Fertilizer for Stevia: NPK Guide and Application Rates
Stevia is a subtropical perennial herb grown for its intensely sweet leaves, which can be 200-300 times sweeter than sugar. Purdue University Extension notes that stevia is a moderate feeder that produces the sweetest leaves when grown in well-drained, fertile soil with consistent moisture. In most of North America (zones 3-7), stevia is grown as an annual or container plant, as it is killed by temperatures below 28 degrees F.
Quick Reference
What NPK Ratio is Best for Stevia?
The recommended NPK ratio for stevia is 10-10-10. A balanced 10-10-10 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Stevia NPK needs shift at each growth stage. Balanced formula for transplants after last frost during the Seedling phase, then reduce nitrogen; pinch flowers to maintain leaf production once flowering begins.
NPK by Growth Stage for Stevia
| 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 transplants after last frost |
| Vegetative | 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 feeding promotes leaf production |
| Flowering | 5N 10P 10K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Reduce nitrogen; pinch flowers to maintain leaf production |
| Fruiting | 5N 10P 10K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Harvest all leaves before first frost |
When Should You Fertilize Stevia?
In zone 8, start fertilizing stevia in April. In zone 11, begin as early as February. Apply every 4 weeks through the growing season.
Which Zones Can Grow Stevia?
Stevia 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 | March |
| Zone 11 | February |
What Are the Best Fertilizer Products for Stevia?
Look for products with an NPK close to 10-10-10. Espoma Plant-tone is the most popular choice among home gardeners for stevia.
- Espoma Plant-tone
- Dr. Earth Herb
- 10-10-10 organic
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Stevia
Ideal container herb in cold climates; feed every 3 weeks with balanced liquid organic fertilizer
Common Fertilizing Mistakes with Stevia
- Allowing stevia to flower, which reduces leaf sweetness and signals the plant to shut down.
- Over-fertilizing with nitrogen, which produces large but less sweet leaves.
- Starting stevia from seed, which has very low germination rates; buy transplants instead.
- Leaving container stevia outdoors after the first light frost, which kills the plant.
Tips for Fertilizing Stevia
- Feed monthly with balanced organic fertilizer during the growing season for maximum leaf production.
- Pinch flower buds to redirect energy to leaf growth; flowers signal the plant to stop producing leaves.
- Harvest all leaves before the first frost; dry them for year-round natural sweetener use.
- In cold climates, grow in containers and bring indoors before frost for overwintering.
Organic Fertilizer Alternatives for Stevia
Sources
Source:Purdue University ExtensionLast updated: