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Basic Feed Recipe Targets for Common Horticultural Crops

This page provides baseline nutrient targets for common horticultural crops grown in fertigation or substrate systems.

These values are intended as starting points, not fixed prescriptions.


Important notes before using these targets

  • Targets are given as elemental concentrations (mg/L)
  • Assumes reasonably balanced raw water
  • Assumes good root-zone oxygen and drainage
  • Targets should be adjusted for:
  • Growth stage
  • Climate and VPD
  • Yield vs vegetative balance
  • Cultivar sensitivity

Always interpret plant response before changing recipes.


General macronutrient ranges (context)

Element Typical range (mg/L)
Nitrogen (total) 120–200
Nitrate-N 100–180
Ammonium-N 5–15
Potassium 180–300
Calcium 120–200
Magnesium 30–60
Phosphorus 30–60
Sulphur 40–80

Micronutrient Target Ranges (General)

The following micronutrient targets are suitable for most horticultural crops grown in substrate or fertigation systems.

Values are expressed as elemental concentrations (mg/L) in the final feed solution.

Element Target range (mg/L) Notes
Iron (Fe) 1.5 – 3.0 Always supply chelated; requirement increases at high pH
Manganese (Mn) 0.5 – 1.0 Availability decreases at high pH
Zinc (Zn) 0.05 – 0.15 Excess P can reduce uptake
Copper (Cu) 0.03 – 0.10 Narrow safety margin
Boron (B) 0.3 – 0.6 Critical for fruit set; toxicity risk if excessive
Molybdenum (Mo) 0.05 – 0.10 Availability increases with pH
Chloride (Cl) 0.5 – 2.0 Usually supplied via water; avoid accumulation
Nickel (Ni) 0.005 – 0.02 Rarely limiting; required for urease activity

Notes - Iron chelate choice must match system pH
- Micronutrient issues are more often caused by availability than supply
- Over-application causes more damage than mild deficiency


Tomato (glasshouse / substrate)

Balanced for fruiting, calcium transport, and quality.

Element Target (mg/L)
Nitrate-N 140
Ammonium-N 8
Phosphorus 40
Potassium 260
Calcium 180
Magnesium 45
Sulphur 65

Micronutrient notes - High sensitivity to iron and boron - Iron deficiency common under high bicarbonate - Avoid excessive copper


Cucumber

Higher vegetative demand, lower Ca stress risk than tomato.

Element Target (mg/L)
Nitrate-N 160
Ammonium-N 10
Phosphorus 45
Potassium 240
Calcium 150
Magnesium 40
Sulphur 60

Micronutrient notes - Generally tolerant - Balanced iron and manganese support steady growth


Pepper (Capsicum)

More sensitive to stress and EC than tomato.

Element Target (mg/L)
Nitrate-N 140
Ammonium-N 6
Phosphorus 40
Potassium 240
Calcium 170
Magnesium 45
Sulphur 60

Micronutrient notes - Narrow tolerance for iron and manganese - Stress rapidly amplifies micronutrient imbalance


Strawberry (substrate)

Lower EC tolerance, high calcium sensitivity.

Element Target (mg/L)
Nitrate-N 120
Ammonium-N 6
Phosphorus 35
Potassium 200
Calcium 150
Magnesium 40
Sulphur 55

Micronutrient notes - Highly sensitive to boron and iron - Sodium and bicarbonate strongly affect uptake - Chelate choice is critical


Lettuce (protected cropping)

Fast turnover, shallow roots, low salt tolerance.

Element Target (mg/L)
Nitrate-N 130
Ammonium-N 10
Phosphorus 45
Potassium 190
Calcium 140
Magnesium 35
Sulphur 50

Micronutrient notes - Sensitive to iron and manganese deficiency - Copper toxicity risk in recirculating systems


Soft fruit (raspberry / blueberry – indicative)

Wide variation by system and cultivar.

Element Target (mg/L)
Nitrate-N 100–130
Ammonium-N 5–10
Phosphorus 30–40
Potassium 180–220
Calcium 120–160
Magnesium 35–45
Sulphur 50–65

Micronutrient notes - Iron availability often limiting - Blueberries extremely sensitive to pH-driven lock-up - Avoid chloride accumulation


Interpreting and Adjusting Targets

Increase cautiously when

  • Radiation sum is high
  • VPD is optimal
  • Root health is strong
  • Uptake matches demand

Reduce or stabilise when

  • EC accumulates in drain
  • Uptake drops unexpectedly
  • Stress symptoms appear
  • Climate becomes limiting

Practical Micronutrient Management Principles

  • Micronutrient problems are usually availability issues, not lack of supply
  • pH drift causes more issues than incorrect dosing
  • Always consider raw water contribution
  • Use chelates appropriate to system pH
  • Avoid frequent changes — trends matter more than snapshots

Key Principles

  • Feed supports growth — it does not drive it
  • Climate and roots set the ceiling
  • Stability outperforms precision
  • Adjust gradually and observe response

A good recipe is one the plant can use consistently.