养分锁定是指植物无法从生长介质或营养液中吸收一种或多种矿物质，即使这些养分实际存在。它通常是由不正确的pH值、过高的EC值或矿物离子之间的拮抗作用引起的，这些因素会阻止吸收。
关键事实
- Most common cause: pH outside the optimal range (5.5–6.5 in hydroponics)
- High EC can create osmotic stress that prevents water and nutrient uptake
- Mineral antagonism: excess calcium blocks magnesium; excess phosphorus blocks zinc and iron
- Symptoms mimic deficiency — yellowing, curling, or discolouration — despite adequate nutrients
- Fix: flush roots with pH-balanced plain water, then reintroduce nutrients at correct pH and EC
- Prevention: test pH and EC daily; change reservoir solution every 2–3 weeks