Fertilizer for Lemongrass: NPK Guide and Application Rates
Lemongrass is a tropical grass that requires heavy nitrogen feeding to produce the thick, aromatic stalks used in cooking. The University of Florida IFAS Extension recommends treating lemongrass more like a lawn grass than a traditional herb, with regular nitrogen applications throughout the growing season. In northern climates (zones 3-7), lemongrass is grown as an annual or container plant brought indoors for winter, where it needs reduced but continued feeding.
Quick Reference
What NPK Ratio is Best for Lemongrass?
The recommended NPK ratio for lemongrass is 6-4-0. The nitrogen-forward 6-4-0 ratio drives leaf and stem development, which lemongrass need for photosynthesis and canopy growth.
Lemongrass NPK needs shift at each growth stage. Balanced formula for transplant establishment during the Seedling phase, then lemongrass rarely flowers in cultivation once flowering begins.
NPK by Growth Stage for Lemongrass
| 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 | Balanced formula for transplant establishment |
| Vegetative | 6N 4P 0K N 6% Nitrogen: leaf and stem growth P 4% Phosphorus: roots and flowers K 0% Potassium: health and disease resistance Learn more about NPK | Nitrogen-forward for rapid leaf blade production |
| Flowering | 6N 4P 0K N 6% Nitrogen: leaf and stem growth P 4% Phosphorus: roots and flowers K 0% Potassium: health and disease resistance Learn more about NPK | Lemongrass rarely flowers in cultivation |
| Fruiting | 6N 4P 0K N 6% Nitrogen: leaf and stem growth P 4% Phosphorus: roots and flowers K 0% Potassium: health and disease resistance Learn more about NPK | Continue nitrogen emphasis through growing season |
When Should You Fertilize Lemongrass?
In zone 8, start fertilizing lemongrass in April. In zone 11, begin as early as February. Apply every 4 weeks through the growing season.
Which Zones Can Grow Lemongrass?
Lemongrass grows in USDA zones 8 through 11, spanning a 4-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 8 | April |
| Zone 9 | March |
| Zone 10 | February |
| Zone 11 | February |
What Are the Best Fertilizer Products for Lemongrass?
Look for products with an NPK close to 6-4-0. Espoma Plant-tone is the most popular choice among home gardeners for lemongrass.
- Espoma Plant-tone
- Blood meal
- Lawn fertilizer (nitrogen-heavy)
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Lemongrass
Popular container herb in cold climates; feed monthly with nitrogen-rich liquid fertilizer during growing season
Common Fertilizing Mistakes with Lemongrass
- Under-fertilizing; lemongrass needs far more nitrogen than typical culinary herbs.
- Leaving lemongrass outdoors in zones 7 and below, where freezing kills the crown.
- Growing in too small a container; lemongrass clumps expand rapidly and need at least 5-gallon pots.
- Harvesting the inner core of the plant, which kills the growing point.
Tips for Fertilizing Lemongrass
- Feed monthly with nitrogen-rich fertilizer during the growing season for thick, harvestable stalks.
- Lemongrass is a tropical grass; treat it like a lawn in terms of nitrogen demand.
- In cold climates, bring container lemongrass indoors before first frost and reduce feeding to bimonthly.
- Harvest outer stalks by cutting at soil level; inner stalks will continue to grow.
Organic Fertilizer Alternatives for Lemongrass
Sources
Source:UF/IFAS Gardening SolutionsLast updated: