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How Ironite Plus Fertilizer Works

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Ironite Plus is a synthetic commercial fertilizer that includes micronutrients (such as zinc and iron), as well as macronutrients needed for plant growth (including nitrogen, phosphorus and potassium). It is a by-product of the smelting industry and is available in small or large quantities through nurseries and home garden centers.


Ironite Plus is available in several formulas and strengths, including granular and liquid types. All Ironite Plus formulas are soluble in water. The main ingredients are ammonium sulfate (a nitrogen-producing chemical that also adds acid to the soil) and muriate of potash (provides potassium). Ironite Plus may also contain urea, ammonium nitrate, water, fillers, iron, sulfur, boron and manganese.


Nitrogen, according to the manufacturer, produces lush growth, while phosphorus produces strong roots, colorful flowers and abundant fruits. Potassium helps plants "survive the rigors of harsh weather and drought." In alkaline soils, iron is bound up and unavailable for plants, resulting in chlorosis, or yellowing of the leaves. Ironite fertilizer may temporarily lower the pH level of alkaline soils, reducing the problem of chlorosis caused by iron deficiencies. Ironite fertilizers work because they contain ammonium sulfate, sulfur and potash, all highly acidic materials that lower soil pH, making iron more available. Also, Ironite Plus fertilizer adds iron to the soil in small amounts that are immediately available for plants.


Correcting very alkaline soils long term is difficult and expensive. Iron sulfate, the form of iron found in Ironite Plus, quickly binds in alkaline soils, making the product ineffective after the initial application. Chelated iron, while more expensive, doesn't bind in soil, making it a more effective long-term solution, according to Colorado State University Extension.


Overuse of fertilizers may actually contribute to iron chlorosis problems, according to KSL website. Human exposure to Ironite Plus fertilizers may cause acute symptoms, such as rash, eye irritation or gastric distress. The product may also stain hard surfaces or burn plant roots.


Synthetic fertilizers, such as Ironite Plus, provide additional nutrients to plants on a short-term basis, but don't improve the soil. Amend the soil with plenty of organic material, such as compost and well-rotted manure for a long-term improvement. Treating iron chlorosis is very difficult, long-term. Colorado State University recommends conducting a soil test through a professional lab or community extension service and then choosing plants that thrive in the native soil.

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