Fertilizer for Basil: NPK Guide and Application Rates
Basil is a warm-season herb that responds well to moderate nitrogen feeding, which promotes the lush, aromatic leaf growth that makes it valuable in the kitchen. The key is consistent, light feeding rather than heavy, infrequent applications.
Quick Reference
What NPK Ratio is Best for Basil?
The recommended NPK ratio for basil is 10-10-10. A balanced 10-10-10 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Basil NPK needs shift at each growth stage. Light balanced feeding for seedlings during the Seedling phase, then pinch flowers and continue light feeding for leaf harvest once flowering begins.
NPK by Growth Stage for Basil
| 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 | Light balanced feeding for seedlings |
| Vegetative | 10N 5P 5K N 10% Nitrogen: leaf and stem growth P 5% Phosphorus: roots and flowers K 5% Potassium: health and disease resistance Learn more about NPK | Nitrogen-forward for lush, aromatic leaf production |
| Flowering | 5N 5P 5K N 5% Nitrogen: leaf and stem growth P 5% Phosphorus: roots and flowers K 5% Potassium: health and disease resistance Learn more about NPK | Pinch flowers and continue light feeding for leaf harvest |
| Fruiting | 5N 5P 5K N 5% Nitrogen: leaf and stem growth P 5% Phosphorus: roots and flowers K 5% Potassium: health and disease resistance Learn more about NPK | Not applicable; basil is harvested as a leaf crop |
When Should You Fertilize Basil?
In zone 4, start fertilizing basil in June. In zone 11, begin as early as January. Apply every 3 weeks through the growing season.
Which Zones Can Grow Basil?
Basil grows in USDA zones 4 through 11, spanning a 8-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 4 | June |
| Zone 5 | May |
| Zone 6 | May |
| Zone 7 | April |
| Zone 8 | March |
| Zone 9 | March |
| Zone 10 | February |
| Zone 11 | January |
What Are the Best Fertilizer Products for Basil?
Look for products with an NPK close to 10-10-10. Espoma Garden-tone is the most popular choice among home gardeners for basil.
- Espoma Garden-tone
- Neptune's Harvest Fish & Seaweed
- Fox Farm Grow Big
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Basil
Feed container basil every 2 weeks with half-strength liquid fertilizer; pinch flowers to keep plants producing leaves
Common Fertilizing Mistakes with Basil
- Allowing basil to flower causes leaves to turn bitter and production to slow
- Heavy nitrogen applications can reduce the essential oil content that gives basil its flavor
- Planting too early in cold soil stunts growth regardless of fertilizer
Tips for Fertilizing Basil
- Pinch flower buds as they appear to keep basil producing tender, flavorful leaves
- Harvest from the top down, cutting just above a leaf node to encourage branching
- Light, frequent liquid feeding produces better results than heavy granular applications
Organic Fertilizer Alternatives for Basil
Sources
Source:Purdue University ExtensionLast updated: