A hydroponic nutrient example is most useful when it does more than list fertiliser products. It should show how a working nutrient recipe becomes two stable stock solutions, how those solutions are injected into irrigation water, and how the finished feed is checked at the dripper. That is where nutrient planning becomes repeatable day-to-day operation.
The example below suits a small to medium recirculating or run-to-waste system where nutrient is made up continuously through a doser. It is an illustrative starting point, not a universal crop recipe. Crop type, water quality, growing media, climate, growth stage and drainage strategy all affect the final programme.
A practical hydroponic nutrient example
This example produces 1,000 litres of finished nutrient solution for a general fruiting crop programme at a moderate strength. It is intended as a simple illustration of stock tank separation and injector calculations, rather than a prescription for every crop.
For each 1,000 litres of finished feed, the target fertiliser inputs are 800 g calcium nitrate, 350 g potassium nitrate, 150 g monopotassium phosphate, 500 g magnesium sulphate and 60 g of a quality hydroponic trace element blend. Select products with a known analysis and use a trace blend formulated for hydroponic use.
At these rates, a practical arrangement is two 100-litre stock tanks dosed independently at 1 per cent. In each tank, dissolve the ingredients fully, then top up with water to the final 100-litre mark.
| Stock tank | Ingredients per 100 L of stock solution | Injection setting |
|---|---|---|
| Tank A | 8 kg calcium nitrate and 3.5 kg potassium nitrate | 1% |
| Tank B | 1.5 kg monopotassium phosphate, 5 kg magnesium sulphate and 600 g trace element blend | 1% |
At a 1 per cent setting, each injector delivers 10 litres of stock per 1,000 litres of irrigation water. Tank A therefore contributes 800 g of calcium nitrate and 350 g of potassium nitrate. Tank B contributes the remaining phosphate, magnesium sulphate and trace elements. Together, the two tanks make the intended 1,000-litre working solution.
The expected EC will depend heavily on the fertiliser grades and source-water EC. As a broad operational target, this type of programme may land around 1.8 to 2.2 mS/cm after allowing for the water supply. Verify it with a calibrated EC meter rather than assuming the calculated result is correct.
Why the nutrients are split into A and B tanks
Calcium nitrate must not be stored in a concentrated mix with sulphates or phosphates. Calcium can react with these materials and form insoluble solids. The result is sediment in the tank, blocked filters or emitters, inaccurate dosing and nutrients that are no longer available to the crop.
Keeping calcium nitrate in Tank A and magnesium sulphate and phosphate in Tank B avoids this common incompatibility. Potassium nitrate is generally compatible with calcium nitrate in an A tank at sensible stock concentrations, although water temperature and product solubility still matter.
Always add fertiliser to water, not water onto a pile of fertiliser. Keep agitation running where possible, allow each product to dissolve before adding the next, and make stock solutions to a final volume. A tank marked at 100 litres should contain 100 litres of finished stock, not 100 litres of water plus fertiliser.
Matching the nutrient example to your injector
The dosing ratio is as important as the recipe. A 1 per cent injector adds one part stock concentrate for every 100 parts of carrier water. In practical terms, that is 10 litres of stock per 1,000 litres of water.
The basic calculation is:
Stock volume required = irrigation water volume × injector percentage ÷ 100
If your irrigation system uses 5,000 litres during a cycle, each 1 per cent injector will draw 50 litres from its stock tank. With two injectors, the system draws 50 litres from Tank A and 50 litres from Tank B over that cycle.
A lower-ratio injector can still be used, but the stock concentration must increase to deliver the same nutrient mass. For example, an injector set at 0.5 per cent delivers only 5 litres per 1,000 litres. The stock would need to be twice as concentrated. That may be suitable for highly soluble products, but it can create problems if the concentrate approaches its solubility limit, particularly in a cool shed or during winter.
Conversely, a higher dosing percentage allows a weaker, easier-to-dissolve stock. The trade-off is greater stock volume, larger tanks and more product handling. The right solution depends on daily water use, available tank capacity, desired refill interval, injector ratio range and the chemical compatibility of the wetted components.
For commercial systems, check injector performance across the actual flow range. A unit that doses accurately at peak irrigation flow may not operate as intended during a low-flow flush cycle, a short zone run or when only one small bay is irrigating. Flow rate, pressure loss and back-pressure conditions all need to be considered during selection.
Set EC and pH at the point of use
The recipe tells you what should enter the water. EC and pH testing tell you what the plants actually receive.
Start by measuring source water EC and pH before any dosing. Bore water, dam water and town water can vary substantially, and bicarbonates in particular can make pH control more demanding. A source water EC of 0.2 mS/cm leaves far more room for nutrient than water already sitting at 0.8 mS/cm.
Measure the mixed solution downstream of the injection point, after sufficient contact and mixing time. Testing directly beside an injector can give a misleading result because the concentrate may not be evenly distributed through the line. In larger systems, sample at a representative dripper or from the return line.
For many hydroponic crops, a working pH around 5.5 to 6.2 is a common operating range. The best setpoint depends on crop and media. A pH of 5.8 is often a sensible starting point, but do not chase a single number if plant performance, drainage pH and nutrient uptake indicate a different setting is more appropriate.
Where acid is required to reduce pH, dose it separately from the nutrient stocks unless the formulation and equipment supplier specifically confirm compatibility. Concentrated acid mixed into a fertiliser stock can create safety risks and chemical instability. Select seals, hoses and injector materials that suit both the acid and the fertiliser solution.
Turn the example into a controlled operating routine
A nutrient programme becomes reliable when operators can repeat it without relying on memory. Record the product name, batch details, stock tank mix date, stock strength, injector setting, source-water EC, final EC and pH. If performance changes, those records make it far easier to identify whether the issue is water quality, mixing, calibration or crop demand.
Check injector draw rates periodically. Fill the stock tank to a measured level, run a known irrigation volume, then compare the expected draw with the actual amount used. A worn seal, blocked suction strainer, air leak or incorrect adjustment can shift nutrient strength well before plants show visible symptoms.
Filters also deserve attention. Undissolved fertiliser, contamination in tank water and precipitate from incompatible mixes can restrict filters and emitters. A clean filter is not just irrigation maintenance - it is part of nutrient accuracy.
Common mistakes that change the final feed
The most frequent error is calculating stock strength without allowing for the injector ratio. The second is putting incompatible fertilisers in the same concentrated tank. Other problems include mixing to an unknown tank volume, relying on uncalibrated EC or pH meters, and using an injector outside its specified flow range.
It is also easy to copy a recipe designed for rainwater and apply it to hard bore water. If the source water contains high bicarbonates, sodium or chloride, the fertiliser recipe may need adjustment before it is suitable for long-term use. A water analysis is worthwhile whenever a new site, bore or water source is introduced.
A proven dosing injector, suitable seals and properly sized stock tanks give the recipe a practical chance of performing as designed. For operators comparing ratios, flow ranges and chemical compatibility, AgriDosing can help match dosing equipment to the actual irrigation conditions rather than a nominal recipe.
Start with a small, measured batch, test the mixed solution at the dripper, and record the result. Once the system delivers the same EC and pH across several irrigation cycles, you have a dependable baseline that can be adjusted confidently as the crop and season change.