Cronk CalMag 2-0-0 | Calcium Magnesium Iron Supplement
500mL
$12.88
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Cronk CalMag 2-0-0 | Calcium Magnesium Iron Supplement
$12.88
NPK Ratio:
2-0-0
Product Overview
CalMag 2-0-0 is a concentrated calcium and magnesium supplement with chelated iron that prevents the most common nutrient deficiencies in modern cultivation. Essential for coco coir growers, RO water users, and LED grows where calcium and magnesium demand increases significantly beyond what base nutrients provide.
Calcium deficiency causes brown spots and weak cell walls. Magnesium deficiency causes yellowing between leaf veins. Both are widespread in coco coir (which strips Cal-Mag from solution), RO water systems (which lack natural minerals), and under LED lighting (which increases metabolic demand). CalMag prevents these issues with chelated minerals that remain plant-available across pH ranges 4.0-6.5.
Key Benefits
- Chelated calcium strengthens cell walls and supports nutrient transport
- Chelated magnesium maintains chlorophyll production and photosynthetic capacity
- EDTA-chelated iron prevents yellowing and supports energy production
- 2% nitrogen supports healthy leaf development during supplementation
When Do You Need CalMag?
- Growing in coco coir (coco binds calcium and magnesium)
- Using RO or soft water (lacks natural minerals)
- Growing under LED lighting (increases Cal-Mag demand)
- Seeing brown spots or interveinal yellowing
What's Inside
Guaranteed Analysis: 2-0-0
| Total Nitrogen (N) | 2% |
| Calcium (Ca) | 3.2% |
| Magnesium (Mg) | 1.2% |
| Iron (Fe) (Chelated) (Chelated) | 0.1% |
Derived From:
Calcium Nitrate, Magnesium Nitrate, Iron EDTA
How To Use
CalMag 2-0-0
Provides essential calcium, magnesium, iron, and nitrogen to prevent common deficiencies. Highly recommended for use with Bonnie & Clyde autoflower nutrients. Can be added to the Classic Line 3-Part system if needed. Frequency: Use with every feeding if using RO water, OR use 1-2 times per week with tap water.
- Mix in room temperature water (65-72°F / 18-22°C)
- Classic Line: Add AFTER Micro, Grow, and Bloom (if using)
- Autoflower Line: Add AFTER Bonnie or Clyde (highly recommended)
- If using RO water: Use with EVERY feeding
- If using tap water: Use 1-2 times per week
- Essential when using coco coir
- Prevents calcium and magnesium deficiencies while supporting cell structure
- For specific dosages and week-by-week schedule, see Feed Schedules section
💡 Pro Tip: Use with every feeding if using RO water. With tap water, use 1-2 times per week. Add after base nutrients, before other additives.
Basic Mixing Instructions
- Start with room temperature water (65-72°F / 18-22°C)
- If using Armadillo Armour, add it FIRST
- Add base nutrients in proper order and mix thoroughly
- Add CalMag after base nutrients (if applicable)
- Add other additives, with Monkey Juice LAST
- Check pH (5.6-6.4 depending on stage and medium)
- Apply to plants - water until 10-20% runoff
Customer Reviews
Feed Schedules & Dosage
CalMag 2-0-0 Feed Schedule
Week-by-week dosage for CalMag. Use throughout entire grow cycle with Classic or Autoflower systems.
Vegetative Stage
| Week | mL/Gallon | mL/Liter |
|---|---|---|
| Week 1 | 5.0 mL | 1.32 mL |
| Week 2 | 5.0 mL | 1.32 mL |
| Week 3 | 5.0 mL | 1.32 mL |
| Week 4 | 5.0 mL | 1.32 mL |
Flowering Stage
| Week | mL/Gallon | mL/Liter |
|---|---|---|
| Week 1 | 5.0 mL | 1.32 mL |
| Week 2 | 5.0 mL | 1.32 mL |
| Week 3 | 5.0 mL | 1.32 mL |
| Week 4 | 5.0 mL | 1.32 mL |
| Week 5 | 5.0 mL | 1.32 mL |
| Week 6 | 5.0 mL | 1.32 mL |
| Week 7 | 5.0 mL | 1.32 mL |
| Week 8 | 5.0 mL | 1.32 mL |
| Week 9 | 0.0 mL | 0.0 mL |
Compatibility
Compatible Plant Types
Hemp
Vegetables
Fruits
Flowers
Houseplants
High-Value Crops
Compatible Growing Mediums
Soil
Coco Coir
Hydroponics
Soilless Mixes
Compatible Irrigation Styles
Hand Watering
Drip Systems
AutoPot Systems
Bottom Feed
Recirculating Systems
Fertigation
General Mixing Tips
- Use room temperature water (65-72°F / 18-22°C)
- Mix each nutrient thoroughly before adding the next
- Never mix concentrated nutrients together
- Check and adjust pH after all nutrients are mixed
- Store nutrients in cool, dark place away from direct sunlight
Frequently Asked Questions
What does CalMag (2-0-0) actually do?
It supplies calcium, magnesium, iron, and a touch of nitrogen to prevent Ca/Mg/Fe deficiencies, strengthen cell walls, and support chlorophyll and photosynthesis.
When should I add CalMag in my grow?
Use it proactively with RO/soft water, coco/soilless mixes, and under high light or heavy feeding—times when plants demand extra Ca/Mg.
What’s the correct mixing order with CalMag?
Water → (if using) Armadillo Armour → CalMag → Micro → Grow → Bloom → additives → Monkey Juice → pH adjust last. Add one product at a time and stir between each.
Is CalMag compatible with my nutrient line and system?
Yes—works with all Cronk bases (Classic 3-Part, Bonnie & Clyde, PuurOrganics) and in soil, coco, hydro, and drip systems when used as directed.
Can I use CalMag as a foliar spray?
Yes—apply per label at lights-off/early morning and test on a small area first; avoid spraying open flowers.
Will CalMag help fruiting vegetables and garden crops?
Definitely—great for tomatoes, peppers, strawberries, and cucurbits to reduce blossom-end issues and support steady fruit fill.
Is CalMag good for houseplants?
Yes—use light doses on foliage plants like monstera and fiddle-leaf fig to maintain leaf color and prevent tip burn; feed every 2–4 weeks and water plain between.
How do I spot Ca/Mg/Fe problems—and what’s the fix?
Look for weak stems, interveinal chlorosis, rusty leaf edges, or pale new growth. Add CalMag at label rate, keep pH in range, and adjust gradually based on plant response.
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Legal Disclaimer
Important Information for Our Customers
At Cronk Nutrients, we are committed to providing high-quality liquid plant fertilizers suitable for a variety of horticultural applications. Our products are designed for legal and responsible use by home growers and gardening enthusiasts. We do not condone or promote the use of our products for illegal purposes.
Customers are responsible for adhering to their local and state laws regarding plant cultivation. It is the sole responsibility of the customer to ensure compliance with all applicable laws and regulations. Cronk Nutrients will not be liable for any misuse of our products in violation of any laws.
By purchasing our products, the customer acknowledges their obligation to comply with the legal standards set forth in their jurisdiction and agrees to use our products in accordance with these laws. Cronk Nutrients reserves the right to refuse service to anyone suspected of using our products for illegal cultivation.
Thank you for choosing Cronk Nutrients for your plant nutrition needs. Grow with confidence, grow legally.