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Calcium Nitrate Fertilizer 15.5-0-0 (Ammonia Calcium Nitrate 15.5-0-0)

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$ 19.99
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$ 19.99
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$ 19.99
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Weight: 2 Pounds

Calcium Nitrate Fertilizer 15.5-0-0 + 19% Ca | Greenway Biotech®

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 $35+
♻️Eco-Friendly

Prevent Blossom End Rot Timeline

Week 1🌱First Flowers
Week 2🍅Walnut-Sized
Week 3-4Protected
Harvest🎯Perfect Fruits

Perfect For These Applications

🍅
Tomatoes
3-4 lb/100 sq ft
🥬
Vegetables
1-2 tbsp/sq ft
💧
Hydroponics
1-2 tsp/gallon
🍃
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

⚠️ Blossom End Rot Prevention Guide

Without Calcium
Dark, sunken spots on fruit bottoms
40-60% crop loss potential
With Calcium Nitrate
Firm, healthy fruits throughout
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

Quick Dosage Guide

Select an application type above
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

Apply when fruits are walnut-sized
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

Prevents tip burn in lettuce
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

Maintain EC 1.5-2.5 mS/cm
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

Spray early morning or evening
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
FERTILIZER CALCULATOR

Calcium Nitrate Calculator

Calculate exact amounts for preventing blossom end rot

Tomato & Pepper Application

📋 Recommended: 3-4 lb per 100 sq ft at fruit set

Vegetable Garden

📋 General rate: 1-2 tbsp per square foot

Hydroponic Systems

📋 Mix 1-2 tsp per gallon for EC 0.5-1.0 mS/cm

Foliar Spray

📋 Mix 1-2 tbsp per gallon for foliar application

Cost Comparison

📋 Compare calcium nitrate vs. other calcium sources

COMPARE WITH OTHER CALCIUM SOURCES
Calcium Source Comparison
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
Vegetables:
1-2 tbsp/sq ft
Every 4-6 weeks
Hydroponics:
1-2 tsp/gallon
EC 0.5-1.0 mS/cm
Foliar:
1-2 tbsp/gallon
Weekly during stress
DOCUMENTS
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.
HAVE QUESTIONS?
Call: (562) 351-5168
Email: questions@greenwaybiotech.com
Hours: Mon-Fri 8AM-5PM PST

Greenway Biotech, Inc. | Est. 1989 | Premium fertilizers made in California, USA

Customer Reviews

Based on 63 reviews
89%
(56)
3%
(2)
5%
(3)
0%
(0)
3%
(2)
R
Robert Findlay
bag spilt

Bag came in with a split in a seam. Sent in photos of split, pellets in box and spilling out of box into kitchen. Not a word back... guess greenway doesn't give a s**t

C
Charlie Bauerelen
Happy gardener

Very easy little goes long way

J
John Gjovik
Great product

First time using Calcium Nitrate in conjunction with 4-18-38 tomato fertilizer in my NFT system and all the varieties of micro dwarf tomatoes are loving it. Also used in raised beds and potted plants with great success. Will be buying more for sure.

C
Charles Snow
Very Powerful

I recommend only one application on Tomato plants when Blossoms start to appear. One application per season! One teaspoon mixed with two gallons on water.

G
Gary Hennessey
Effect of Calcium Nitrate

Explosive tomato/pepper plants. Used as a dissolved addition. Great way to provide calcium and nitrogen simultaneously while not destroying the bacteria in the soil. I use it on all veg garden plants.