Lavender is cherished for its silvery-green foliage, fragrant blooms, and remarkable drought tolerance. Unlike many plants that thrive on rich soil and regular feeding, lavender is a Mediterranean species that naturally prefers an environment of neglect. Fertilization is not a routine task but a specific, sparingly applied supplement used only to address nutrient deficiencies or support intensive growth cycles. Understanding the plant’s specific needs dictates what to use and, most importantly, when to apply it.
Lavender’s Preference for Lean Soil
Lavender plants originate from dry, rocky regions and are genetically programmed to flourish in lean conditions. Their ideal environment is a well-draining, slightly alkaline soil, typically with a pH between 6.5 and 7.5. This preference establishes the rule that established lavender requires minimal to no supplemental feeding. Providing rich soil or applying excessive nutrients, particularly nitrogen, works against the plant’s natural tendencies. Too much nitrogen encourages lush, soft foliage at the expense of flower production, resulting in leggy growth and a reduced concentration of essential oils. Over-fertilization can also compromise the plant’s hardiness, increase susceptibility to disease, and potentially damage the root system.
Optimal Timing for Supplemental Feeding
The timing of any application is important for precise, minimal feeding.
In-Ground Plants
For plants grown directly in the ground, a single, light feeding early in the spring is usually sufficient. This should occur just as new growth emerges from the woody stems, but after the last expected frost, providing a boost for the growing season. A second opportunity for light fertilization occurs immediately following a major pruning, typically after the first main flush of flowers has faded. Applying nutrients at this time helps the plant recover and supports the development of new, healthy branching. The goal is to assist the plant in setting new flower buds without stimulating excessive vegetative growth late in the season, which could reduce winter hardiness.
Potted Plants
Potted lavender plants are the exception because nutrients in their confined soil leach out quickly with each watering. Container-grown specimens require a more frequent, though still light, feeding schedule. A half-strength liquid fertilizer can be applied monthly throughout the active growing season. Alternatively, a controlled-release granular product can be used at the beginning of spring and potentially again in early summer to sustain growth.
Choosing the Right Fertilizer and Application Method
When selecting a product, choose a low-nitrogen formula, indicated by the first number in the NPK ratio. Instead of a typical balanced fertilizer like 10-10-10, lavender benefits more from ratios such as 5-10-10 or lower-analysis organic options. These formulas provide a greater proportion of phosphorus and potassium, which support robust root development, flower production, and overall plant strength. The best application technique for established plants is to use a slow-release granular fertilizer or well-aged compost. Lightly scratch this material into the soil surface around the plant’s drip line (the outer perimeter of the canopy). Keep the fertilizer away from the woody crown of the plant to prevent chemical burn. If a soil test indicates the pH is too acidic, dolomite lime or wood ash can be lightly incorporated during the spring feeding to help raise the alkalinity.