Applying granular fertilizer or seed to a lawn or garden requires a specialized tool known as a spreader. This device ensures the material is distributed evenly across the target area at a precise rate, promoting healthy growth and preventing chemical runoff. The choice of spreader depends on the area’s size, contour, and the required application precision, primarily between the drop spreader and the rotary (broadcast) spreader.
Understanding Drop Spreader Operation
The drop spreader is designed for high-precision application by allowing fertilizer to fall directly beneath the hopper. The mechanism involves a long, rectangular hopper with an adjustable opening at the bottom. Product is dispensed by gravity onto the ground only in the path directly between the spreader’s wheels as the machine is pushed forward.
This design gives the drop spreader its primary strength: accuracy and control. It is the ideal tool for applying product near hardscapes, flowerbeds, driveways, or water features, as it effectively eliminates overspray. The fixed width of the spread pattern ensures that valuable products like weed-and-feed or expensive seed are not wasted on unwanted areas.
However, the drop spreader operates slower than its counterpart because it covers only a narrow width with each pass. Achieving uniform coverage requires meticulous attention to overlapping the wheel marks from the previous pass to prevent visible missed strips, often called “striping.” If the overlap is not perfect, the resulting lawn can show alternating bands of dark green, over-fertilized turf and lighter, under-fertilized turf.
Understanding Rotary Spreader Operation
The rotary spreader, also known as a broadcast spreader, works by dispensing fertilizer onto a spinning impeller or plate. This mechanism throws the material outward in a broad arc, typically covering a swath between 4 to 12 feet wide. The main advantage is speed and efficiency, making it the preferred choice for covering large, open areas quickly. The wide distribution pattern significantly reduces the number of passes required to cover a lawn, making it efficient for general applications over large properties.
A major drawback is the inherent lack of precision and the potential for uneven distribution. The spin mechanism often results in a lighter application rate in the center of the swath, with heavier application toward the edges of the throw pattern. Moreover, the material is cast in all directions, making it difficult to control the boundaries and potentially throwing granules onto non-target areas like sidewalks or water bodies.
Selecting the Right Spreader for Your Area and Fertilizer
The choice between a drop and a rotary spreader is determined by a synthesis of three factors: area size, the product’s physical properties, and the required precision. For large, open areas, the rotary spreader’s ability to cover significant ground with its wide swath makes it the clear recommendation. In contrast, properties that are small, intricately shaped, or have many obstacles benefit from the drop spreader’s confined application width and precise control.
The physical properties of the fertilizer or seed also influence the spreader’s effectiveness. Rotary spreaders perform optimally with dense, uniform, and spherical pellets, as these characteristics allow the granules to be thrown farther and more predictably. Conversely, finely powdered materials or lightweight seeds can clog the openings of a drop spreader or be poorly distributed by a rotary spreader due to wind resistance and the lack of ballistic consistency.
Precision requirements should be the deciding factor when applying specialized products. If you are applying a highly concentrated material, such as a weed killer or a grub control product, near a sensitive area like a vegetable garden or a stream, the drop spreader is the safer option. The fixed-width application minimizes the risk of chemical drift or overspray, which can damage non-target plants or pollute water sources. For general, low-concentration fertilizer applications across a large, uniform lawn, the speed advantage of the rotary spreader often outweighs the minor loss in precision.
Maximizing Results Through Proper Application
Once a spreader is chosen, achieving a uniform application rate relies on proper setup and technique, regardless of the model. The most important initial step is calibration, which involves matching the product manufacturer’s recommended application rate to the spreader’s mechanical setting. Since walking speed and the material’s physical properties influence the flow, it is advised to perform a small calibration test on a hard surface to verify the output rate before treating the entire area.
A highly effective technique for ensuring even coverage is the half-rate, criss-cross application pattern. Instead of applying the full recommended rate in a single pass, the operator should set the spreader to half the rate and make two passes over the area. The second pass should be perpendicular to the first, creating a grid pattern that minimizes the chance of missed strips or localized over-application.
Consistency is also paramount, which means maintaining a constant walking speed, as any change will directly affect the amount of product dispensed per square foot. Finally, proper maintenance immediately after use is necessary for the spreader’s longevity and accuracy. Fertilizer salts are corrosive, so the hopper and the mechanism must be thoroughly cleaned and dried after each use to prevent rust and ensure the moving parts remain free of obstruction.