Which condition exacerbates the risk of root rot in nursery plants?

Overwatering is a significant factor that exacerbates the risk of root rot in nursery plants. When plants receive more water than they need, the soil becomes waterlogged, reducing the oxygen available to the roots. Roots require oxygen to function properly, and excessive moisture creates an environment conducive to the growth of pathogens, particularly fungi that thrive in saturated soil. These fungi can attack and decay the root tissue, leading to root rot, which ultimately can result in plant decline or death if not managed properly.

While inconsistent watering can lead to stress in plants, it does not directly create the conditions that favor root rot as consistently as overwatering does. Insufficient light can hinder growth and lead to poor plant health, but it is not a primary cause of root rot. Pest infestations can cause damage to roots and possibly lead to stress conditions, but again, it is the overwatering that creates the immediate environment for root rot to develop. Thus, overwatering stands out as the main condition that directly exacerbates the risk of root rot.