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CalMag + Iron Plant Supplement (32 oz) Quart | Concentrated Calcium Magnesium Iron for All Plants & Gardens | Makes Up to 315 Gallons | Prevents & Corrects Blossom End Rot | Blue Planet Nutrients

  • Based on 1,775 reviews
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Availability: Only 3 left in stock, order soon!
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Arrives Thursday, May 21
Order within 38 minutes
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Size: Quart


Features

  • CORRECT & PREVENT DEFICIENCIES: Feed CalMag to your plants as needed to prevent and correct common deficiencies such as blossom end rot and upward leaf curl.
  • CALCIUM, MAGNESIUM, IRON SUPPLEMENT: CalMag provides plants with calcium, magnesium, and iron which are key elements in photosynthesis, absorption & transport of nutrients within the plant, and are vital to the healthy development of all varieties of plants.
  • VERSATILE FORMULA: Can be fed to all varieties of plants growing in almost any type of garden such as hydroponic, soil, aeroponic, and all soil-less media! Blue Planet Nutrients CalMag supplement can be used along with other garden fertilizers and supplements.
  • EASY TO USE: Simply dilute a small amount per gallon of water and water your plants! CalMag can also be used as a foliar spray and as a soak for coco coir prior to use as a hydroponic growing medium.
  • BLUE PLANET NUTRIENTS: Trusted brand from Houston, TX providing high quality, professional grade garden fertilizers and supplements since 2010.

Brand: Blue Planet Nutrients


Item Weight: 32 Ounces


Item Form: Liquid


Liquid Volume: 32 Fluid Ounces


Specific Uses For Product: Calcium Magnesium Iron Fertilizer Supplement for All Plants and Gardens


Brand: ‎Blue Planet Nutrients


Item Weight: ‎32 Ounces


Item Form: ‎Liquid


Liquid Volume: ‎32 Fluid Ounces


Specific Uses For Product: ‎Calcium Magnesium Iron Fertilizer Supplement for All Plants and Gardens


Manufacturer: ‎Blue Planet Nutrients


Number of Items: ‎1


UPC: ‎609408403149


Unit Count: ‎32.0 Fluid Ounces


Product Dimensions: ‎5.25 x 2.4 x 7.5 inches


Item Weight: ‎2 pounds


Is Discontinued By Manufacturer: ‎No


Date First Available: ‎September 12, 2016


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, May 21

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews


  • great product
Size: Quart
works great for my gardening
Reviewed in the United States on June 9, 2025 by Amazon Customer

  • This stuff works really well
Size: Quart
The media could not be loaded. Works extremely well at correcting or preventing calcium magnesium or iron deficiencies I use it daily and have been using it for years same company same product and have not been disappointed not even once this stuff is amazing not only that but it corrects the problem fast and is fairly cheap! ... show more
Reviewed in the United States on May 8, 2024 by Chris beck

  • Nice addative for plant health.
Size: Quart
Big difference in plant health. Works well for cannabis.
Reviewed in the United States on February 16, 2026 by Phillip m Bohde

  • Good product
Size: Quart
Recommend great easy to use
Reviewed in the United States on April 14, 2021 by Amazon Customer

  • Great for Indoor/Outdoor Gardens
Size: Gallon
I make my own plant food mixtures with liquid seaweed for my indoor and outdoor plants, as well as supplementing my AeroGarden veggies for continued growth. This gave me tasty cherry tomatoes for 200 days on my kitchen counter. Now I'm growing herbs, lettuce, and chilies with continuous growth. Very happy. A little bit goes a long way! My houseplants also grow well with these nutrients and I'm looking forward to spring to start my garden outside again. It did wonders for my veggies outdoors. They continued to grow until our first snowfall. ... show more
Reviewed in the United States on January 26, 2022 by Cheryl Cervantes

  • Perfect
Size: Quart
Perfect
Reviewed in the United States on June 8, 2025 by JAMES

  • Good for price
Size: Gallon
Used a quart from blue planet liked its quality bought a gallon highly recommend over the high priced brands .thumbs up
Reviewed in the United States on January 30, 2022 by james beyer 3

  • Calcium Magnesium AND IRON.
Size: Quart
Worked great reviving my citrus orange tree that started to yellow from nutrient deficiency. While I use Epsom salt as a foliage and in ground supplement, it did not do enough to make my leaves green again. When I found this I was hoping the iron or calcium would help and it did! Never figured out which specific nutrient it was deficient in but def did the job. ... show more
Reviewed in the United States on September 20, 2020 by Spman

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