Calcium Nitrate Fertilizer 15.5-0-0 (Ammonia Calcium Nitrate 15.5-0-0)
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- $ 24.99
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- $ 24.99
- Regular Price
- $ 19.99
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Calcium Nitrate Fertilizer 15.5-0-0
Premium ammonium calcium nitrate with 15.5% nitrogen and 19% calcium. Fast-acting, 100% water-soluble formula prevents blossom end rot, strengthens cell walls, and delivers dual nutrients efficiently. Perfect for tomatoes, peppers, and all calcium-hungry crops in soil or hydroponic systems.
✓Made in USA
🏆Since 1989
📦Free Shipping $100+
♻️Eco-Friendly
Quick Links:
Prevent Blossom End Rot Timeline
Week 1
🌱
First Flowers
Week 2
🍅
Walnut-Sized
Week 3-4
✓
Protected
Harvest
🎯
Perfect Fruits
Perfect For These Applications
Tomatoes & Peppers
3-4 lb/100 sq ft
Cucurbits
Zucchini, Cucumbers, Melons
Leafy Greens
Prevents tip burn
Brassicas
Cabbage, Broccoli
Tree Fruits
Prevents bitter pit
Hydroponics
1-2 tsp/gallon
Container Plants
All potted crops
Foliar Spray
1-2 tbsp/gallon
Common Garden Problems? We've Got Solutions
😟 Blossom end rot ruining tomatoes?
✅ 19% calcium prevents and corrects deficiencies
😟 Weak stems and poor structure?
✅ Calcium strengthens cell walls for sturdy plants
😟 Slow growth and pale leaves?
✅ 15.5% nitrogen promotes vigorous green growth
😟 Poor nutrient uptake?
✅ Enhances absorption of K, Mg, and other nutrients
🛡️ 19% Calcium
Essential for cell wall strength, prevents blossom end rot and tip burn
⚡ 15.5% Nitrogen
Fast-acting nitrate and ammonium nitrogen for immediate and sustained growth
💧 100% Soluble
Completely dissolves for soil, hydroponic, and foliar applications
⚖️ pH Neutral
Delivers essential calcium without raising soil pH like lime or causing acidification like ammonium sulfate. Perfect for maintaining optimized soil conditions.
⚠️ Blossom End Rot Prevention Guide
❌
Without Calcium
Dark, sunken spots on fruit bottoms
40-60% crop loss potential
40-60% crop loss potential
✅
With Calcium Nitrate
Firm, healthy fruits throughout
Maximum marketable yield
Maximum marketable yield
⚠️ Important Application Guidelines
- Never mix directly with phosphate fertilizers (will precipitate)
- Apply when fruits are walnut-sized for best results
- Water thoroughly after soil application
- For foliar spray, apply early morning or evening
- Store in cool, dry place away from moisture
⚠️ Critical Compatibility Alert
NEVER mix Calcium Nitrate directly with phosphate fertilizers (MAP, DAP, or any phosphorus solutions) in concentrated form. This causes immediate precipitation (solid crystals forming) and makes both nutrients unavailable to plants.
In hydroponics: Add calcium nitrate and phosphate sources separately to your reservoir. Never combine them in stock tanks or concentrated solutions.
Why it matters: Calcium and phosphate react to form insoluble calcium phosphate, wasting your investment and potentially clogging irrigation systems.
Quick Dosage Guide
Select an application type above
≈2 cups per pound | Metric users: Use the interactive calculator below for precise conversions
Features & Quality Guarantee
- High Nitrogen: 15.5% combined nitrate and ammonium nitrogen
- Calcium Rich: 19% calcium for strong cell walls
- 100% Water Soluble: Solution-grade for all applications
- Phosphorus-Free: Ideal where P runoff is a concern
- pH Neutral: Won't acidify soil like ammonium sulfate
- Versatile Use: Soil, hydroponic, aeroponic, and foliar
- Professional Grade: Used by commercial growers worldwide
- CDFA Registered: California Department of Food & Agriculture
- Made in USA: Manufactured in California since 1989
- Heavy Metal Free: Third-party tested for purity
- 90-Day Guarantee: Full refund if not satisfied
- Eco-Friendly: Biodegradable packaging materials
Application Rates & Timing
Mix into topsoil or dissolve in water. Always water thoroughly after application.
📅 Seasonal Application Guide
Spring
Apply at planting & first flowers
Summer
Critical when fruits form
Fall
Continue for late crops
Winter
Greenhouse applications
🍅 Tomatoes & Peppers
| Stage | Rate | Frequency |
|---|---|---|
| At Planting | 1-2 lb/100 sq ft | Once |
| First Fruit Set | 2-3 lb/100 sq ft | Once |
| Maintenance | 1 lb/100 sq ft | Every 2-3 weeks |
🥬 Leafy Vegetables
| Type | Per Plant | Per 100 sq ft |
|---|---|---|
| Lettuce | 1 tbsp | 2-3 lb |
| Cabbage | 2 tbsp | 3-4 lb |
| Spinach | 1 tsp | 2 lb |
💧 Hydroponic Systems
| System | Rate | EC Contribution |
|---|---|---|
| NFT/DWC | 1-2 tsp/gal | 0.5-1.0 mS/cm |
| Ebb & Flow | 1.5 tsp/gal | 0.75 mS/cm |
| Drip/DTW | 1 tsp/gal | 0.5 mS/cm |
🍃 Foliar Application
| Crop | Rate | Coverage |
|---|---|---|
| Tomatoes | 1-2 tbsp/gal | 100-200 sq ft |
| Fruit Trees | 2 tbsp/gal | 5-10 trees |
| Vegetables | 1 tbsp/gal | 200 sq ft |
Interactive Calculator
Compare With Other Calcium Sources
| Feature | Calcium Nitrate | Gypsum | Lime |
|---|---|---|---|
| Calcium % | 19% | 23% | 32% |
| Nitrogen % | 15.5% | 0% | 0% |
| Water Solubility | 100% | Low | Very Low |
| Speed of Action | Immediate | Slow | Very Slow |
| pH Effect | Neutral | Neutral | Raises pH |
| Best For | Quick correction + growth | Clay soils | Acidic soils |
Quick Reference Guide
📋 Application Quick Reference
Tomatoes:
3-4 lb/100 sq ft
At walnut-sized fruit
3-4 lb/100 sq ft
At walnut-sized fruit
Vegetables:
1-2 tbsp/sq ft
Every 4-6 weeks
1-2 tbsp/sq ft
Every 4-6 weeks
Hydroponics:
1-2 tsp/gallon
EC 0.5-1.0 mS/cm
1-2 tsp/gallon
EC 0.5-1.0 mS/cm
Foliar:
1-2 tbsp/gallon
Weekly during stress
1-2 tbsp/gallon
Weekly during stress
Documents & Resources
Frequently Asked Questions
What is calcium nitrate?
Calcium nitrate provides nitrogen (15.5%) as nitrate and ammonium forms, plus calcium (19%) as Ca²⁺. It dissolves completely for immediate availability. Essential for preventing blossom end rot and strengthening cell walls.
Does it prevent blossom end rot?
Yes! The 19% calcium content effectively prevents blossom end rot in tomatoes, peppers, and squash. Apply when fruits are walnut-sized for best results. Continue applications every 2 weeks during fruit development.
When should I apply it?
Apply at planting, then again when fruits are walnut-sized. This is the critical period when calcium demand is highest. Also apply after heavy rain or during drought stress when calcium uptake is impaired.
Can I use it in hydroponics?
Yes! Use 1-2 tsp per gallon for EC contribution of 0.5-1.0 mS/cm. Never mix directly with phosphate solutions - add separately. Ideal for NFT, DWC, and ebb & flow systems.
How does it compare to gypsum?
Unlike gypsum, calcium nitrate provides immediately available calcium AND nitrogen. It works faster and is ideal for rapid correction. Gypsum is better for clay soils, while calcium nitrate excels in all growing media.
Will it prevent blossom end rot in cucumbers and squash?
Yes! Calcium nitrate is highly effective for all cucurbits including cucumbers, zucchini, squash, and melons. Apply 2-3 lb per 100 sq ft at planting and when fruits begin forming. The fast-acting calcium prevents the characteristic brown, sunken spots.
Does it help with tip burn in lettuce and cabbage?
Absolutely. Tip burn in leafy greens and brassicas is often caused by calcium deficiency. Apply 1.5-2 lb per 100 sq ft for lettuce, or 3-4 lb per 100 sq ft for cabbage and broccoli. The nitrate nitrogen also promotes vigorous leaf growth.
Can it prevent bitter pit in apples?
Yes, calcium nitrate is commonly used in orchards to prevent bitter pit in apples and pears. Apply as a foliar spray at 2 tbsp per gallon, starting at petal fall and continuing every 2-3 weeks through fruit development. This ensures adequate calcium reaches developing fruit.
What about mixing with other fertilizers?
Never mix directly with phosphate solutions - add separately to avoid precipitation. Compatible with most other nutrients when dissolved in water. In hydroponics, always add calcium nitrate to the reservoir first, then add phosphates from the opposite end.
Have Questions?
Important: This product is intended for agricultural and horticultural use only. Follow all label directions. Keep out of reach of children. Store in a cool, dry place.
