Watering mature lavender plants may occur after significant vegetation or flowers have been removed in late summer or early fall, or when the soil becomes powdery, hard or unseasonably dry. Harvesting and heavy pruning remove a large part of the plant's water and nutrients held in the vegetation. Most commercial growers irrigate during the July and August months when harvesting has occurred and the soils tend to be dry. The plant benefits from irrigation in these conditions because the growing season is still occurring and the plant continues to grow new tender vegetation for its nutritional needs. Remember, lavender does not dislike water; it dislikes “wet feet.” Tend to let the soil go dry between irrigation cycles. Young and tender plants require vigilance. The soil moisture around tender plants should always feel like a “wrung out sponge” until the fall and winter rains have appeared. A soggy soil is lethal to young and tender plants, as is a rock hard or powdery soil.
Generally, regular watering is not required in late fall, winter, spring and early summer for established plants. Ground moisture, seasonal rains and dew sustain the plant. However, maintaining adequate moisture around the root base of newly installed and young plants is important until the plant has established its root system more fully and the fall and winter rains have moistened the soil.
Information excerpt from Dr. Lavender's Owner's manual and is provided by the Sequim Lavender Company, Sequim, WA. All rights reserved.