What is the primary effect of overwatering plants?

Overwatering plants is primarily detrimental because it leads to root rot and can drown plants. When the soil is saturated with excess water, it reduces the amount of oxygen available to the roots. Roots need oxygen to carry out essential functions, including respiration and nutrient uptake. When they are deprived of oxygen for extended periods, they can start to decay, a condition known as root rot. This condition not only harms the root system but can also lead to the death of the plant as it becomes unable to absorb water and nutrients effectively. Recognizing the signs of overwatering, such as yellowing leaves or a foul smell from the soil, is crucial for preventing serious damage to plant health.

The other options suggest outcomes that are not typically associated with overwatering. Increased growth rate and enhanced blooming potential usually occur with proper watering practices, while improved soil fertility is generally a result of organic amendments rather than excess water.