulch them and let them settle down into the grass. Then apply 0.75 pounds actual Nitrogen for 1000 square feet. You should be using fertilizer containing mostly slow release nitrogen. Often this percentage is listed on the fertilizer bag. The active ingredients may list sulfur coated urea (SCU), polymer coated urea, or methylene ureas. Fertilizer made of organic material also contains slow release nitrogen.
The “0.75 pounds actual Nitrogen per 1,000 square feet” instruction is often confusing. To apply lawn fertilizer correctly, you need to know two things – the area of your lawn and the analysis of your fertilizer. Measuring your lawn lets you determine how much fertilizer you should apply. For example, if my lawn is 5,000 square feet, I will need to apply 5 x 0.75 or 3.75 pounds actually nitrogen.
Since the fertilizer isn’t 100% nitrogen, you’ll need to apply more weight of fertilizer than just the 3.75 pounds. If the analysis on the fertilizer bag is 24-4-8, the fertilizer contains 24% nitrogen or 0.24 pound actual nitrogen for each pound of fertilizer. In this example, 10 pounds of fertilizer would give you 2.4 pounds of actual nitrogen. That’s still not the 3.75 pounds we need, so we can do a simple calculation to determine how much weight of fertilizer to apply. Just divide the amount of actual nitrogen you need by the amount of actual nitrogen in a pound of fertilizer. In this example we divide 3.75 by 0.24 and find we need 15.6 pounds of fertilizer for our 5,000 square foot lawn.
There’s a great article about fertilizing your lawn at http://www.agry.purdue.edu/turf/pubs/ay-22.pdf.
