fertigasion system
formulation (nutrition)
For example, a general fertigation target for fruiting vegetables (like tomato, cucumber, chili) is:
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Nitrate-N (NO₃⁻): 150–200 ppm
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Ammonium-N (NH₄⁺): 5–15 ppm
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Phosphorus (P): 40–60 ppm
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Potassium (K): 250–350 ppm
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Calcium (Ca): 150–200 ppm
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Magnesium (Mg): 40–60 ppm
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Sulfur (S): 60–100 ppm
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Micros (Fe, Mn, Zn, Cu, B, Mo) in ppm ranges
Usually, this is made using two stock solutions:
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Tank A: Calcium nitrate + iron chelate (Fe-EDDHA)
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Tank B: Potassium nitrate, monopotassium phosphate, magnesium sulfate, trace elements
This prevents precipitation (e.g., calcium + sulfate/phosphate).
👉 Do you want me to build you a ready-to-use formulation recipe (grams of each fertilizer per 100L stock tank), based on your crop and system?
Great — below I made practical, ready-to-use stock solution recipes (Tank A & Tank B) for ginger / turmeric fertigation, with an injection ratio of 1:500 (1 L of stock → 500 L irrigation water).
I had to make a few standard assumptions (stated so you can change them if needed). If any assumption is wrong for your setup, tell me and I’ll recalc immediately (no waiting).
Assumptions I used
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Crop: Ginger / Turmeric (rhizome crop, moderate-to-high K demand).
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Target final nutrient concentrations in irrigation water (elemental ppm):
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N = 150 ppm, P = 40 ppm, K = 200 ppm, Ca = 150 ppm, Mg = 40 ppm, S = 60 ppm.
These are typical, balanced values for rhizome/vegetable crops — conservative and safe for greenhouse/field fertigations.
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Injection ratio: 1:500 (common, conservative). You can change to 1:250 or 1:100 — if you do, tell me and I’ll re-calc.
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Fertilizer products used (typical soluble salts) and their elemental compositions used for the calculations:
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Calcium nitrate (Ca(NO₃)₂·4H₂O) — N 15.5% (all NO₃), Ca 19%.
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Potassium nitrate (KNO₃) — N 13%, K ≈ 38.2% (K from K₂O conversion).
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Mono-potassium phosphate (MKP, KH₂PO₄) — P ≈ 22% (elemental P), K ≈ 28%.
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Magnesium sulfate heptahydrate (MgSO₄·7H₂O) — Mg ≈ 9.86%, S ≈ 12% (approx).
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Potassium sulfate (K₂SO₄) — used to supply remaining S/K without adding N. (K ≈ 43.2%, S ≈ 18%).
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Micronutrients: I recommend a commercial water-soluble chelated micro mix rather than trying to hand-mix tiny element salts in stock. I give guidance below.
If your irrigation water has high hardness / Ca / alkalinity, or your source EC/pH are unusual, these numbers should be adjusted — test your water first.
The plan / mixing logic (why A & B)
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Tank A: only calcium nitrate + iron chelate (Ca and NO₃ separated from PO₄ / SO₄ sources to avoid precipitation).
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Tank B: KNO₃ + MKP + MgSO₄ + K₂SO₄ + micros.
This separation avoids Ca + phosphate/sulfate precipitation in the stock tanks.
Calculated recipe — per 100 L of each stock tank (A and B)
These numbers are “per 100 L of tank solution”. When using 1:500 injection, 100 L of stock feeds 50,000 L irrigation water.
Tank A (100 L)
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Calcium nitrate (Ca(NO₃)₂·4H₂O): 39.5 kg (≈ 39,500 g)
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This supplies the calcium and a portion of the N.
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Fe-chelate (water-soluble; e.g., Fe-EDTA / Fe-EDDHA): 1.5 – 2.0 kg (commercial chelate).
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Use a strong Fe chelate (EDDHA if alkaline water) at manufacturer’s recommended chelate rate to supply ~2 ppm Fe in final irrigation. (I give micro guidance below.)
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Tank A total solids: ~40–41 kg per 100 L (very concentrated). Dissolve in warm water and stir.
Tank B (100 L)
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Mono-potassium phosphate (MKP, KH₂PO₄): 9.09 kg (≈ 9,091 g) — supplies P and some K.
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Magnesium sulfate heptahydrate (Epsom salt): 20.28 kg (≈ 20,284 g) — supplies Mg and S.
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Potassium sulfate (K₂SO₄): 3.14 kg (≈ 3,144 g) — used to top up S without adding N.
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Potassium nitrate (KNO₃): 15.96 kg (≈ 15,960 g) — supplies remaining K and the rest of N.
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Micronutrient mix (commercial water-soluble chelated mix): 150 – 300 g (see explanation).
Tank B total solids: ~48–50 kg per 100 L (also concentrated).
What final irrigation concentrations you get (when 1:500 injection is used)
(approximate, elemental ppm in irrigation water)
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N ≈ 150 ppm (slightly above 150 by ~5–10% depending on rounding)
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P ≈ 40 ppm
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K ≈ 200 ppm
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Ca ≈ 150 ppm
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Mg ≈ 40 ppm
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S ≈ 60 ppm
(These are the targets I used and the recipe was sized to achieve them. Expect small rounding differences; always measure EC and element ppm after mixing to confirm.)
Micronutrients (Fe, Mn, Zn, Cu, B, Mo) — practical recommendation
Mixing micro salts from raw sulfates/oxides is possible but error-prone and can cause precipitation. Two practical options:
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Use a commercial chelated micros product (preferred). Typical label rates of solubles are ~100–300 g per 100 L of stock A or B depending on product strength — I suggested 150–300 g /100 L in Tank B. Pick a product with Fe (as EDDHA or EDTA), Mn, Zn, Cu, B, Mo in water-soluble chelated form. That reliably gives roughly Fe 1–3 ppm, Mn 0.5–1 ppm, Zn/Cu 0.05–0.5 ppm, B ~0.2–0.5 ppm in final irrigation.
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If you want exact element grams, tell me which micronutrient salts you have (e.g., Fe-EDDHA %, ZnSO₄, MnSO₄, CuSO₄, Boric acid, Na₂MoO₄) and I’ll calculate exact grams per 100 L stock to meet explicit ppm targets. (I avoided that above because typical home/greenhouse mixes vary wildly and trace element percent assumptions can cause big errors.)
Mixing & use instructions (critical)
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Make each tank in plain clean water (start with ~70–80 L water for 100 L batch, dissolve solids, then top to 100 L). Use warm water to help dissolve.
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Order:
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Tank A: dissolve Ca(NO₃)₂ completely, then add Fe-chelate last (mix).
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Tank B: dissolve MKP first, then KNO₃, then MgSO₄, then K₂SO₄, then micros (if powders, dissolve fully).
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Never mix Tank A and Tank B in the same container — they are kept separate.
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Injection: use proportional injector set to 1:500 (or whichever ratio you choose). Check injection with a conductivity meter.
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Measure: always measure EC and pH of the final mixed irrigation water and test Na, Ca, Mg if possible. Adjust pH to ~5.8–6.5 for best nutrient availability (especially for hydroponic/greenhouse).
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Storage: keep stock tanks out of direct sun, at moderate temperature. Use within weeks — MgSO₄ and MKP are stable; chelates can degrade if stored hot/alkaline.
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Safety: wear gloves, goggles, and avoid inhaling dust. Large quantities here are concentrated — treat like chemicals.
Notes, caveats and next steps
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The masses above are concentrated because they are for 1:500 injection. If you use a stronger injection (1:100), reduce the stock masses proportionally (for 1:100, multiply these masses by 100/500 = 0.2).
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If your irrigation water already contains substantial Ca, Mg, or K (hard water), you must reduce the stock accordingly. Please test your source water (EC, ppm of Ca, Mg, Na, initial pH) — I can then recalculate exact tank recipes that subtract what's already present.
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If you prefer smaller, easier-to-handle stock strengths, we can redesign for 1:250 or 1:100 injection (so per-100 L numbers drop).
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If you want exact micro salt grams (boric acid, zinc sulfate, manganese sulfate, copper sulfate, sodium molybdate, Fe-EDDHA) rather than a commercial micro mix, send me the specific products and their element percentages and I’ll compute per-100 L values.
Quick summary (rounded numbers per 100 L stock)
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Tank A (100 L):
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Calcium nitrate: 39.5 kg
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Fe chelate (commercial): 1.5–2.0 kg
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Tank B (100 L):
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MKP (KH₂PO₄): 9.09 kg
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MgSO₄·7H₂O: 20.28 kg
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K₂SO₄: 3.14 kg
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KNO₃: 15.96 kg
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Micronutrient chelate mix: 150–300 g (or follow product label)
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