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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteFertilizer is made by turning nutrient-bearing raw materials into compounds and then selling those compounds alone or combining them into a finished product. There is no single fertilizer recipe or factory sequence: nitrogen products commonly start with ammonia, phosphate products can start with mined phosphate rock, and potassium salts may be combined with either. The ingredients may react chemically to form new compounds, be physically blended without reacting, or be mixed into a liquid.
Those differences matter because two products that supply similar nutrients may have been made by different routes. The feedstocks, intermediate materials, finishing steps, and byproducts depend on the particular fertilizer and the plant that makes it.
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What fertilizer manufacturers are making
Most fertilizer products are designed around nitrogen (N), phosphorus (P), and potassium (K), the three primary nutrients used to describe many fertilizers. Manufacturers do not usually turn raw materials directly into one universal finished product. Instead, they make nutrient compounds or intermediates, then sell them as individual products or combine them into multi-nutrient fertilizers.
A product containing just one nutrient source is often called a straight fertilizer. A mixed fertilizer contains at least two primary nutrients. The word “mixed” does not by itself tell you how it was manufactured: ingredients may have been chemically reacted together, physically blended as already-made materials, or combined in a liquid. EPA process descriptions distinguish these routes.
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- WHERE TO USE: For use with vegetable, fruit, and tomato plants, whether in-ground or indoor or outdoor container plants
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The manufacturing chain therefore has two broad parts: producing nutrient materials and formulating them into a saleable product. Some plants carry out several stages; other products or intermediates may be made elsewhere before they reach the facility that performs the final formulation.
How nitrogen fertilizer is made
Start with nitrogen in the air and a source of hydrogen
EPA identifies atmospheric nitrogen and hydrogen as the basic inputs for ammonia manufacture. Nitrogen is abundant in air, but it must be converted into a form that can be used in fertilizer. The hydrogen used in the EPA-described process is derived from natural gas or petroleum-refinery byproducts. That does not mean every plant uses the same hydrogen source or that every downstream fertilizer is produced at the same site.
Make ammonia as a central intermediate
The inputs are brought together to manufacture ammonia. Ammonia is both a nitrogen fertilizer in its own right and an important intermediate for other nitrogen products. In the production chain described by EPA, it is used in making urea, ammonium nitrate, and nitric acid products. This makes ammonia a useful point of reference for understanding how raw feedstocks can lead to several different finished fertilizers.
After ammonia is made, the manufacturing route depends on the desired product. A facility may use ammonia directly as a fertilizer, or it may send or use it as an input in a process that makes another nitrogen compound. The chain is not necessarily a single continuous operation in one plant: raw-material sourcing, ammonia manufacture, and downstream product manufacture can be separate stages.
What the nitrogen route does—and does not—tell you
The feedstock chain explains where the nitrogen intermediate comes from, but it does not establish a universal plant design, product formulation, or manufacturing cost. Nor does the fact that two products contain nitrogen mean they were made in the same way. Their final form and route depend on the compound being produced and the facility’s process.
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How phosphate fertilizer is made
From mined phosphate rock to phosphoric acid
Many phosphate fertilizer routes begin with phosphate rock. EPA describes phosphate manufacturing as including sulfuric acid production from elemental sulfur and wet-process phosphoric acid production from phosphate rock. In the wet process, sulfuric acid reacts with the rock, producing a slurry that includes phosphoric acid and calcium sulfate. The calcium sulfate byproduct is commonly called phosphogypsum.
Phosphoric acid is an intermediate used to make phosphate fertilizer products. The resulting slurry is not itself the end of every production route: the acid can be used in later reactions or formulation steps. Phosphate rock and sulfuric acid are therefore upstream inputs, while phosphoric acid is a material that connects the raw-material stage to downstream fertilizer manufacture.
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EPA’s phosphate standards page describes diammonium phosphate (DAP) manufacture as a reaction between phosphoric acid and ammonia. Triple superphosphate (TSP) is described as being made by reacting phosphate rock with phosphoric acid. These examples show why “phosphate fertilizer” is not one recipe: different products use different inputs and reactions, even when they belong to the same nutrient family.
For ammonium phosphates, EPA also describes phosphoric acid and ammonia reacting to form a slurry that is then converted into solid granules. The EPA process assessment describes drying, cooling, screening, and shipment after granulation. These are process descriptions, not a guarantee that every contemporary facility uses identical equipment or an identical sequence.
The phosphate byproduct
Phosphogypsum is a material created during wet-process phosphoric acid production. EPA identifies it among wastes associated with fertilizer production. Its presence is a consequence of the phosphate-rock and sulfuric-acid route, not a nutrient or ingredient that should be assumed to appear in every fertilizer product. Whether and how a particular facility handles production wastes depends on its process and applicable requirements.
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Where potassium fits
Potassium fertilizer salts, commonly described as potash, can be used alongside nitrogen and phosphate inputs in mixed fertilizers. In the process descriptions covered here, potassium salts are inputs to some mixed-product routes; they are not a step in the ammonia or wet-process phosphoric-acid chains.
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That distinction helps explain the “NPK” label. It identifies a product that supplies multiple primary nutrients, but it does not reveal a single manufacturing method. A mixed nutrient product may be made by chemical reaction and granulation, by physically mixing dry fertilizer ingredients, or by mixing materials in liquid form. A label describing nutrient content does not, on its own, identify which of those routes was used.
How manufacturers turn ingredients into finished products
Chemical reaction and ammoniation-granulation
In ammoniation-granulation, liquid and dry raw materials can be brought together in a granulator. EPA’s historical process description lists ammonia, phosphoric acid, phosphate compounds, sulfuric acid, and potash among possible inputs. Depending on the product, a reaction occurs as materials are processed, and the reacting material helps form granules.
The granulator is only one part of the route. The resulting material is sized: screens separate particles, fines can be recycled, and oversized particles can be crushed or returned to the process. Correctly sized product may be dried when needed, then cooled and moved to storage. The exact equipment, operating conditions, and sequence vary with the product and the facility.
This route is different from simply putting finished ingredients together. Since ingredients react during manufacture, the granulated product is produced through a chemical process as well as through physical handling and sizing.
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Physical blending of dry ingredients
Mechanical bulk blending combines dry fertilizer ingredients into a granular mixed product without a chemical reaction. The ingredients have already been manufactured; blending brings them together in the desired formulation. The physical mixture can be a multi-nutrient product even though the components have not chemically become a new compound during blending.
For a buyer, the practical point is that a mixed product may contain ingredients combined by blending rather than reaction. The word “mixed” alone does not distinguish those manufacturing routes. The nutrient analysis describes the nutrients supplied, while manufacturing method is a separate question.
Liquid mixing
Liquid fertilizer mixing also has more than one route. EPA’s assessment distinguishes “hot mix” products, in which materials chemically react, from “cold mix” products, in which materials are physically mixed. As with granules, a liquid product’s appearance does not tell you by itself whether a chemical reaction occurred during manufacture.
How the main manufacturing routes differ
| Route or product stage | Key inputs or intermediate | What happens | Product or process detail |
|---|---|---|---|
| Ammonia manufacture | Atmospheric nitrogen and hydrogen | Inputs are used to manufacture ammonia | Hydrogen is derived from natural gas or petroleum-refinery byproducts in EPA’s description |
| Wet-process phosphoric acid | Phosphate rock and sulfuric acid | Sulfuric acid reacts with phosphate rock to form a slurry | The slurry includes phosphoric acid and calcium sulfate, commonly called phosphogypsum |
| DAP manufacture | Phosphoric acid and ammonia | The inputs react to make DAP | EPA describes ammonium phosphate production followed by conversion to solid granules |
| TSP manufacture | Phosphate rock and phosphoric acid | The inputs react to make TSP | EPA identifies this as a phosphate fertilizer manufacturing route |
| Dry bulk blending | Already-manufactured dry fertilizer ingredients | Ingredients are physically mixed without a chemical reaction | The result can be a granular mixed fertilizer |
| Liquid mixing | Liquid fertilizer materials | Materials may react in a hot mix or be physically mixed in a cold mix | EPA distinguishes both forms of liquid mixing |
The table describes routes, not a universal ranking. EPA’s process descriptions do not establish that one route is always cheaper, more efficient, or environmentally preferable than another. Those conclusions would require evidence about specific facilities, products, and operating conditions.
How granules are finished and prepared for shipment
Once a granular product has formed, finishing steps help separate particles by size and prepare the saleable material for handling. EPA’s process descriptions support a sequence that can include screening, recycling fines, crushing or recycling oversize particles, drying when needed, cooling, and storage before shipment. Not every product requires every step, and the exact arrangement is facility- and product-dependent.
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- Form or collect the material. A reaction route can create granules in a granulator; other routes may start with manufactured granular ingredients.
- Screen for size. Screens divide material into size fractions. Fines may be returned to the process, while oversized particles may be crushed or recycled.
- Dry when needed. Drying is part of some described finishing routes, rather than a universal requirement for every fertilizer.
- Cool and store. EPA process assessments describe cooling and storage before shipment for relevant granular products.
- Ship the finished product. The product leaves the manufacturing or finishing operation for distribution to its next destination.
These steps describe physical handling and product sizing; they should not be confused with nutrient chemistry. Screening does not create a nutrient, and blending does not necessarily involve a reaction. Conversely, a reaction-based route can both form fertilizer compounds and create material that is subsequently sized and finished.
Emissions rules and production wastes
Fertilizer manufacturing also has environmental and regulatory dimensions. EPA’s phosphate fertilizer regulatory page lists standards for several source categories and emissions limits, including fluoride limits for specified processes. Those limits are regulatory requirements associated with covered processes; they are not a description of the nutrient content or general quality of the fertilizer in a bag or bulk shipment.
The regulatory page was last updated June 24, 2026. The applicable rule and a facility’s circumstances determine the relevant compliance details, so a general process explanation cannot establish what controls or limits apply at every site. Separately, EPA identifies phosphogypsum among fertilizer-production wastes associated with phosphoric acid production.
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What the manufacturing route means for a finished fertilizer
Knowing how a fertilizer is made helps distinguish several facts that product names can blur together:
- Feedstock: Nitrogen manufacture can begin with air and a hydrogen source; phosphate production can begin with phosphate rock and sulfuric acid; potassium salts can enter mixed-product formulations.
- Intermediate: Ammonia is central to the described nitrogen chain, while phosphoric acid connects phosphate-rock processing to products such as DAP.
- Reaction or blending: Some formulations chemically react ingredients; dry bulk blending physically combines manufactured ingredients without a reaction.
- Finished form: Relevant routes produce granular solids or liquid products, with finishing operations varying by product.
- Byproduct and regulation: Wet-process phosphoric acid production creates calcium sulfate, commonly called phosphogypsum, and specified processes are subject to EPA emissions standards.
These details explain manufacturing, not how a particular fertilizer should be selected or applied. The production route alone does not establish a suitable nutrient ratio, crop use, or application rate; those choices depend on the intended use and the product’s formulation.
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