Fertilizer for Anthurium: NPK Guide and Application Rates
Anthuriums are tropical houseplants with glossy, heart-shaped spathes in vibrant reds, pinks, and whites. They are epiphytic in nature and have sensitive root systems that require careful, dilute feeding. A phosphorus boost during the growing season encourages more frequent and larger flower production.
Quick Reference
What NPK Ratio is Best for Anthurium?
The recommended NPK ratio for anthurium is 20-20-20. A balanced 20-20-20 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Anthurium NPK needs shift at each growth stage. Light balanced feed for young or divided plants during the Seedling phase, then high phosphorus encourages colorful spathe production once flowering begins.
NPK by Growth Stage for Anthurium
| 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 for young or divided plants |
| Vegetative | 20N 20P 20K N 20% Nitrogen: leaf and stem growth P 20% Phosphorus: roots and flowers K 20% Potassium: health and disease resistance Learn more about NPK | Balanced formula supports glossy foliage |
| Flowering | 10N 30P 20K N 10% Nitrogen: leaf and stem growth P 30% Phosphorus: roots and flowers K 20% Potassium: health and disease resistance Learn more about NPK | High phosphorus encourages colorful spathe production |
| Fruiting | 20N 20P 20K N 20% Nitrogen: leaf and stem growth P 20% Phosphorus: roots and flowers K 20% Potassium: health and disease resistance Learn more about NPK | N/A for typical houseplant use |
When Should You Fertilize Anthurium?
Fertilize anthurium during the active growing season, typically March, April, May, June, July, August, September. Reduce or stop feeding during fall and winter when growth slows.
Apply quarter-strength liquid fertilizer every 6 weeks during the active season. Always check soil moisture before feeding.
What Light Does Anthurium Need?
Anthurium thrives in bright indirect light. Low light slows growth and reduces nutrient uptake, which means less fertilizer is needed in dim spots.
How Often Should You Water Anthurium?
When top inch of soil is dry, allow slight drying between waterings. Soggy soil blocks oxygen from reaching roots and locks out nutrients, so proper watering directly affects how well anthurium absorbs fertilizer.
Signs of Over-Fertilization in Anthurium
- Flower spathes turning brown at edges
- Root tips blackening
- Leaves developing brown patches
Signs of Under-Fertilization in Anthurium
- No new flowers produced
- Flowers emerging small and pale
- Green spathes instead of red
What Are the Best Fertilizer Products for Anthurium?
Look for products with an NPK close to 20-20-20. Miracle-Gro Indoor Plant Food is the most popular choice among home gardeners for anthurium.
- Miracle-Gro Indoor Plant Food
- Jack's Classic Bloom Booster
- Espoma Organic Indoor
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Anthurium
Use liquid fertilizer at quarter strength every 6 weeks; anthurium roots are sensitive and need very dilute solutions
Common Fertilizing Mistakes with Anthurium
- Using full-strength fertilizer on these epiphytic plants with delicate roots
- Over-fertilizing in hopes of forcing bloom production
- Using heavy soil that traps fertilizer salts around sensitive roots
- Fertilizing during winter when growth slows significantly
- Neglecting light requirements while relying on fertilizer for blooms
Tips for Fertilizing Anthurium
- Feed at quarter strength every 6 weeks to protect sensitive aerial roots
- A high-phosphorus bloom booster can increase flower production
- Orchid fertilizer works well as anthuriums are also epiphytic
- Ensure good drainage in an airy, chunky potting mix alongside fertilizer
- Bright indirect light is essential for blooming regardless of fertilizer
Organic Fertilizer Alternatives for Anthurium
Sources
Source:UF/IFAS Gardening SolutionsLast updated: