Lavender, admired for its blooms and aroma, is a fragrant and drought-tolerant plant. A Mediterranean native, it thrives in lean, well-draining soil. With naturally low nutrient requirements, fertilizer applications are often unnecessary or require careful use.
Understanding Lavender’s Nutritional Needs
Lavender prefers poor, alkaline to neutral soil, typically with a pH between 6.7 and 7.5. Providing too much nitrogen can lead to excessive foliage growth at the expense of flower production. This lush, soft growth can also make the plant more susceptible to diseases and reduce its winter hardiness.
Lavender typically obtains sufficient nutrients from its environment. However, if soil is deficient, phosphorus may aid flowering, and potassium can support overall plant health. Good drainage and proper pH are far more important for lavender’s success than high soil fertility.
Choosing the Right Fertilizer
If your lavender plants show signs of nutrient deficiency, or if a soil test indicates a specific need, choose a fertilizer with a low nitrogen content. Options like bone meal (rich in phosphorus) or wood ash (providing potassium and maintaining alkaline pH) are suitable organic choices.
Slow-release granular fertilizers or balanced formulas with NPK ratios such as 5-10-10 or 0-10-10 can also be considered. These formulations provide less nitrogen, promoting blooms rather than just leafy growth. Avoid high-nitrogen fertilizers, like those for lawns, as they can harm lavender.
When and How to Fertilize
If fertilizing, the optimal time is early spring as new growth emerges. Annual fertilization is often not required for established plants.
Spread granular fertilizers or a thin layer of compost around the plant’s drip line (the outer edge of its foliage). Liquid fertilizers should be diluted according to product instructions to prevent nutrient overload. Always water the area thoroughly after applying any fertilizer to help distribute the nutrients into the soil and prevent root burn. Avoid direct contact with the plant’s base or foliage to prevent damage.
Signs of Nutrient Imbalance
Observing your lavender can reveal nutrient issues. Signs of deficiency, though rare, include stunted growth or pale, yellowing older leaves. However, these symptoms can also indicate other problems like improper watering or pH.
Conversely, an excess of nutrients, especially nitrogen, often manifests as overly lush, leggy growth with few or no flowers. Yellowing leaves that appear burned at the tips or margins, or a white crust forming on the soil surface, can signal over-fertilization and root damage. If a nutrient imbalance is suspected, a professional soil test can provide precise information.