{{ fitSummary.headline || 'Recipe Sheet Ready' }}
{{ totalMassDisplay }}
{{ fitSummary.subline || 'Total fertilizer to dissolve for the working solution.' }}
{{ badge.text }}
{{ fitSummary.statusText }} {{ fitSummary.coverageText }}
Secondary view: {{ reservoirSecondaryDisplay }}.
ppm
ppm
ppm
{{ fertDisplayName(fert, idx) }}
%
%
%
{{ target_tolerance_percent }}%
1 :
g/L
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Fertilizer Amount Rate Suggested stock group N (ppm) P (ppm) K (ppm) Copy
{{ row.name }} {{ row.amountDisplay }} {{ row.rateDisplay }} {{ row.stockGroupDisplay }} {{ row.n_ppm.toFixed(1) }} {{ row.p_ppm.toFixed(1) }} {{ row.k_ppm.toFixed(1) }}
No fertilizers in the recipe yet.
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Nutrient Target (ppm) Achieved (ppm) Difference % of target Status Copy
{{ nutrient.label }} {{ nutrient.targetDisplay }} {{ nutrient.achievedDisplay }} {{ nutrient.deltaDisplay }} {{ nutrient.percentDisplay }} {{ nutrient.status }}
No nutrient fit data available.
Fit guidance:
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Fit notes will appear here when the recipe is calculated.
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Fertilizer Suggested stock group Stock density g for stock tank Stock feed Copy
{{ row.name }} {{ row.stockGroupDisplay }} {{ row.gramsPerStockLiterDisplay }} {{ row.gramsForTankDisplay }} {{ row.feedMlPerLiterDisplay }}
No stock readiness plan available.
Suggested stock group totals:
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{{ group.tankMassDisplay }} • {{ group.detail }}
Group totals appear after the stock plan is calculated.
Guidance notes:
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Recipe-specific guidance will appear here after calculation.
Mixing checklist:
  • {{ item }}
Checklist items will appear here when the recipe is ready.

                

            


            

                
Enter reservoir size, targets, and fertilizer grades to build a recipe sheet and stock-readiness plan.

            

        

    

                

                

                    

                        

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Fertilizer solution mixing is the job of turning nutrient targets in water into measured amounts of soluble fertilizer. That matters in hydroponics and fertigation because small differences in concentration can change growth rate, leaf quality, fruiting behavior, and salt stress more than the bag labels suggest.


  
Working-solution targets are usually discussed in parts per million, which in dilute nutrient solutions is the same practical idea as milligrams per liter. A target of 150 ppm nitrogen in a 100 L reservoir means you need 15 g of elemental nitrogen dissolved in the finished tank, not merely a fertilizer whose label happens to contain nitrogen somewhere in its analysis.


  
The complication is that fertilizer labels do not express every nutrient in elemental form. Nitrogen is listed directly, but phosphorus and potassium are commonly labeled as phosphate (P2O5) and potash (K2O). A usable mix therefore depends on converting those label numbers into elemental phosphorus and potassium before you compare them with final-solution targets.


  
A good recipe also has to respect the physical side of mixing. The final reservoir may be acceptable while the concentrate is too dense for the chosen injector setup, or two materials may be better kept apart when they are stored in strong stock solutions. That is why growers often think about two questions at once: what ends up in the final feed water, and how concentrated the stock tank has to be to deliver it.


  
An exact N-P-K match does not mean the whole nutrition plan is complete. Calcium, magnesium, sulfur, micronutrients, irrigation water chemistry, pH, electrical conductivity, crop stage, and product solubility still matter. A clean numerical fit is useful, but it is only one part of a workable feeding program.






  
Technical Details:


  
Nutrient mixing starts with elemental demand. Reservoir volume is converted to liters, each target concentration is treated as ppm or mg/L, and the required grams of N, P, and K are calculated for the finished tank. Fertilizer analyses then have to be translated into elemental fractions so each gram of product can be compared fairly against those requirements.


  
That conversion step is especially important for phosphorus and potassium. Commercial fertilizer grades commonly report phosphate as P2O5 and potash as K2O, while solution targets are usually stated as elemental P and K. The same labeled percentage therefore contributes less elemental nutrient than the oxide-style label number suggests.


  

    Diagram showing reservoir targets and fertilizer analyses flowing into a blend recipe and stock-plan check.
  


  
The primary mass balance used here is simple. For each nutrient, target concentration is multiplied by final-solution volume, then converted from milligrams to grams.


  

    
      
        
          mE
          =
          cE*V1000
        
        
          ∑jxjfj,E
          ≈
          mE, with xj≥0
        
      
    
  


  

    

      
      
        

          Symbol
          Meaning
          Unit or form
        

      
      
        

          V
          Reservoir volume after unit conversion
          L
        

        

          cE
          Target concentration for N, P, or K
          ppm or mg/L
        

        

          mE
          Required elemental mass in the finished tank
          g
        

        

          fj,E
          Elemental fraction supplied by fertilizer j
          g nutrient per g fertilizer
        

        

          xj
          Mass of fertilizer j used in the recipe
          g
        

      
    

  


  

    

      
      
        

          Label term
          How it is treated here
          Conversion
        

      
      
        

          N
          Already elemental nitrogen
          used directly
        

        

          P2O5
          Converted to elemental phosphorus before solving
          P = P2O5 x 0.4364
        

        

          K2O
          Converted to elemental potassium before solving
          K = K2O x 0.8301
        

      
    

  


  
If the selected fertilizer set can satisfy all active nutrient targets with non-negative weights, the result is marked as an exact fit. If not, the recipe becomes a constrained best-fit problem. The blend objective can keep all three nutrients balanced, or it can weight nitrogen, phosphorus, or potassium more heavily when an exact three-way match is impossible with the enabled grades.


  
The stock-planning side is derived from the finished recipe rather than solved separately. Injector ratio converts the working tank into the stock liters required for one reservoir fill, then each fertilizer amount is restated as stock density, grams for the chosen stock tank, and stock feed rate. The suggested stock grouping is a planning hint based on known presets and fertilizer names, not a complete chemistry model.


  

    

      
      
        

          Output cue
          Rule used here
          Why it matters
        

      
      
        

          Exact fit
          Every active nutrient lands within 0.1 ppm of target.
          The chosen grades can meet the requested N-P-K profile without compromise.
        

        

          Within tolerance
          Each active nutrient gap is less than or equal to the user-set tolerance percentage.
          The recipe misses at least one target slightly, but still stays inside the accepted band.
        

        

          Closest fit
          A non-negative blend exists, but one or more nutrient gaps exceed the tolerance band.
          The result is usable as a comparison point, not proof that the requested target can be met cleanly.
        

        

          Inside advisory load
          Combined stock load is less than or equal to the advisory guide.
          The concentrate density looks reasonable against the guide you chose.
        

        

          Dense concentrate
          Combined stock load is above the guide, but not above 1.25 times the guide.
          The stock may still be workable, but it deserves a solubility and compatibility check.
        

        

          Very dense concentrate
          Combined stock load is greater than 1.25 times the guide.
          The stock setup likely needs a larger tank, a lower injector ratio, or a split concentrate plan.
        

      
    

  






  
Everyday Use & Decision Guide:


  
A strong first pass is to choose the right Measurement system, set the real Reservoir volume, and use a Target profile only as a starting point. The built-in profiles are useful for loading a rough N-P-K pattern quickly, but they are not crop prescriptions. If you already have a known feed recipe, switch straight to Custom and enter your own nitrogen, phosphorus, and potassium targets.


  
The fertilizer rows are most helpful when you treat them like a comparison bench instead of a one-shot form. Load a known grade from Preset, adjust the percentages if your bag differs, and use Include in mix to compare combinations without deleting rows. That makes it easier to answer practical questions such as whether potassium nitrate plus monopotassium phosphate can cover the same target more cleanly than a general-purpose blend.


  
    
    
  • Use Balanced fit when you want the smallest overall N-P-K miss. Use Nitrogen first, Phosphorus first, or Potassium first when one nutrient matters more than the others for the current comparison.
    • 
    
  • Watch Fit Check before trusting the recipe. A clean-looking Recipe Sheet is not enough if one nutrient is still marked Above target or Below target.
    • 
    
  • Read Stock Readiness separately from nutrient fit. A recipe can hit N-P-K exactly and still ask for a concentrate that is too dense for your chosen injector ratio or too awkward for a single stock tank.
    • 
    
  • Treat Suggested stock group as a warning label, not a guarantee. It is there to slow you down around likely A/B separation issues, especially when calcium nitrate and phosphate- or sulfate-bearing salts appear together.
    • 
  


  
The most common misread is to assume an exact N-P-K fit means the feeding program is finished. It does not. This page does not solve for calcium, magnesium, sulfur, micronutrients, pH, EC, or water-source contributions, so a recipe that looks perfect on N, P, and K may still be incomplete or too aggressive in practice.


  
A sensible stopping point is the combination of Recipe Sheet, Fit Check, and Stock Readiness. If those three agree with your actual fertilizer labels and your real injector setup, then it makes sense to export CSV, DOCX, or JSON and move on to bench mixing, EC, pH, and small-batch checks.






  
Step-by-Step Guide:


  
Use the page in the same order you would plan a real feed mix: final tank first, fertilizer grades second, concentrate details last.


  
    
    
  1. Choose Measurement system, then enter Reservoir volume in liters, cubic meters, gallons, or quarts. The secondary volume display should immediately show the converted value in the opposite unit family.
    2. 
    
  2. Pick a Target profile or enter Target nitrogen (N), Target phosphorus (P), and Target potassium (K) directly. The top summary should stay empty until at least one nutrient target is above zero.
    3. 
    
  3. For each fertilizer row, choose a Preset or type your own name and analysis. Keep the row enabled only if that grade is genuinely part of the blend you want to test.
    4. 
    
  4. Open Advanced when the first-pass recipe is not enough. Set Blend objective, adjust Target tolerance, then enter the real Injector ratio, Stock tank size, and Advisory stock-load guide.
    5. 
    
  5. Read the summary box and Recipe Sheet first. You should see per-fertilizer amounts, working-solution rate, suggested stock group, and each fertilizer's N, P, and K contribution.
    6. 
    
  6. Open Fit Check and compare Target (ppm), Achieved (ppm), Difference, and Status. If the alert banner says a nutrient is not supplied, or the page reports Unable to find a non-negative fertilizer blend for the chosen targets., add a suitable fertilizer source or relax the target mix before going further.
    7. 
    
  7. Open Stock Readiness and Mixing Notes to review stock density, grams for the stock tank, feed rate, group totals, compatibility notes, and the mixing checklist. Export CSV, DOCX, or JSON only after those outputs match the real recipe you intend to mix.
    8. 
  






  
Interpreting Results:


  
Recipe Sheet tells you what to weigh. Fit Check tells you how close the chosen grades came to the requested N-P-K pattern. Stock Readiness tells you whether the same recipe still looks practical once it is restated as concentrate. Those are related answers, but they are not the same answer.


  
A high-confidence result is one where Fit Check is Exact fit or comfortably Within tolerance, the stock-load badge stays inside your guide, and the suggested stock grouping makes chemical sense for the products you are actually using. If one of those pieces disagrees, slow down and check the fertilizer analyses, injector ratio, and water-side limits before mixing a full batch.


  
The main overconfidence risk is to read the page as a complete nutrient-solution designer. It is not. The result only proves how well the enabled fertilizers can satisfy the N-P-K numbers you entered. It does not prove complete crop nutrition, safe stock-tank chemistry, or a good pH and EC outcome.


  
The best verification step is to compare the calculated recipe against the printed bag analyses, then confirm the mixed solution with your usual EC, pH, and small-batch observations. If the numbers look right but the crop or stock tank says otherwise, trust the real-world check over the neat ratio.






  
Worked Examples:


  

    
Example 1: default three-salt recipe lands exactly on target

    
Set Reservoir volume to 100 L and keep the default 150/50/200 ppm targets. Leave calcium nitrate 15.5-0-0, monopotassium phosphate 0-52-34, and potassium nitrate 13-0-46 enabled. The page returns roughly 66.5 g, 22.0 g, and 36.1 g in Recipe Sheet, for a total of about 124.6 g or 1.25 g/L.

    
Fit Check shows nitrogen, phosphorus, and potassium all On target, and the summary badge becomes Exact fit. With the default 1:100 injector and 20 L stock tank, Stock Readiness also shows one stock batch covering 20 reservoir fills. This is the clean nominal path: the fertilizer set can satisfy the requested N-P-K pattern without compromise.

  


  

    
Example 2: the nutrient fit is fine, but the concentrate warning changes

    
Keep the same 100 L exact-fit recipe, but lower Advisory stock-load guide from 250 g/L to 100 g/L. The recipe amounts do not change, because the guide does not affect the N-P-K solve. Fit Check still stays Exact fit.

    
Stock Readiness, however, now shows a combined stock load of about 124.6 g/L and labels it Dense concentrate. That is a useful edge case. It means the nutrient recipe is still mathematically correct, but the concentrate deserves a closer look for solubility, injector practicality, and possible A/B separation.

  


  

    
Example 3: a missing nutrient source triggers a hard stop

    
Disable every fertilizer except calcium nitrate 15.5-0-0 and keep the same 150/50/200 ppm target set. Nitrogen is still available, but phosphorus and potassium are not. The page does not guess or silently dilute the target. It stops with an error alert instead.

    
The visible messages are No enabled fertilizer supplies phosphorus (p). and No enabled fertilizer supplies potassium (k). The fix is to enable or add fertilizers that actually contribute those elements, then rerun Fit Check to see whether the new blend can reach the target cleanly.

  






  
FAQ:


  

    Why are my phosphorus and potassium targets elemental, but the fertilizer rows ask for P2O5 and K2O?
    
Because that matches how fertilizer labels are usually printed. The page converts fertilizer phosphate and potash values into elemental phosphorus and potassium before solving the recipe, so the final Fit Check stays in elemental ppm even when the bag label does not.

  


  

    Why does an enabled fertilizer sometimes show 0 g in Recipe Sheet?
    
An enabled row is allowed to stay in the comparison set even if the best-fit recipe does not need it. That does not mean the row is broken. It means the current targets can be met more cleanly without using that fertilizer, or that the objective weighted other nutrients more heavily.

  


  

    What does Closest fit mean in practice?
    
It means the enabled fertilizer grades cannot hit every active target inside the chosen tolerance while keeping all fertilizer masses non-negative. The page still returns the best available recipe, but at least one nutrient in Fit Check will remain outside the tolerance band and should be reviewed before you mix a full batch.

  


  

    Why am I seeing Unable to find a non-negative fertilizer blend for the chosen targets.?
    
That message appears when the requested N-P-K pattern cannot be built from the enabled grades without forcing one fertilizer amount below zero. Add a different nutrient source, change the target mix, or switch the Blend objective only after you confirm the bag analyses are entered correctly.

  


  

    Does the page send my recipe to a tool-specific backend?
    
Routine calculation happens in the browser and this page has no dedicated calculation backend. Keep in mind that changed settings are mirrored into the URL query string, and copied or downloaded CSV, DOCX, and JSON exports preserve the recipe outside the live page.

  


  

    Does an exact result mean the formula is agronomically complete?
    
No. It only means the enabled fertilizers can match the requested N-P-K values. You still need to check calcium, magnesium, sulfur, micronutrients, water contribution, pH, EC, stock compatibility, and crop response before treating the recipe as final.

  






  
Glossary:


  

    
ppm

    
Parts per million in the finished solution. In this context it is handled as mg/L.


    
P2O5

    
The phosphate form commonly used on fertilizer labels. It is converted to elemental phosphorus before the recipe is solved.


    
K2O

    
The potash form commonly used on fertilizer labels. It is converted to elemental potassium before the recipe is solved.


    
Injector ratio

    
The dilution relationship between concentrate and final feed water, written here in the form 1:x.


    
Stock tank

    
The concentrate reservoir used to feed the injector. The page estimates how much of each fertilizer belongs in that tank.


    
Non-negative blend

    
A recipe where every fertilizer amount is zero or greater. The solver will not use negative amounts to fake a target match.

  






  
References: