“NPK fertiliser” covers an enormous range — we stock 130 analyses — so the real question is never who sells NPK. It is which analysis fits your paddock, and how to compare two quotes that look similar and are not.
Compound, blended or high tower
Three ways to get N, P and K into one product, and they are not interchangeable.
| Type | How it is made | Where it fits |
|---|---|---|
| Compound | Every granule contains all three nutrients | No segregation in transit or the spreader — each granule delivers the full analysis |
| High tower | Sprayed from a melt down a tower; hard, near-spherical granules | Wide spreading, long cartage, storage — see the explainer |
| Blended | Separate straight fertilisers mixed together | Any analysis you like, including one matched to your soil test — but granules must be size-matched or they segregate |
The trade-off in full: compound vs blended.
Compare on nutrient units, not price per tonne
This is the single most useful habit in buying fertiliser. Add the three numbers in the analysis — that is your total nutrient units per tonne.
| Analysis | N + P + K units | Nutrient in 25 MT |
|---|---|---|
| 15-15-15 | 45 | 11.25 t of nutrient |
| 16-16-16 | 48 | 12.0 t |
| 17-17-17 | 51 | 12.75 t |
| 20-10-10 | 40 | 10.0 t |
| 25-5-5 | 35 | 8.75 t |
A 17-17-17 carries almost half as much nutrient again as a 25-5-5. If both were priced the same per tonne, one is clearly the better buy — and that is before asking whether the ratio suits your soil. Our catalogue lists total units for all 130 analyses so you can run this before anyone quotes you.
Choosing the ratio
Match the ratio to the deficit, not to habit. A balanced grade on ground that is only short of nitrogen means paying to apply phosphorus and potassium you did not need — on every hectare. Start from the soil test, and if no standard grade fits, that is exactly when a custom blend costs less overall despite a higher price per tonne.
Not sure how to read the three numbers? Reading an NPK ratio covers it.
What to ask any supplier
- Is it a true compound or a blend? Both are fine; they behave differently in the spreader
- Delivered or ex-works? The most common reason a quote looks cheap
- Granule size range and hardness — decisive above 24 m spreading width
- Certificate of Analysis for the delivered batch
- Chloride or sulphate form of potassium — matters for chloride-sensitive crops
What to send for a quote
- Analysis — the grade you want, or your soil test and we will match it
- Tonnage — and whether it is one delivery or several
- Packing — bulk, 1 t bulka bags, or 25 kg / 50 kg bags
- Delivery address — or destination port for export
- Unloading — what you can unload with on the day
Those five and the quote comes back complete rather than approximate. More on how a quote is built up in what drives your quote.
Tell us the analysis or send your soil test, with tonnage and delivery address. If a standard grade fits we will say so; if it does not, we will quote a blend.