When to Fertilize Grass Seed?

Before Planting

• To prepare the ground for grass seed, you may want to consider fertilizing the soil between two and four weeks previous to seeding. This will prepare the soil for the seeds by making it rich with nutrients. Although you can fertilize during the planting process, doing it early instead can minimize the risk of the fertilizer burning the grass seedlings. If you fertilize the soil before planting, you do not need to add more fertilizer during the seeding process.

While Planting

• New grass should ideally be planted in the spring or fall, and fertilizer can be added during the seeding process. Simply add the fertilizer to the soil before sprinkling the grass seed. Use starter fertilizers, especially those meant specifically for grass seed, when planting new grass. Even if you don't, make sure that the fertilizer does not contain weed preventer, which can prevent the grass seed from germinating correctly. Grass fertilizer contains plenty of phosphorus, which enables the seedlings to establish strong root systems.

After Planting

• About a month (30 to 40 days) after seeding the ground, you should fertilize the soil once again. Once again, be careful to avoid any "weed and feed" fertilizers, most of which contain a herbicide that will prevent any grass seed still remaining from fertilizing. To be safe, you should wait until the grass is fully grown and has been mowed at least four times before using "weed and feed" fertilizers.

In General

• Even once the grass has been fully established, it is important to continue adding fertilizer. The normal schedule of adding fertilizer includes, at the very least, one dose of fertilizer during the spring (i.e., February to April) and another in the fall (i.e., August to October). You can also add another dose in the late summer, between June and August, if desired. At this point, you can use any fertilizer, including the "weed and feed" varieties.