Oxygen restriction describes a root-zone condition where air cannot move through the potting mix fast enough, even though moisture is present. Roots lose function not because of excess water, but because oxygen is displaced for too long.
When air spaces stay filled with water or collapse due to fine particles, oxygen diffusion slows and root respiration drops. As roots weaken, water and nutrient uptake decline, leading to symptoms like limp leaves, yellowing, stalled growth, or flower failure while the mix still feels wet.
Oxygen restriction is not the same as overwatering and is not a diagnosis by itself. It is a failure pathway that explains how mix structure, slow dry-down, and low indoor water use lead to root-zone failure.
In short, oxygen restriction explains why plants can decline in wet pots even when watering seems reasonable.
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