Should I Fertilize New Sod for the Fall?

Fertilizing at the Time of Planting

• Starter fertilizer must be spread at the time of planting to promote healthy sod root growth. Spread a starter fertilizer that has a high percentage of phosphorous. You can use 20 pounds of a starter fertilizer that has a NPK amount of 5-10-5 or 5-2-10 per 1,000 square feet as recommended by the University of California. Work the fertilizer into the first 2 to 4 inches of top soil. Water the bare area and sod the lawn.

Second Fertilizing

• Apply a second fertilizer four to six weeks after it has been installed, as recommended by the University of Rhode Island. Use a fertilizer that has a higher percentage of nitrogen than the one you used at the time of sod installation. Fertilizers that have a NPK amount of 4-1-3 or 2-1-1 will add enough nutrients for growth without stressing out the new sod. Spread at a rate that distributes 1 lb. of nitrogen per 1,000 square feet.

Fall Fertilizing

• Fall fertilizing must be conducted while the grass has stopped growing and before the ground freezes, according to Pennsylvania State University. Typically, this occurs in the early fall for warm season grass types or in the late fall for cool season grass varieties. Gardeners can generally fertilize before the winter sometime around Thanksgiving, according to Pennsylvania State University. Use 1 to 1 1/2 lbs. of slow release nitrogen per 1,000 square feet to fertilize.

Other Considerations

• Avoid fertilizing late in the season or when grass is still growing. Late fall fertilizing when the grass is still growing raises the risk of your lawn contracting a fungal disease such as pink snow mold or gray snow mold, according to Pennsylvania State University. In addition, giving your sod fertilizer when it is still growing encourages new growth that can be damaged in the winter from frosts and ground freezes. Moreover, refrain from spreading more than 1 1/2 lbs. of nitrogen when fertilizing in the fall to prevent new growth.