Carnations (Dianthus caryophyllus) are popular flowering plants known for their vibrant blooms and fragrant scent. However, improper watering can severely impact their health. From the plant's perspective, overwatering and underwatering disrupt physiological processes, leading to visible stress signs. Below, we explore these signs in detail.
Overwatering suffocates carnation roots, depriving them of oxygen and creating an environment conducive to root rot. Here are the key signs:
The lower leaves turn yellow first, as excess water inhibits nutrient uptake, particularly nitrogen. The plant sacrifices older leaves to conserve energy.
Paradoxically, carnations may wilt even when the soil is wet. This occurs because damaged roots cannot transport water to the stems and leaves.
Roots become mushy, brown, or black and emit a foul odor. Fungal pathogens like Pythium thrive in waterlogged soil, attacking the root system.
White mold on the soil surface or green algae indicates excessive moisture, further stressing the plant by competing for resources.
Underwatering deprives carnations of the hydration needed for photosynthesis and cell turgidity. The plant exhibits these distress signals:
Leaves lose moisture and become brittle, starting at the tips and edges. The plant conserves water by reducing transpiration.
New leaves and buds appear smaller, and flowering is delayed. The plant prioritizes survival over reproduction under water scarcity.
Leaves curl inward to minimize surface area and reduce water loss through transpiration.
Stems become hard and woody as the plant redirects resources to strengthen structural tissues, sacrificing softer growth.
Carnations adapt to water imbalances through specific physiological mechanisms:
The plant closes stomata to reduce water uptake, but this also limits CO2 absorption, slowing photosynthesis. Ethylene production increases, accelerating leaf drop.
Abscisic acid (ABA) levels rise, triggering stomatal closure to conserve water. The plant also produces deeper roots to seek moisture, if possible.
Carnations rely on their surroundings to signal water needs:
Soil remains soggy for days, and pots lack drainage. Humidity around the plant is excessively high, promoting fungal growth.
Soil pulls away from the pot edges, and the surface appears cracked. The pot feels unusually light when lifted.
