Water soluble grades exist for one purpose: to go through an irrigation system or a sprayer rather than onto the ground. We stock 23 analyses. Choosing between them is mostly about the growth stage you are feeding and what your water will tolerate.
Matching the analysis to the stage
| Stage | Analysis shape | Why |
|---|---|---|
| Establishment | Phosphorus-led, e.g. 10-52-10 | Root development, when phosphorus placement is hardest to achieve any other way |
| Vegetative growth | Nitrogen-led or balanced, e.g. 20-20-20 | Canopy and frame |
| Fruit fill and finish | Potassium-led, e.g. 5-7-44, 5-10-40 | Potassium drives size, sugar, colour and shelf life — demand peaks late |
| Correcting mid-season | Whatever the tissue test says | Fertigation is the fastest way to respond within a season |
The high-potassium grades are the ones horticulture buys most, because potassium demand peaks exactly when the crop is least able to take it up from dry soil.
What to check before buying
Solubility and residue
The whole point is that it dissolves completely and leaves nothing behind. Residue blocks filters and drippers, and clearing a blocked system costs more than the fertiliser saved. Ask for the solubility figure, and always jar-test a new product with your own water before it goes near the mainline.
Your water
Hard water high in calcium and magnesium can precipitate with phosphate and sulphate grades. Water quality decides which analyses are usable on your site — it is not the same answer everywhere.
Compatibility
Calcium products and sulphate or phosphate products do not belong in the same tank. Use separate tanks and inject separately.
Chloride
On chloride-sensitive crops the potassium source matters as much in fertigation as in the ground — see SOP vs MOP.
Soluble or granular?
Soluble grades cost more per unit of nutrient than granular ones. They earn it where you have irrigation infrastructure, need precise timing through the season, or are feeding a high-value crop where a mid-season correction pays for itself. They do not earn it as a general replacement for granular fertiliser on broadacre ground — the full comparison is in water-soluble or granular.
Supply
Our 23 water-soluble analyses are supplied in 25 kg bags, which is how fertigation product is normally drawn down, and in bulka bags for larger operations. Minimum order 10–25 MT depending on product and destination. Every analysis has a free technical data sheet.
Keep it dry and sealed. Soluble grades are more hygroscopic than granular ones and will cake solid in an open bag.
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 the crop and stage, the tonnage and your delivery address. Ask for the data sheet and jar-test it with your own water first.