Lawn fertilization is a regular maintenance practice that supplies the necessary nutrients to encourage dense, vibrant turf growth. A healthy, well-fed lawn actively defends itself against weeds and disease, improving its appearance and resilience. Successfully distributing the product requires a methodical approach that begins long before the granules hit the grass. Following a precise application technique ensures the nutrients are delivered evenly and safely across the entire area.
Selecting the Right Fertilizer and Timing
The selection of fertilizer should be guided by your grass species and the season to align with the plant’s active growth cycle. Cool-season grasses like fescue and bluegrass grow most vigorously in the cooler temperatures of spring and fall, making these periods ideal for nutrient application. Warm-season grasses, such as Bermuda and Zoysia, thrive in the heat of summer and should receive their primary feeding during the late spring and summer months. Applying nitrogen too late in the fall can stimulate tender new growth that may be damaged by frost as the grass attempts to enter dormancy.
Fertilizer products are labeled with an NPK ratio, a sequence of three numbers representing the percentage by weight of Nitrogen (N), Phosphorus (P), and Potassium (K). Nitrogen primarily promotes green, leafy growth, while Phosphorus supports root development and Potassium enhances overall plant health and stress tolerance. Granular fertilizers are the most common choice, offering a slow-release feed that provides sustained nutrition over several weeks. Liquid fertilizers deliver nutrients almost immediately, useful for correcting a sudden deficiency, though they require more frequent reapplication.
Spreader Types and Calibration
Two primary spreader types are available for granular products, each suited to different lawn characteristics. The rotary, or broadcast, spreader uses a spinning disk to throw granules in a wide arc, making it the fastest option for covering large, open areas. Since the pattern tapers toward the edges, this type requires careful overlapping to prevent uneven distribution that results in noticeable stripes.
The drop spreader precisely deposits granules directly beneath the hopper, making it more accurate for treating small lawns or areas bordered by flower beds or sidewalks. Its precision requires more passes to cover the same area, and the wheels must slightly overlap the previous track to ensure complete coverage.
The spreader must be properly calibrated to deliver the specific rate recommended on the fertilizer bag. Fertilizer labels provide a starting setting, but this number is often inconsistent due to variations in walking speed, product density, and spreader model mechanics. Improper calibration is the primary cause of lawn damage; under-application wastes product while over-application concentrates salts that can burn the grass blades. A simple calibration test confirms the necessary setting for your specific application rate and walking pace.
Step-by-Step Application Technique
Preparation for fertilization begins with mowing the lawn one to two days before the application. Mowing to the typical height of three to three-and-a-half inches ensures that the fertilizer granules can fall directly to the soil surface rather than resting on long grass blades. Allowing 24 to 48 hours for the grass to recover from the stress of cutting also helps improve the plant’s ability to absorb the nutrients.
Always load the spreader on a hard surface, such as a driveway or patio, to manage any spills that occur during the process. Granules that spill directly onto the lawn create an immediate concentration of salts, leading to a distinct, dark green or scorched burn spot.
Before beginning the main application, create a header strip by making one or two passes around the entire perimeter of the lawn. This border establishes a buffer zone and provides a safe area for turning and maneuvering the spreader.
When treating the main area, push the spreader back and forth in straight, parallel lines, working inward from the header strip. Maintaining a consistent walking speed is important, especially with a rotary spreader, to ensure an even throw pattern.
The most crucial step is shutting off the flow gate immediately upon reaching the header strip or perimeter and before making any turn. Failure to close the gate while stopping or turning causes a pile-up of product at the turning point, creating a circular burn mark.
For a rotary spreader, align the edge of the current pass so the fertilizer stream hits the wheel track from the previous pass, achieving the necessary 50% overlap for uniform coverage. A drop spreader requires aligning the wheel of the current pass just outside the wheel mark of the previous pass to avoid leaving untreated gaps. After finishing the application, any granules that have landed on sidewalks, driveways, or patios must be swept back onto the lawn or collected.
Immediate Post-Fertilization Care
The most important step following the application of granular fertilizer is immediate watering. Granules contain concentrated salts that, if left on the grass blades, will draw moisture out of the plant tissue, resulting in visible scorching known as fertilizer burn. Watering is necessary to dissolve the particles and move the nutrients down into the soil where the roots can absorb them.
A light, thorough watering of about one-quarter inch is generally sufficient, which often corresponds to 15 to 30 minutes of irrigation, depending on the sprinkler system. This activates the fertilizer without causing excess runoff that could wash the product away. Cleanup of hard surfaces is also immediately required, as the iron content in many fertilizers can create stubborn rust-like stains if the granules become wet.