Fertilizer for Lavender: NPK Guide and Application Rates
Lavender thrives in poor, well-drained, alkaline soil and requires very little fertilizer. Over-feeding lavender is the primary cause of plant failure, as rich soil promotes soft growth susceptible to root rot and winter kill. Lean conditions produce the most fragrant plants.
Quick Reference
What NPK Ratio is Best for Lavender?
The recommended NPK ratio for lavender is 5-10-5. The phosphorus-heavy 5-10-5 ratio supports strong root systems and flower/fruit production in lavender.
Lavender NPK needs shift at each growth stage. Mild balanced feed only at initial planting during the Seedling phase, then minimal or no feeding during bloom; lean soil intensifies fragrance once flowering begins.
NPK by Growth Stage for Lavender
| Growth Stage | NPK Ratio | Notes |
|---|---|---|
| Seedling | 10N 10P 10K N 10% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Mild balanced feed only at initial planting |
| Vegetative | 5N 10P 5K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 5% Potassium: health and disease resistance Learn more about NPK | Very light feeding in spring for established plants |
| Flowering | 0N 10P 10K N 0% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Minimal or no feeding during bloom; lean soil intensifies fragrance |
| Fruiting | 0N 0P 0K N 0% Nitrogen: leaf and stem growth P 0% Phosphorus: roots and flowers K 0% Potassium: health and disease resistance Learn more about NPK | No feeding after flowering; allow plants to harden for winter |
When Should You Fertilize Lavender?
In zone 5, start fertilizing lavender in May. In zone 10, begin as early as February. Apply every 12 weeks through the growing season.
Which Zones Can Grow Lavender?
Lavender grows in USDA zones 5 through 10, spanning a 6-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 5 | May |
| Zone 6 | April |
| Zone 7 | April |
| Zone 8 | March |
| Zone 9 | March |
| Zone 10 | February |
What Are the Best Fertilizer Products for Lavender?
Look for products with an NPK close to 5-10-5. Espoma Flower-tone is the most popular choice among home gardeners for lavender.
- Espoma Flower-tone
- Dr. Earth Flower Girl
- Osmocote Flower & Vegetable
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Lavender
Container lavender needs minimal feeding; once in spring with slow-release granules is sufficient for the entire season
Common Fertilizing Mistakes with Lavender
- Over-fertilizing causes soft, leggy growth that winter-kills easily
- Rich, moist soil causes root rot; lavender needs lean, well-drained conditions
- Using acidic fertilizer lowers pH below lavender's preferred alkaline range
Tips for Fertilizing Lavender
- Add lime or crushed oyster shells to maintain alkaline pH (6.5-8.0)
- A single light application of slow-release fertilizer in early spring is all that is needed
- Excellent drainage is far more important than fertilizer for lavender success
Organic Fertilizer Alternatives for Lavender
Sources
Source:Iowa State University Extension - Growing LavenderLast updated: