Nitrogen is provided by any lawn fertilizer, since all general-purpose lawn fertilizer formulations include that important nutrient since it's the nutrient used by plants in the greatest quantity. Professional soil testing labs generally do not test for nitrogen because levels in the soil naturally fluctuate too much for one measurement to be very useful, but it's usually safe to assume that a nitrogen boost by way of fertilization is needed when planting new turf (or when fertilizing established turf during its growing season).

Lawn fertilizer applications are regulated by Maryland law to avoid the over-application of nutrients that can pollute runoff and harm the Chesapeake Bay and other waterways. Our Lawn Fertilizer Table lists the specifics for application rates (based on nitrogen dosage) and for application timing based on lawn type (tall fescue, zoysia, etc.).

While organic matter like compost or good-quality topsoil can provide some nutrients (including nitrogen), it may not be enough by itself (especially when you're starting new grass from seed) to get the plants established. In part, this is because such nitrogen sources rely on soil microbes to turn it into a form absorbable by roots, and that process can't support optimum grass germination and establishment by itself. If you're instead adding topsoil or compost to the existing soil for the purposes of improving drainage or compaction, or for leveling-out low spots, then that amendment should be tilled in so that it is evenly mixed into the top few inches of soil. (Most home-use/rentable tillers will only incorporate materials about 4 to 6 inches deep, but that is fine for establishing lawns.)

The order should be:

1. Prepare the soil: level as needed and till-in amendments like compost or topsoil.
2. Sow seed; fertilizer can also be applied just before or after this step, it's not critical. (If you bury a fertilizer application too much and separate that layer from where the seed is sprouting, those nutrients will initially be out of reach of those young roots. In established lawns that are fertilized and overseeded, a fertilizer application would lie alongside the seed on the soil surface, so they'd share the same "layer" without problems.)
3. Cover the seed with either a fine layer (no greater than a quarter-inch to half-inch) of compost/topsoil, or with a light layer of straw (one or the other, not both). This mainly just helps to keep the seed from drying out too quickly and hiding it from hungry birds. Straw might also reduce the risk of soil erosion until the seedlings root in more fully.

Miri

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