Fertilizer for Calathea: NPK Guide and Application Rates
Calatheas (now reclassified under Goeppertia) are tropical houseplants known for their ornately patterned leaves that fold up at night. They are notoriously finicky about water quality, humidity, and fertilizer. Over-fertilizing and fluoride exposure are common causes of the brown leaf edges and tips that calathea owners frequently encounter.
Quick Reference
What NPK Ratio is Best for Calathea?
The recommended NPK ratio for calathea is 10-10-10. A balanced 10-10-10 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Calathea NPK needs shift at each growth stage. Gentle balanced feed for young or divided calathea during the Seedling phase, then some species flower indoors; no special feed needed once flowering begins.
NPK by Growth Stage for Calathea
| 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 | Gentle balanced feed for young or divided calathea |
| 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 formula at quarter to half strength for patterned foliage |
| Flowering | 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 | Some species flower indoors; no special feed needed |
| Fruiting | 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 | N/A for houseplant use |
When Should You Fertilize Calathea?
Fertilize calathea during the active growing season, typically April, May, June, July, August, September. Reduce or stop feeding during fall and winter when growth slows.
Apply quarter-strength balanced liquid fertilizer every 4 weeks during the active season. Always check soil moisture before feeding.
What Light Does Calathea Need?
Calathea thrives in medium light. Low light slows growth and reduces nutrient uptake, which means less fertilizer is needed in dim spots.
How Often Should You Water Calathea?
Keep soil consistently moist but not waterlogged. Soggy soil blocks oxygen from reaching roots and locks out nutrients, so proper watering directly affects how well calathea absorbs fertilizer.
Signs of Over-Fertilization in Calathea
- Leaf edges turning brown and crispy
- Leaves curling inward
- Root burn causing overall wilting
Signs of Under-Fertilization in Calathea
- Faded leaf patterns and markings
- Slower leaf unfurling
- Reduced leaf movement (prayer movement)
What Are the Best Fertilizer Products for Calathea?
Look for products with an NPK close to 10-10-10. Miracle-Gro Indoor Plant Food is the most popular choice among home gardeners for calathea.
- Miracle-Gro Indoor Plant Food
- Espoma Organic Indoor Plant Food
- Schultz All Purpose Liquid
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Calathea
Use liquid fertilizer at quarter strength monthly; calathea are extremely sensitive to fertilizer buildup and fluoride
Common Fertilizing Mistakes with Calathea
- Using full-strength fertilizer on these extremely sensitive plants
- Not using filtered water, allowing fluoride and minerals to damage roots alongside fertilizer salts
- Over-fertilizing to fix brown leaf edges that are caused by low humidity or water quality
- Not flushing accumulated fertilizer salts from the soil regularly
- Fertilizing a stressed plant that needs humidity and water quality fixes first
Tips for Fertilizing Calathea
- Feed at quarter strength monthly to avoid overwhelming sensitive roots
- Use distilled or rain water to prevent fluoride and mineral damage
- High humidity (50%+) is more important than fertilizer for healthy leaves
- Flush soil with plain water every month to prevent salt accumulation
- Calatheas prefer lower light; adjust fertilizer frequency accordingly
Organic Fertilizer Alternatives for Calathea
Sources
Source:University of Minnesota ExtensionLast updated: