It is possible to use a standard fertilizer spreader to distribute granular de-icing salt, but this introduces mechanical and chemical risks. A fertilizer spreader is designed for one type of material, and using it for rock salt or ice melt significantly alters the intended operating conditions. While this may provide a temporary solution, the long-term cost to the spreader often outweighs the convenience.
Spreader Types and Material Suitability
The feasibility of spreading salt depends heavily on the spreader’s design, which generally falls into two categories: drop and broadcast (rotary) spreaders. A drop spreader releases material directly beneath the hopper, covering only the width of the machine, making it ideal for precise application near sidewalks or driveways. The material flow gate is often narrow and can easily become clogged by the large, irregular size of rock salt granules, which are much coarser than standard fertilizer pellets.
A broadcast or rotary spreader uses a spinning disc to fling material in a wide arc, making it efficient for covering large, open areas like driveways or parking lots. This mechanism is generally more effective at handling the inconsistent size and weight of rock salt, but its wide distribution pattern sacrifices precision. The calibration settings established for fine, low-density fertilizer will not translate accurately to heavy, high-density rock salt, which can lead to over-application and material waste. Rock salt is often damp and abrasive, which can impede flow and lead to material bridging inside the hopper.
The Threat of Corrosion
The primary problem with using a fertilizer spreader for salt is the risk of corrosion to the equipment’s metal components. De-icing salts, particularly common rock salt (sodium chloride), are corrosive to untreated metals like steel, aluminum, and cast iron. When salt mixes with moisture, it creates a saline solution that accelerates the oxidation process, commonly known as rust. Many fertilizer spreaders use lighter-duty metal parts for their axles, gears, and shut-off plates that lack the protective coatings found on dedicated salt-spreading equipment.
This chemical attack begins almost immediately, targeting vulnerable components, such as the bearings and the gearing mechanisms that control the flow and spin rate. Corrosion in these areas can lead to mechanical failure, causing the gears to seize or the flow gate to stick, resulting in inaccurate application or complete equipment failure. Even plastic hoppers, which resist the salt itself, often rely on vulnerable metal frames, fasteners, and internal components that degrade quickly when exposed to chloride residue. Damage caused by a single use of salt without proper immediate cleaning can compromise the integrity and precision of the spreader permanently.
Essential Cleaning and Maintenance
To minimize corrosion risk if a fertilizer spreader is used for salt, immediate and thorough post-use cleaning is required. First, empty all remaining salt material from the hopper, as this hygroscopic residue draws moisture from the air, creating a corrosive brine. The entire spreader, including the hopper interior, axle, and spinning mechanism, must then be rinsed completely with fresh water to dissolve and wash away all chloride residue. Allowing the spinner to turn briefly during rinsing helps ensure water reaches the internal gear assembly.
After rinsing, drying the equipment is important, as residual moisture accelerates corrosion. The spreader should be dried with a cloth and then left to air dry completely, ideally in sunlight, before storage. Once dry, applying a protective layer, such as a silicone spray, water-displacing lubricant, or a light oil, to all exposed metal parts creates a barrier against moisture and salt particles. This step helps shield vulnerable areas like bearings, shafts, and flow gate mechanisms, extending the operational life of the spreader.