Why does overwatering cause flowers to die?

When a potted flower is overwatered, water fills the soil pore spaces and replaces the air in the soil. At this point, outside air cannot enter either, resulting in a lack of oxygen in the soil. The respiration of the roots is hindered, their physiological functions decline, and the roots' ability to absorb water and nutrients is blocked.

At the same time, because the soil lacks oxygen, aerobic bacteria in the soil that decompose organic matter multiply and become highly active, increasing soil acidity. Because butyric acid bacteria and others become highly active, they produce a series of toxic substances such as hydrogen sulfide and ammonia, which directly poison the roots. Meanwhile, due to the lack of oxygen, the plant consumes a large amount of its soluble sugars and accumulates excessive amounts of substances such as alcohol, causing photosynthesis to drop greatly, and finally the flower dies of starvation.

In the practice of growing flowers, it is common to see cases where overwatering causes the roots of flowers to turn black and rot, drowning the plants. Therefore, when cultivating flowers, watering should be done in the right amount.