• Wear chemical-resistant gloves when handling dry granules or concentrated solutions
• Wear safety glasses or goggles to prevent eye contact with dust
• Use a dust mask or N95 respirator when handling large quantities in enclosed spaces
• Wash hands and exposed skin thoroughly after handling

• Store in a cool, dry place in the original sealed container
• Calcium nitrate is hygroscopic — absorbs moisture from air. Reseal bags tightly after each use
• Keep away from direct sunlight and heat sources
• Store separately from phosphate fertilizers and organic materials
• Keep out of reach of children and pets

• Never mix directly with phosphate fertilizers (MAP, DAP, MKP) — causes immediate precipitation
• In hydroponics: add calcium nitrate to the reservoir FIRST, then add phosphates separately
• For foliar spray, apply when temperatures are below 85°F to avoid leaf burn
• Water soil thoroughly after dry application to prevent salt buildup on roots
• Do not apply to wilted or drought-stressed plants — water first, then fertilize

• Eye contact: Flush with clean water for 15 minutes. Remove contact lenses if present. Seek medical attention if irritation persists
• Skin contact: Wash affected area with soap and water. Remove contaminated clothing
• Ingestion: Do not induce vomiting. Rinse mouth with water. Contact Poison Control (1-800-222-1222) or seek medical attention
• Inhalation: Move to fresh air immediately. Seek medical attention if coughing or difficulty breathing persists

Refer to the Safety Data Sheet (SDS) for complete safety information.

Calcium nitrate (15.5-0-0) is a water-soluble fertilizer that provides fast-acting nitrogen (as nitrate and ammonium forms) plus 19% calcium as Ca²⁺ ions. It dissolves completely for immediate plant availability and is essential for preventing blossom end rot, strengthening cell walls, and supporting vigorous growth. Learn more in our guide to choosing the right calcium fertilizer.

Yes. The 19% calcium content effectively prevents blossom end rot in tomatoes, peppers, cucumbers, squash, and melons. Apply when fruits are walnut-sized and continue every 2 weeks during fruit development. Consistent watering is equally important — inconsistent moisture disrupts calcium transport even when soil calcium is adequate.

Apply at planting for baseline nutrition, then again when fruits are walnut-sized — the critical period when calcium demand peaks. Continue maintenance applications every 2-3 weeks. Also apply after heavy rain (which leaches calcium) or during drought stress (which impairs calcium uptake).

Absolutely. Use 1-2 tsp per gallon for an EC contribution of 0.5-1.0 mS/cm. Always add calcium nitrate to the reservoir first, before phosphate sources — mixing them directly causes calcium phosphate precipitation. Works in NFT, DWC, ebb and flow, and drip systems. See our complete guide to hydroponic fertilizers.

Calcium nitrate provides immediately available calcium AND nitrogen, dissolves 100% in water, and has a neutral pH effect. Gypsum is slow-releasing and better for clay soil improvement. Lime raises soil pH and takes weeks to release calcium. For rapid deficiency correction, calcium nitrate is the clear choice.

It depends on your needs. Calcium nitrate delivers higher concentrations of both nitrogen (15.5%) and calcium (19%). Cal-Mag Plus provides lower amounts but also includes magnesium and iron — making it better for RO water, coco coir, and situations where multiple secondary nutrients are deficient. Many hydroponic growers use both: calcium nitrate as the primary calcium/nitrogen source and Cal-Mag Plus as a secondary supplement.

Never mix directly with phosphate solutions (MAP, DAP, MKP) — this causes immediate calcium phosphate precipitation. In hydroponics, add calcium nitrate to the reservoir first, then add phosphate sources from the opposite end. It's compatible with most other nutrients including potassium sulfate, Epsom salt, and micronutrient chelates when dissolved in water.

Yes. Tip burn in lettuce, cabbage, and other leafy greens is typically caused by calcium deficiency during periods of rapid growth. Apply 1.5-2 lb per 100 sq ft for lettuce, or use 1 tbsp per gallon as a foliar spray for rapid correction. The nitrate nitrogen also promotes vigorous leaf growth. For more on lettuce nutrition, see our article on the best fertilizer for lettuce.

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. Multiple applications are more effective than a single heavy application.

Calcium nitrate has a neutral pH effect — it won't acidify soil like ammonium sulfate or raise pH like lime. This makes it safe for repeated applications without requiring pH correction. In hydroponic systems, monitor pH as usual and adjust to 5.5-6.5 for optimal calcium uptake.

• CDFA Registered — California Department of Food & Agriculture
• Commercial Grade — same quality trusted by professional growers
• Made in USA — manufactured in California since 1989
• Tested for Heavy Metals — third-party laboratory verified purity
• 100% Water Soluble — solution grade for all application methods

We stand behind every product with a 90-day money-back guarantee. If you're not completely satisfied with your purchase, contact our team for a full refund — no questions asked.

Our agricultural specialists are available to answer your questions about application rates, compatibility, nutrient programs, and growing strategies. Email us anytime at questions@greenwaybiotech.com.