In hydroponics there is no soil to buffer mistakes. The nutrient solution is the root zone, and four numbers decide how the crop does.
| Parameter | Typical target | Why |
|---|---|---|
| pH | 5.5–6.5 | Outside this, nutrients lock out quickly |
| EC, leafy greens & herbs | ~1.2–2.0 mS/cm | Nutrient strength |
| EC, fruiting crops | ~2.0–3.5 mS/cm | Higher demand during fruiting |
| Solution temperature | 18–24 °C | Warm water holds less oxygen; root rot risk rises |
| Dissolved oxygen | above ~5–6 mg/L | Roots need to breathe |
Why the numbers drift
Plants take up water and nutrients at different rates, so the solution concentrates or weakens through the day. Uptake also shifts pH. Warm afternoons heat the reservoir and cut oxygen.
What automation does
- Inline EC and pH sensors measure continuously instead of once a day with a pen
- Dosing pumps add nutrient and pH correction to hold the set points
- Level sensors top up the reservoir and alarm when low
- Flow monitoring alerts immediately if a pump stops — critical in NFT
Hydroponic fodder
Fodder units sprout barley or maize for dairy cattle in about a week. The main failure is mould, driven by warm, humid, stagnant air — so humidity, temperature and irrigation timing are what to monitor.