Monday, September 1, 2025

fertigasion system

 fertigasion system


 formulation (nutrition)

For example, a general fertigation target for fruiting vegetables (like tomato, cucumber, chili) is:

  • Nitrate-N (NO₃⁻): 150–200 ppm

  • Ammonium-N (NH₄⁺): 5–15 ppm

  • Phosphorus (P): 40–60 ppm

  • Potassium (K): 250–350 ppm

  • Calcium (Ca): 150–200 ppm

  • Magnesium (Mg): 40–60 ppm

  • Sulfur (S): 60–100 ppm

  • Micros (Fe, Mn, Zn, Cu, B, Mo) in ppm ranges

Usually, this is made using two stock solutions:

  • Tank A: Calcium nitrate + iron chelate (Fe-EDDHA)

  • 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

  • Crop: Ginger / Turmeric (rhizome crop, moderate-to-high K demand).

  • Target final nutrient concentrations in irrigation water (elemental ppm):

    • 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.

  • 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.

  • Fertilizer products used (typical soluble salts) and their elemental compositions used for the calculations:

    • Calcium nitrate (Ca(NO₃)₂·4H₂O) — N 15.5% (all NO₃), Ca 19%.

    • Potassium nitrate (KNO₃) — N 13%, K ≈ 38.2% (K from K₂O conversion).

    • Mono-potassium phosphate (MKP, KH₂PO₄) — P ≈ 22% (elemental P), K ≈ 28%.

    • Magnesium sulfate heptahydrate (MgSO₄·7H₂O) — Mg ≈ 9.86%, S ≈ 12% (approx).

    • Potassium sulfate (K₂SO₄) — used to supply remaining S/K without adding N. (K ≈ 43.2%, S ≈ 18%).

  • 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)

  • Tank A: only calcium nitrate + iron chelate (Ca and NO₃ separated from PO₄ / SO₄ sources to avoid precipitation).

  • 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)

  • Calcium nitrate (Ca(NO₃)₂·4H₂O): 39.5 kg (≈ 39,500 g)

    • This supplies the calcium and a portion of the N.

  • Fe-chelate (water-soluble; e.g., Fe-EDTA / Fe-EDDHA): 1.5 – 2.0 kg (commercial chelate).

    • 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.)

Tank A total solids: ~40–41 kg per 100 L (very concentrated). Dissolve in warm water and stir.

Tank B (100 L)

  • Mono-potassium phosphate (MKP, KH₂PO₄): 9.09 kg (≈ 9,091 g) — supplies P and some K.

  • Magnesium sulfate heptahydrate (Epsom salt): 20.28 kg (≈ 20,284 g) — supplies Mg and S.

  • Potassium sulfate (K₂SO₄): 3.14 kg (≈ 3,144 g) — used to top up S without adding N.

  • Potassium nitrate (KNO₃): 15.96 kg (≈ 15,960 g) — supplies remaining K and the rest of N.

  • 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)

  • N ≈ 150 ppm (slightly above 150 by ~5–10% depending on rounding)

  • P ≈ 40 ppm

  • K ≈ 200 ppm

  • Ca ≈ 150 ppm

  • Mg ≈ 40 ppm

  • 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:

  1. 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.

  2. 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)

  1. 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.

  2. Order:

    • Tank A: dissolve Ca(NO₃)₂ completely, then add Fe-chelate last (mix).

    • Tank B: dissolve MKP first, then KNO₃, then MgSO₄, then K₂SO₄, then micros (if powders, dissolve fully).

    • Never mix Tank A and Tank B in the same container — they are kept separate.

  3. Injection: use proportional injector set to 1:500 (or whichever ratio you choose). Check injection with a conductivity meter.

  4. 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).

  5. 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.

  6. Safety: wear gloves, goggles, and avoid inhaling dust. Large quantities here are concentrated — treat like chemicals.

Notes, caveats and next steps

  • 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).

  • 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.

  • 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).

  • 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)

  • Tank A (100 L):

    • Calcium nitrate: 39.5 kg

    • Fe chelate (commercial): 1.5–2.0 kg

  • Tank B (100 L):

    • MKP (KH₂PO₄): 9.09 kg

    • MgSO₄·7H₂O: 20.28 kg

    • K₂SO₄: 3.14 kg

    • KNO₃: 15.96 kg

    • Micronutrient chelate mix: 150–300 g (or follow product label)

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