Cronk PuurCalMag | Organic Cal-Mag Plant Supplement
500mL
$14.88
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Cronk PuurCalMag | Organic Cal-Mag Plant Supplement
$14.88
NPK Ratio:
N/A
Product Line
Additives & Boosters
Application Stage
All Stages
Growing Medium
Soil, Coco, Living Soil
Certification
OMRI Listed
Product Overview
PuurCalMag is an OMRI-certified organic calcium and magnesium supplement chelated with organic acetic acid for fast absorption. The formula prevents the most common nutrient deficiencies in coco coir, RO water systems, and LED grows while maintaining full organic compliance. Essential for any PuurOrganics feeding program.
Calcium and magnesium deficiencies plague organic growers using modern cultivation methods. Coco coir strips calcium from nutrient solutions. RO water lacks natural mineral content. LED lighting increases Cal-Mag demand. PuurCalMag solves these problems with organically chelated minerals that remain plant-available across all pH ranges.
Key Benefits
- Organic acetic acid chelation delivers fast calcium and magnesium absorption
- Prevents brown spots, interveinal yellowing, and weak cell walls
- Sourced from mined limestone (calcium) and deep-earth brine (magnesium)
- OMRI Listed for certified organic production
Ideal For
Organic growers using coco coir, RO water, or LED lighting where calcium and magnesium deficiencies commonly occur. Apply at every feeding from seedling through harvest.
Best Results In
Soil, living soil, and coco coir. While fully soluble and technically hydro-compatible, organic nutrients in DWC/RDWC require more attention to reservoir management and pH stability. New hydro growers should consider the Classic 3-Part system.
What's Inside
Guaranteed Analysis
| Calcium (Ca) | 4.0% |
| Magnesium (Mg) | 1.65% |
Derived From:
Calcium Carbonate, Magnesium Chloride
How To Use
PuurCalMag
Part of the 5-Part PuurOrganic system. Provides organic calcium from limestone and magnesium from deep-earth brine to prevent deficiencies and support cell structure. All 5 PuurOrganic products are recommended to be used together for best results. Frequency: Use with every feeding or every other feeding. In coco, feed with every watering.
- Mix in room temperature water (65-72°F / 18-22°C)
- PuurOrganic Mixing Order: PuurNitro → PuurPhos → PuurK → PuurCalMag (4th) → PuurBalance
- Frequency: Use with every feeding or every other feeding. In coco, feed with every watering.
- Gradually increase from seedling to peak during late veg and mid flower
- Taper down during late flower before flush
- Essential when using RO water, coco coir.
- For specific dosages and week-by-week schedule, see Feed Schedules section
💡 PuurOrganic Mixing: Armadillo (if using) → PuurNitro → PuurPhos → PuurK → PuurCalMag (4th) → PuurBalance → Additives → Monkey Juice (LAST)
Best Results In
Soil, living soil, and coco coir. While fully soluble and technically hydro-compatible, organic nutrients in DWC/RDWC require more attention to reservoir management and pH stability. New hydro growers should consider the Classic 3-Part system.
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
Cronk PuurCalMag | Organic Cal-Mag Plant Supplement Feed Schedule
Detailed week-by-week feed schedule available. Part of the 5-Part PuurOrganic system.
OMRI Certified Organic. Use alongside other PuurOrganic products for complete nutrition.
Compatibility
Compatible Plant Types
Hemp
Vegetables
Fruits
Flowers
Houseplants
High-Value Crops
Compatible Growing Mediums
Soil
Coco Coir
Hydroponics
Living Soil
Soilless Mixes
Compatible Irrigation Styles
Hand Watering
Drip Systems
AutoPot Systems
Bottom Feed *
Recirculating Systems
Fertigation
* Bottom Feed Notice: PuurOrganic nutrients may create a biofilm buildup in bottom-feed reservoirs. Regular cleaning is recommended when using bottom-feed systems.
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
When should I add PuurCalMag?
Use it proactively with RO/soft water, coco/soilless mixes, and under high-intensity lighting—situations where plants demand more calcium and magnesium.
What is PuurCalMag and why use it?
It’s a clean, fully soluble organic calcium and magnesium supplement that prevents common Ca/Mg issues, strengthens stems, and supports steady growth in veg and bloom.
Where does PuurCalMag go in my mixing order?
PuurOrganics: PuurNitro → PuurPhos → PuurK → PuurCalMag → PuurBalance. Mineral bases (Micro/Grow/Bloom or Bonnie/Clyde): (if using) Armadillo Armour → PuurCalMag → base nutrients → additives; microbes last; pH last.
Can I use PuurCalMag with other nutrient lines and additives?
Yes—compatible with any nutrient base (PuurOrganics, Classic 3-Part, Bonnie & Clyde) and all Cronk additives. Add silica first, carbs after bases, and microbes (Monkey Juice) last.
Is it safe for hydro, drip, and AutoPot systems?
Yes—fully soluble and line-safe. For single-reservoir AutoPot setups, use a small mixing pump/airstone; the tank won’t film, but pot inlets/trays can—run ½-strength and flush/clean inlets weekly.
Can I foliar spray PuurCalMag?
Yes—apply a fine mist at lights-off or early morning, focusing on leaf undersides. Start at a low rate and test on a small area before broad use.
Will it affect pH or EC?
It will raise EC slightly; always adjust pH after mixing your full solution. Typical targets: soil 6.2–6.8, coco/hydro 5.8–6.2.
Complete Your System
Add these essential products for optimal results throughout your grow.
8-0-0
PuurNitro 8-0-0: Organic N
OMRI Listed organic nitrogen for explosive veg growth.
- OMRI Listed organic nitrogen
- Derived from soybean protein
- Vegetative growth booster
From $21.88
0-12-0
PuurPhos 0-12-0: Organic P
OMRI Listed organic phosphorus for bloom and root development.
- OMRI Listed organic phosphorus
- Derived from pumpkin seeds
- Flowering stage booster
From $17.88
0-0-15
PuurK 0-0-15: Organic K
OMRI Listed organic potassium for stronger stems and flowers.
- OMRI Listed organic potassium
- Derived from durian shells
- Strengthens stems and flowers
From $18.88
Complete Kit
Save 5%
Save with the Complete Kit
Get everything you need in one package and save up to 15%.
PuurOrganics Complete Kit
Ideal for growers seeking a complete organic solution that delivers clean, balanced nutrition from seed to harvest.
- All-in-one organic system
- Promotes fast, balanced growth
- Maximizes quality and yield — no synthetics
$97.40
$92.53
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.