Most fertilizers have NPK amounts printed on their labels. NPK stands for the nitrogen, phosphorous and potassium amounts in the fertilizer. If you use a fertilizer with 10-10-10 NPK, the bag contributes 10 percent of each nutrient to your yard. To calculate how much 10-10-10 nutrients are in a 50 pound bag, multiply 50 by 0.10. You results will indicate that there are 5 pounds of each nutrient and the rest may be sand or limestone. Application of 10-10-10 depends on if you use liquid or granulated fertilizer.
Things You'll Need
Fertilizer drop spreader, if needed
Decide if you want to use quick release or slow release fertilizer. The majority of quick release fertilizers come in a liquid form that supplies plants nutrients quickly but must be applied every two to three weeks. Slow release fertilizers come in a granulated form that slowly provides nutrients and should be applied ever six to eight weeks.
Water your lawn every day for three days before applying fertilizer. The nitrogen in fertilizer can burn dry lawns.
Attach the bottle of liquid fertilizer to your garden hose. Walk back and forth in imaginary lines across your lawn. Spray from side to side, so that you get an even application. Reapply the fertilizer according to the directions in a couple of weeks. Water as directed
Pour your granulated slow release fertilizer in a fertilizer drop spreader. Calibrate your fertilizer drop spreader to drop 10 pounds of fertilizer every 1,000 square feet. Walk slowly across your lawn, so that the fertilizer spreads evenly. You can hand spread areas that you miss. Water as directed.
Set your garden hose to a medium spray to avoid blowing away your fertilizer. Give your lawn lots of water to avoid dehydration. You can slowly irrigate trees, so the fertilizer drains deeply in the soil and gets to their roots. Reapply in six to eight weeks according to the product directions.
If you start to see brown spots on your lawn, you may be over-fertilizing. Always use the amount indicated on the label.
Avoid fertilizing your lawn with a fertilizer that contains nitrogen before it has a chance to come out of winter dormancy, because you will encourage the growth of weeds.