Lemongrass, a fragrant, tropical grass native to Southeast Asia, is prized for its culinary and aromatic qualities. This perennial plant thrives in conditions that mimic its warm, humid homeland, meaning its preference for consistent soil moisture is a defining trait for healthy growth. Establishing the right watering routine is paramount, as the plant will quickly suffer if the soil becomes either waterlogged or completely dry. The goal is to encourage the vigorous growth that produces the thick, flavorful stalks used in cooking.
Establishing the Baseline Watering Schedule
The general rule for watering lemongrass during its peak summer growing season is to maintain evenly moist, but not saturated, soil. Lemongrass requires consistent moisture, especially when temperatures are high and it is actively producing foliage. To determine if watering is necessary, use the finger test: insert a finger about one inch deep into the soil near the plant base.
If the soil feels dry at this depth, water thoroughly. Under ideal growing conditions, such as a sunny location with well-draining soil during a hot summer, this may translate to watering every two to three days. In extremely hot or arid climates, or during a heat wave, the plant may require water daily to prevent stress.
Factors That Adjust Watering Frequency
The environment significantly dictates how often you need to water. Plants grown in containers dry out much faster than those planted directly in the ground because the soil volume is limited. A large containerized lemongrass plant may need daily watering during the height of summer, while an in-ground plant may only need it every few days.
Climate plays a large role, as both temperature and humidity affect the rate of water loss. Hot, windy, and dry weather rapidly pulls moisture from the soil and leaves, necessitating more frequent watering. Conversely, high humidity or consistent rainfall reduces the need for manual irrigation. When temperatures drop in the fall and winter, lemongrass goes into a semi-dormant phase, requiring a drastic reduction in water. Overwintered plants need only occasional watering to prevent the roots from completely drying out.
Proper Watering Application and Depth
When watering, focus on deep saturation of the root zone rather than light, shallow sprinkling. Deep watering encourages the development of a robust and deep root system, which makes the plant more resilient to short periods of drought. To achieve this, water slowly until you see it begin to pool on the surface or drain out of the container’s bottom holes.
Good drainage is equally important because while the plant loves moisture, it is highly susceptible to root rot in waterlogged conditions. Always apply water directly to the soil at the base of the plant, avoiding the foliage, as keeping the leaves dry helps prevent fungal issues.
Recognizing Signs of Water Stress
Observing the plant’s foliage is the most reliable way to diagnose whether your watering routine is balanced. Underwatering typically presents as a noticeable wilting or drooping of the leaves, where the foliage appears limp and may develop dry, brown, or crispy tips and edges. The soil will often be visibly dry and may pull away from the edges of a pot.
Overwatering can cause the leaves to wilt because the saturated soil leads to root rot, which prevents the roots from taking up water. Overwatered leaves often turn yellow, starting from the base of the plant, and may feel soft or mushy. A perpetually soggy base or the presence of mold on the soil surface are clear signs of excessive moisture around the roots.