When addressing magnesium deficiencies in soil, growers have several options for magnesium fertilizers. Among the most common are Magnesium Oxide (MgO), Dolomitic Lime, and Magnesium Sulfate (Epsom Salts). Each offers distinct benefits and drawbacks, making the choice dependent on specific soil conditions, crop needs, and application methods. Understanding these differences is key to optimizing nutrient uptake and maximizing crop yields.

Magnesium Oxide (MgO) is a concentrated source of magnesium, typically offering a high percentage of elemental magnesium (often 50-60%). It is a slow-release nutrient, meaning it becomes available to plants gradually over time as it reacts with soil moisture and acids. This characteristic makes MgO a long-lasting soil amendment, particularly effective in neutral to slightly acidic soils. Its primary advantage lies in its high magnesium content per unit weight, which can make it cost-effective for large-scale applications, especially when considering price per unit of magnesium. However, MgO's solubility can be slower, meaning its effects might not be as immediate as more soluble forms.

Dolomitic lime, a natural mineral, contains both magnesium and calcium. It's often used not only to supply magnesium but also to raise soil pH. If a soil test indicates both a need for magnesium and a low pH, dolomitic lime can be an economical choice as it serves a dual purpose. However, if the soil pH is already neutral or alkaline, applying dolomitic lime could lead to over-liming, which can hinder the availability of other essential nutrients. Pelleted dolomitic lime offers easier application but is typically more expensive. Magnesium sulfate, on the other hand, is a highly water-soluble form of magnesium, making it rapidly available to plants. It's often used for quick correction of magnesium deficiency, particularly in crops sensitive to low magnesium levels or when a fast-acting foliar spray is desired. However, its rapid solubility can also mean it leaches out of the soil more quickly. When considering which magnesium fertilizer to buy, it's important to consult soil test results and consider the specific needs of your crops and soil conditions to make the most informed decision.