SKU: 20867520996
magnesium fertilizer for plants

magnesium fertilizer for plants GS Plant Foods Cal-Mag Extreme Liquid 1 Gallon Fertilizer with Calcium, Magnesium, Iron And Sulfur Supplement, Corrects Secondary Nutrient & Trace

Sale price$21.85 Regular price$24.28
Save 10%

Pay in installments of $6.07 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 18 - Jul 23

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

magnesium fertilizer for plants GS Plant Foods Cal-Mag Extreme Liquid 1 Gallon Fertilizer with Calcium, Magnesium, Iron And Sulfur Supplement, Corrects Secondary Nutrient & TraceCal Mag Extreme GS Plant Foods Cal Mag Extreme Advanced Calcium, Magnesium & Micronutrient Supplement for Plants Strengthens Cell Walls, Prevents Deficiencies & Promotes Vigorous Growth For All Plants, Lawns & Gardens Correct Deficiencies. Strengthen Growth. Supercharge Results. GS Plant Foods Cal Mag Extreme delivers the critical secondary and micronutrients plants need for healthy, balanced growth. Formulated with highly available sources of Calcium

Cal-Mag Extreme

GS Plant Foods Cal-Mag Extreme – Advanced Calcium, Magnesium & Micronutrient Supplement for Plants – Strengthens Cell Walls, Prevents Deficiencies & Promotes Vigorous Growth – For All Plants, Lawns & Gardens

Correct Deficiencies. Strengthen Growth. Supercharge Results.

GS Plant Foods Cal-Mag Extreme delivers the critical secondary and micronutrients plants need for healthy, balanced growth. Formulated with highly available sources of Calcium and Magnesium, it also includes Sulfur, Iron, Manganese, Zinc, Boron, and Molybdenum to ensure complete nutritional support.

Calcium and magnesium are often overlooked—but they are essential for building strong cell walls, maintaining chlorophyll production, and supporting the transport of nutrients throughout the plant. Deficiencies in these elements can lead to weak stems, yellow leaves, blossom end rot, and reduced yield.

Cal-Mag Extreme prevents these problems before they start—keeping your plants strong, green, and highly productive.

 

💪 COMPLETE NUTRIENT SUPPORT: Cal-Mag Extreme provides essential Calcium (2.5%) and Magnesium (1.0%)—plus Sulfur, Iron, Manganese, Zinc, Boron, and Molybdenum—to correct deficiencies and maximize nutrient balance in your plants.

🌿 BUILDS STRONGER PLANTS: Calcium fortifies cell walls and prevents common issues like blossom end rot, while magnesium supports chlorophyll production for lush, dark-green foliage.

OPTIMIZES NUTRIENT UPTAKE: Enhances the absorption and mobility of nitrogen, phosphorus, and potassium—making your fertilizer more effective and reducing nutrient lockout.

🌸 BOOSTS GROWTH & FLOWERING: Strengthens roots, improves nutrient flow, and promotes more consistent flowering and fruiting across all plant types.

🌎 SAFE & EASY TO USE: 100% soluble and compatible with all fertilizers, hydroponic systems, and soil types. Non-toxic, environmentally safe, and suitable for all plants, indoors and outdoors.

What is Cal Mag 420 Dry?

GS Plant Foods Cal Mag 420 Dry Super Concentrate is our Dry, powdered version. Your all-in-one solution for robust plant health and unstoppable growth! This water-soluble powder delivers a powerhouse blend of calcium (13%), magnesium (3%), and sulfur (4%)—critical secondary nutrients that fortify cell walls, boost photosynthesis, and shield plants from disease. As an effective cal mag plant food for plants, it provides essential support for healthy development. With just ¼ teaspoon per gallon, one 18-ounce jar makes 420 gallons of nutrient-rich solution, perfect for soil, hydroponics, coco coir, and container gardens. 🌿

Key Benefits

💪 Stronger Plants: Natural cal mag for plants helps strengthen cell walls with calcium and boosts chlorophyll production with magnesium for lush, vibrant growth.

🛡️ Disease Defense: Cal mag fertilizer enhances natural resistance to pests, mold, and environmental stressors.

🌞 Optimized Photosynthesis: Sulfur ensures efficient nutrient mobility and energy conversion.

🌍 Universal Compatibility: Safe for all growth stages—seedling to bloom—and all growing mediums.

💧 Zero Waste: 100% water-soluble cal-mag for plants formula leaves no residue, ensuring full nutrient absorption.

Ingredient Breakdown

  • Calcium (13%): Builds robust cell structure and improves root-to-shoot nutrient flow when you add Cal-Mag for plants.

  • Magnesium (3%): Core component of chlorophyll for deeper greens and higher yields.

  • Sulfur (4%): Cal-Mag fertilizer supports enzyme production and amino acid synthesis.

  • Guaranteed Analysis: 11% nitrate nitrogen, pH-balanced for seamless integration with any regimen.

  • Derived From: Calcium nitrate and magnesium sulfate—pure, plant-ready nutrients.

What is Cal Mag 420 Dry?

GS Plant Foods Cal Mag 420 Dry Super Concentrate is our Dry, powdered version. Your all-in-one solution for robust plant health and unstoppable growth! This water-soluble powder delivers a powerhouse blend of calcium (13%), magnesium (3%), and sulfur (4%)—critical secondary nutrients that fortify cell walls, boost photosynthesis, and shield plants from disease. As an effective cal mag plant food for plants, it provides essential support for healthy development. With just ¼ teaspoon per gallon, one 18-ounce jar makes 420 gallons of nutrient-rich solution, perfect for soil, hydroponics, coco coir, and container gardens. 🌿

How to Use Cal-Mag Extreme

Simple Mix & Grow:

  1. Dilute: Stir ¼ teaspoon into 1 gallon of water (1 jar = 420 gallons!).

  2. Apply Weekly: Use as a root drench during irrigation for soil, coco, or hydroponic systems.

  3. Avoid Foliar Spray: Cal-mag fertilizer designed specifically for soil and root absorption only.

Pro Tip: Cal-Mag Extreme Liquid or Cal-Mag Dry 402 for plants pairs perfectly with primary nutrients for a complete feeding program!

Frequently Asked Questions:

Q: What is Cal-Mag Extreme?
A: balanced blend of Calcium, Magnesium, and essential micronutrients that strengthens plants, prevents deficiencies, and improves nutrient uptake. Safe and effective for all plants and growing systems.

_____________________________________________________________________________

Q: What makes Cal-Mag Extreme different from other Cal-Mag products?
A: Cal-Mag Extreme contains a complete suite of micronutrients (Fe, Mn, Zn, B, Mo) in addition to calcium and magnesium—ensuring balanced nutrition, faster uptake, and superior growth compared to basic two-element blends.


Q: How do I know if my plants need Cal-Mag?
A: If you see yellowing leaves, weak stems, blossom end rot, or poor fruit development, your plants are likely deficient in calcium or magnesium. Cal-Mag Extreme restores proper nutrient balance fast.


Q: Can I mix this with my fertilizer or kelp?
A: Absolutely. Cal-Mag Extreme is 100% compatible with all GS Plant Foods fertilizers, including Liquid Fish, Liquid Kelp, and Root Ruckus. It helps your plants make better use of those nutrients.


Q: Is this safe for edible crops and hydroponics?
A: Yes—Cal-Mag Extreme is completely soluble and safe for all growing environments, including hydroponic and aquaponic systems, greenhouses, and food crops.


Q: How often should I apply it?
A: Apply every 1–2 weeks during active growth, or whenever deficiencies are suspected. Regular use promotes steady, balanced nutrition and prevents future issues.

 

 

Applying a calcium-magnesium product can benefit various types of plants, especially those that require sufficient levels of these essential minerals for their growth and development. Calcium and magnesium are both important secondary nutrients for plants, playing vital roles in various physiological processes. Plants that can benefit from the application of a calcium-magnesium product include:

 

Tomatoes: Tomatoes require an adequate supply of calcium to prevent disorders like blossom end rot, which can affect fruit quality.

 

Peppers: Peppers benefit from balanced calcium and magnesium levels for proper fruit development and resistance to stress.

 

Cucumbers: Cucumbers also need sufficient calcium and magnesium to support healthy fruiting and prevent issues such as bitter-tasting cucumbers.

 

Leafy Greens: Plants like lettuce, spinach, kale, and other leafy greens benefit from calcium and magnesium for leaf development and overall plant vigor.

 

Broccoli and Cauliflower: These brassica vegetables can benefit from calcium and magnesium for healthy head formation and reduced susceptibility to diseases.

 

Beans: Both bush and pole beans benefit from adequate calcium and magnesium for proper pod development and overall plant growth.

 

Apples: Apple trees require calcium and magnesium for strong cell walls, which can improve fruit quality and storage ability.

 

Grapes: Grapes benefit from balanced calcium and magnesium levels for improved berry development and disease resistance.

 

Citrus Trees: Citrus trees need calcium and magnesium for healthy fruit formation and reduced susceptibility to nutrient deficiencies.

 

Potatoes: Potatoes can benefit from calcium and magnesium to prevent common issues like hollow heart and improve tuber quality.


Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 20867520996

Discover Niche Categories That Outsell magnesium fertilizer for plants

Top-Converting Item to Boost Your Average Order

4.8 ★★★★★
Based on 15 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
M
Verified Purchase
megan moyes
Los Angeles, US
★★★★★ 5
Wonderful product
Scent: Smoky coffee, Size: 4 Fl Oz (Pack of 1)
I used this on a bald spot I had and it worked extremely well. Consistency is key though it needs to be used every day
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 3, 2026
M
Verified Purchase
MYREEN
Lexington, US
★★★★★ 5
It works and I love it!
Scent: Smoky coffee, Size: 4 Fl Oz (Pack of 1)
I love this product.. been using it for a few months now. My hair is more manageable and my thinning crown looks and feels fuller. The smoky smell, am not bothered because it disappears after a few minutes. I use it twice a week, massage very little amount on scalp and hair, then the next day wash it off with shampoo. I used to need to dye my gray every 3 to 4 months when some appear. Now, it's been 4 months since my last visit to the salon. I noticed my hair has darken a bit. I can delay my salon visit for another month unless I need a haircut!! Yehey!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 19, 2025
P
Verified Purchase
Prime
Fort Morgan, US
★★★★★ 3
Good moisturizer. Rich scent.
Scent: Smoky coffee, Size: 4 Fl Oz (Pack of 1)
Raw Batana Oil provides goods moisturizing to hair and scalp and best applied with a little heat or steam. Pomade goes on easily once heated and does not feel heavy, greasy, or oily. Its rich fragrance eases on the nose after a short while. Difficult to say whether it is actually useful or whether it encourages hair growth. Leaves hair soft and easy to style.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 28, 2025
E
Verified Purchase
Elizabeth
Alexandria, US
★★★★★ 5
Great buy, good quality and really nice results!
Color: Dark, Color: Dark
I really like how silk and smooth this tanner feels! It’s not sticky tacky goop like some other brands can be and it’s really effective. Applying it went well as the product isn’t too thick or too thin, so making an even coat wasn’t an issue. It has a dark green tint which makes the product give its deep rich glow which is good for some medium toned to darker tone flesh colors. The effect is as though you’ve been in the sun deep in the tropics near the equator getting a daily golden caramel baked glow from some strong sun rays for a couple weeks. Works great and could be used for other than face in a pinch if needed...though you’ll probably want to buy a bigger bottle first because you’ll love it!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 26, 2020
L
Verified Purchase
LisaFrag
Houston, US
★★★★★ 5
Works great - don't let the dark color freak you out
Color: Dark
I am a reasonably fair skinned Caucasian person whose body can become moderately tan but my face does not, just burns and freckles. I don't tan my face at all and require a self tanner that makes my face color match my body. I have tried many expensive ones, and this is the best and most reasonably priced I have found. The stain works almost immediately and dries quickly so you have to work fast to smooth it evenly over your face. I skip the step of wearing a glove to apply and wash my hands immediately afterward but usually have to scrub with a wash cloth to get the color off. if you wait several minutes, you can add another layer to deepen the color (wash hands in between layers) but I use a generous amount with the first application so I usually don't have to. Most of the other facial self tanners I have tried have not been dark enough, even with multiple applications. This gives you a noticeable tan with just one application. Warning: it comes out of the bottle very alarmingly dark but it won't be dark like that after you apply it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 26, 2018

recommand products