Fertilizer for Marigolds: NPK Guide and Application Rates
Marigolds are one of the easiest annuals to grow and actually prefer lean soil over heavy fertilization. These tough, drought-tolerant flowers produce more blooms when slightly underfed than when given excessive nutrients, especially nitrogen.
Quick Reference
What NPK Ratio is Best for Marigolds?
The recommended NPK ratio for marigolds is 5-10-5. The phosphorus-heavy 5-10-5 ratio supports strong root systems and flower/fruit production in marigolds.
Marigolds NPK needs shift at each growth stage. Light balanced feed at transplanting during the Seedling phase, then phosphorus for abundant bloom production once flowering begins.
NPK by Growth Stage for Marigolds
| 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 feed at transplanting |
| 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 | Mild nitrogen for compact, branching growth |
| Flowering | 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 | Phosphorus for abundant bloom production |
| Fruiting | 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 | Continue bloom feed for season-long color |
When Should You Fertilize Marigolds?
In zone 3, start fertilizing marigolds in June. In zone 11, begin as early as January. Apply every 4 weeks through the growing season.
Which Zones Can Grow Marigolds?
Marigolds grows in USDA zones 3 through 11, spanning a 9-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 3 | June |
| Zone 4 | May |
| Zone 5 | May |
| Zone 6 | April |
| Zone 7 | April |
| Zone 8 | March |
| Zone 9 | February |
| Zone 10 | February |
| Zone 11 | January |
What Are the Best Fertilizer Products for Marigolds?
Look for products with an NPK close to 5-10-5. Espoma Flower-tone is the most popular choice among home gardeners for marigolds.
- Espoma Flower-tone
- Miracle-Gro Bloom Booster
- Osmocote Flower & Vegetable
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Marigolds
Container marigolds need only monthly feeding; they perform better slightly underfed than overfed
Common Fertilizing Mistakes with Marigolds
- Over-fertilizing with nitrogen produces large, floppy plants with few flowers
- Rich, amended soil causes marigolds to grow lush leaves at the expense of blooms
- Overhead watering rots marigold flower heads, especially African marigold types
Tips for Fertilizing Marigolds
- Deadhead regularly; marigolds bloom more prolifically when spent flowers are removed
- A single application of slow-release fertilizer at planting may be all that is needed
- Plant marigolds near tomatoes and peppers; they repel certain garden pests
Organic Fertilizer Alternatives for Marigolds
Sources
Source:Clemson University ExtensionLast updated: