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Emerald Harvest Cal - Mag - Green Thumb Depot
Emerald Harvest Cal-Mag

Emerald Harvest Cal-Mag

See more by Emerald Harvest
SKU: EMHCMQ

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$16.95
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Emerald Harvest Cal-Mag

Emerald Harvest Cal-Mag is a premium calcium and magnesium supplement designed to keep plants green, healthy, and productive in any growing medium. By promoting chlorophyll production, activating nutrient-uptake enzymes, and preventing deficiencies, this formula ensures robust growth, abundant flowering, and high yields. Kelp extract adds natural micronutrients, making it ideal for coco coir, soil, or hydroponic systems where extra Ca and Mg are needed.

  • Features & Benefits
  • Product Specifications
  • What is included?
  • Warranty Policy

Key Features of Emerald Harvest Cal-Mag

Emerald Harvest Cal-Mag provides essential calcium and magnesium while supporting overall plant health and nutrient absorption. Its premium ingredients and kelp extract help prevent deficiencies and maintain strong, vigorous crops for maximum yield potential.

  • Supplemental calcium and magnesium for all growing media.
  • Promotes chlorophyll production for healthy, green plants.
  • Activates plant enzymes to improve nutrient uptake.
  • Includes kelp extract for natural micronutrients and plant support.
  • Reduces the risk of calcium or magnesium deficiencies.
  • Supports strong roots, stems, and abundant flowering.

Stronger Plants, Greener Gardens

Emerald Harvest Cal-Mag ensures your crops receive the essential calcium and magnesium needed for strong cell walls, efficient nutrient absorption, and vibrant growth. Its kelp-enhanced formula supports plant metabolism, helping growers achieve lush, productive gardens and heavy harvests.

Why Emerald Harvest?

Emerald Harvest is trusted by professional growers for delivering reliable, high-quality nutrients that support every growth stage. Their 3-part nutrient system allows flexible feeding programs, precision nutrient management, and exceptional harvest results, ensuring growers achieve maximum potential and consistency in every crop.

Why Buy From Us?

At GreenThumbDepot, you're not just another sale to a faceless corporation. You're partnering with a team genuinely invested in your success. Our legendary customer service, combined with a promise of unbeatable prices, sets us apart. We're here for you, always.

Excellent 4.8 out of 5 based on 1,247 reviews
If I could rate 6 stars I would!
If I could rate 6 stars I would! My representative Edouard B. has been shockingly responsive! Like - oh my god - an actual SERVICE oriented company. He's dug into my odd connectivity issues I've been having - and following up in an AMAZINGLY timey manner. No shit. You'll be impressed! (And the price was also unbeatable, quick shipping...it's all PERFECT). Thank you Ed!!
Reviewer
Jim D

Customer service was outstanding great…
Customer service was outstanding great people to deal with they understand your needs and they will do their best to fulfill them there is no way I can complain about them because they are the best help out there.Thanks green thumb depot. I'll definitely order from them again
Reviewer
Glenn Appleton

The machine is doing just what my…
The machine is doing just what my salesman told it would do (I appreciate you Ed thank you) . The machine is what we need for our new business we're starting up, soon to be llc and licensed. We are getting a lot of clients wanting our services. Ed I will be needing more of your products, thank you again.
Reviewer
Freddie

Fantastic
Great prices, fantastic customer service, and mind blowing shipping! Incredible. Will be using again and telling anyone in need.
Reviewer
Kar

←
→

FAQ Section

What is Emerald Harvest Cal-Mag?
It is a calcium and magnesium supplement with kelp extract designed to prevent deficiencies, support chlorophyll production, and improve nutrient uptake for healthy plants.
Which sizes are available?
Emerald Harvest Cal-Mag comes in 1 qt, 1 gal, 2.5 gal, 6 gal, 15 gal, 55 gal, and 270 gal sizes.
Can I use Cal-Mag in coco coir?
Yes, it’s especially recommended for coco coir, which can have inherent calcium and magnesium deficiencies.
Does it support flowering?
Yes, by providing calcium and magnesium, it promotes strong stems and cell walls, which supports abundant flowering and fruit development.
Is it safe for hydroponic systems?
Yes, Cal-Mag is compatible with soil, coco, and hydroponic systems for consistent nutrient supplementation.
What additional nutrients are included?
In addition to calcium and magnesium, Cal-Mag contains kelp extract, providing natural micronutrients and growth-promoting compounds.
When should I apply Cal-Mag?
Apply Cal-Mag during vegetative and flowering stages as needed to prevent deficiencies or support nutrient uptake in your growing medium.

Specifications

Emerald Harvest Cal-Mag
SKU EMHCMG
NPK Nitrogen (N) 2
Dimensions (EA) 7.7L x 4.7W x 12.7H
Dimensions (CS) 13.0L x 7.9W x 18.8H
Dimensions (PL) 48.0L x 40.0W x 61.0H
Shipping Weight 10.61 lbs
Barcodes 859041005907 (UPC-A), 10859041005904 (GTIN)
Available Sizes 1 qt, 1 gal, 2.5 gal, 6 gal, 15 gal, 55 gal, 270 gal

What is included?

It includes:

  • Emerald Harvest Cal-Mag (1 qt / 1 gal / 2.5 gal / 6 gal / 15 gal / 55 gal / 270 gal)
  • User Instruction Manual

Warranty Policy

Please check out the manufcaturers website for Warranty related issues.

Emerald Harvest Cal-Mag

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Emerald Harvest Cal-Mag calcium and magnesium plant nutrient supplement

Emerald Harvest Cal-Mag

Emerald Harvest Cal-Mag is a calcium and magnesium supplement formulated for plant nutrition across soil, coco coir, hydroponic, and other soilless growing systems. The 2-0-0 formula supplies supplemental calcium and magnesium and includes kelp extract. It is designed to help reduce the risk of calcium and magnesium deficiencies, support chlorophyll production in plants, and support nutrient uptake.

For horticultural use only. Not for human or animal consumption.

Product Overview

Specifications

What's Included?

Warranty & Returns

Product Overview

Emerald Harvest Cal-Mag supplies supplemental calcium and magnesium for plant nutrition. Calcium and magnesium are important secondary nutrients used by plants for structural development, chlorophyll production, and nutrient-related processes. The formula also contains kelp extract.

Cal-Mag can be incorporated into nutrient programs used with soil, coco coir, hydroponic, and other soilless growing systems. It is particularly useful when additional calcium and magnesium supplementation is needed based on the growing medium or nutrient program.

Key Features:
1. 2-0-0 NPK formulation
2. Supplemental calcium and magnesium
3. Contains kelp extract
4. Supports chlorophyll production in plants
5. Supports plant nutrient uptake
6. Compatible with multiple growing systems

For horticultural use only. Not for human or animal consumption.

Emerald Harvest Cal-Mag nutrient supplement bottle
Emerald Harvest Cal-Mag nutrient supplement bottle

Calcium and Magnesium Support for Plant Nutrition

Emerald Harvest Cal-Mag provides supplemental calcium and magnesium for nutrient programs where additional Ca and Mg are required. The formula contains kelp extract and can be used across multiple growing media and production systems.

Plant nutrient deficiency support icon

Deficiency Support

Plant nutrient uptake icon

Nutrient Uptake

Cal-Mag nutrient formula icon

2-0-0 Formula

Plant growth support icon

Plant Growth Support

Available in Different Sizes

Application & Use

Use Emerald Harvest Cal-Mag as part of a plant nutrient program when additional calcium and magnesium supplementation is required.

1. Add Cal-Mag to water before adding base nutrients.

2. Use during vegetative and flowering stages as needed.

3. Cal-Mag can be used with soil, coco coir, hydroponic, and other soilless systems.

4. Adjust application according to the plant nutrient program and growing conditions.

5. Shake well before use.

6. Do not return unused nutrient solution to the original container.

7. Keep measuring equipment clean.

8. Store the container sealed in a cool, dry location.

Recommended application rate: 2-5 mL per gallon of water. :contentReference[oaicite:1]{index=1}

For horticultural use only. Not for human or animal consumption.

Why Emerald Harvest?

Emerald Harvest develops nutrient products for horticultural production, including base nutrients and supplemental formulas. Cal-Mag is designed to provide additional calcium and magnesium within a plant nutrient program and is available in container sizes ranging from 1 quart to 270 gallons.

Emerald Harvest brand
Emerald Harvest brand
GreenThumbDepot logo

Why Buy From GreenThumbDepot?

GreenThumbDepot provides horticultural products and growing equipment from established manufacturers. Our team helps customers compare product specifications, sizes, and application requirements so they can select products appropriate for their growing operation.

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Customer Reviews


Trusted by authentic customer reviews from verified buyers worldwide.
If I could rate 6 stars I would!
If I could rate 6 stars I would! My representative Edouard B. has been shockingly responsive! Like - oh my god - an actual SERVICE oriented company. He's dug into my odd connectivity issues I've been having - and following up in an AMAZINGLY timey manner. No shit. You'll be impressed! (And the price was also unbeatable, quick shipping...it's all PERFECT). Thank you Ed!!
Jim D
Customer service was outstanding great…
Customer service was outstanding great people to deal with they understand your needs and they will do their best to fulfill them there is no way I can complain about them because they are the best help out there.Thanks green thumb depot. I’ll definitely order from them again
Glenn Appleton
The machine is doing just what my…
The machine is doing just what my salesman told it would do (I appreciate you Ed thank you) . The machine is what we need for our new business we’re starting up, soon to be llc and licensed. We are getting a lot of clients wanting our services. Ed I will be needing more of your products, thank you again.
Freddie
Fantastic
Great prices, fantastic customer service, and mind blowing shipping! Incredible. Will be using again and telling anyone in need.
Kar
←
→


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Frequently Asked Questions

What is Emerald Harvest Cal-Mag? Expand FAQ
Emerald Harvest Cal-Mag is a 2-0-0 calcium and magnesium supplement for horticultural use. It also contains kelp extract and is designed to provide supplemental calcium and magnesium within a plant nutrient program.
Which sizes are available? Expand FAQ
Available sizes are 1 qt, 1 gal, 2.5 gal, 6 gal, 15 gal, 55 gal, and 270 gal. :contentReference[oaicite:2]{index=2}
Can Emerald Harvest Cal-Mag be used with coco coir? Expand FAQ
Yes. Emerald Harvest documentation identifies coco coir and other soilless growing media as suitable applications for Cal-Mag. :contentReference[oaicite:3]{index=3}
What does the 2-0-0 NPK designation mean? Expand FAQ
The 2-0-0 designation indicates the product's nitrogen, phosphorus, and potassium analysis. The current product specification lists Cal-Mag as 2-0-0. :contentReference[oaicite:4]{index=4}
Can Cal-Mag be used in hydroponic systems? Expand FAQ
Yes. Cal-Mag is used as a supplemental calcium and magnesium product in soil, coco coir, hydroponic, and other soilless growing systems.
Does Emerald Harvest Cal-Mag contain kelp extract? Expand FAQ
Yes. Emerald Harvest Cal-Mag contains kelp extract. :contentReference[oaicite:5]{index=5}
What is the recommended application rate? Expand FAQ
The current product information lists a recommended application rate of 2-5 mL per gallon. Follow the product label and your nutrient program for application instructions. :contentReference[oaicite:6]{index=6}
What is the 1-gallon product specification? Expand FAQ
The current GreenThumbDepot listing specifies dimensions of 7.7L x 4.7W x 12.7H inches for the 1-gallon unit and a shipping weight of 10.61 lbs. :contentReference[oaicite:7]{index=7}
Is Emerald Harvest Cal-Mag intended for human or animal consumption? Expand FAQ
No. For horticultural use only. Not for human or animal consumption.

Specs & Dimensions

Weight Weight According to selected size
Brand Brand Emerald Harvest
Size options Size Options 1 qt, 1 gal, 2.5 gal, 6 gal, 15 gal, 55 gal, 270 gal
Expand specifications
Brand Emerald Harvest
SKU EMHCMG
N-P-K 2-0-0
Dimensions (1 gal) 7.7L x 4.7W x 12.7H in.
Shipping Weight (1 gal) 10.61 lbs.
UPC (1 gal) 859041005907
GTIN (1 gal) 10859041005904
Available Sizes 1 qt, 1 gal, 2.5 gal, 6 gal, 15 gal, 55 gal, 270 gal
Formula Calcium and magnesium supplement with kelp extract

What's Included?

Emerald Harvest Cal-Mag bottle

Emerald Harvest Cal-Mag in the selected size

Product instruction manual

User Instruction Manual

For horticultural use only. Not for human or animal consumption.

Warranty & Returns

Please check the manufacturer's warranty documentation for warranty-related questions. For GreenThumbDepot return information, view our Return Policy .

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