From our roots outward, we lavender plants are Mediterranean natives, adapted to thrive in lean, gritty, and often nutrient-poor soils. Our primary request is not for rich feeding but for excellent drainage and abundant sunlight. An excess of nutrients, particularly nitrogen, is detrimental to our well-being. It forces an aggressive but weak growth of foliage at the expense of the precious essential oils that give us our signature fragrance. This soft, lush growth is highly susceptible to disease and winter damage, and it compromises the intensity and quantity of our flowers. Our ideal diet is a balanced, gentle, and minimal one.
When supplemental feeding is necessary, the formulation of the fertilizer is critical. We respond best to a fertilizer with a balanced or slightly higher phosphorus ratio. A formula labeled as 4-6-4, 5-5-5, or 7-7-7 is ideal. The first number (Nitrogen) promotes green leaf growth, which we need only in moderation. The second number (Phosphorus) is crucial as it supports the development of strong root systems and, most importantly, prolific and vibrant blooming. The third number (Potassium) ensures our overall vigor and hardiness, helping us withstand environmental stresses. Organic options like well-composted manure, bone meal (for phosphorus), or a balanced organic plant food are excellent choices as they release nutrients slowly, mirroring our natural preference for a gentle nutrient availability.
Timing your feeding is as important as what you feed us. The single most beneficial time to provide a light meal is at the very beginning of our active growing season, in early spring as new growth emerges from our woody base. This single application gives us a gentle boost to kickstart the season's growth and flower production. A second, very light feeding can be applied immediately after you have harvested or deadheaded our spent flower spikes, to help us recover energy. However, you must absolutely cease all fertilization by mid-summer, at least two months before the first expected frost in your region. Fertilizing too late stimulates tender new growth that will not have time to harden off, making it highly vulnerable to freezing and dying back over the winter.
The method of application ensures the nutrients are available to our roots without causing harm. Always apply fertilizer to soil that is already moist to prevent root burn. Sprinkle the recommended amount of granular fertilizer lightly around our drip line (the circumference of our foliage), taking great care to keep it away from our main stem. Then, water it in thoroughly to help the nutrients percolate down to our root zone. For liquid fertilizers, dilute them to half or even a quarter of the recommended strength on the label. Remember, the rule for feeding lavender is always "less is more." When in doubt, it is far safer to under-fertilize than to over-fertilize.
