Search  for anything...

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 1,735 reviews
Condition: New
Checking for product changes
$15.95 Why this price?
Save $59.03 was $74.98

Buy Now, Pay Later


As low as $3 / mo
  • – 4-month term
  • – No impact on credit
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout. Payment plans are offered through our trusted finance partners Klarna, PayTomorrow, Affirm, Afterpay, Apple Pay, and PayPal. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

This item is eligible for return within 30 days of receipt

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.


Availability: In Stock.
Fulfilled by Amazon

Arrives Dec 19 – Dec 20
Order within 5 hours and 52 minutes
Available payment plans shown during checkout

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: 1 Quarts


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


Is Discontinued By Manufacturer ‏ : ‎ No


Product Dimensions ‏ : ‎ 5.25 x 2.4 x 7.5 inches; 2 Pounds


Date First Available ‏ : ‎ September 12, 2016


Manufacturer ‏ : ‎ Blue Planet Nutrients


Best Sellers Rank: #34,228 in Patio, Lawn & Garden (See Top 100 in Patio, Lawn & Garden) #955 in Garden Fertilizers


#955 in Garden Fertilizers:


Customer Reviews: 4.7 4.7 out of 5 stars 1,735 ratings


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Dec 19 – Dec 20

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.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Top Amazon Reviews


  • 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

  • Prevents deficiencies commonly found in plants lacking micronutrients
Size: Quart
This stuff works. Add 5ml of Blue Planet Nutrients CalMag per gallon of water. Mix well. Check and adjust pH. I grow in soil and CalMag prevents deficiencies that manifest themselves in problems with my leaves.
Reviewed in the United States 🇺🇸 on May 24, 2022 by PhatDrewB

  • Great stuff
Size: Quart
I keep trying other brands but I just keep coming back to this one plants love it
Reviewed in the United States 🇺🇸 on August 4, 2022 by James Sadler

  • If it worked, I couldn't tell
Size: Quart
I bought this because someone recommend I put calcium in my tomatoes. I didn't see any difference after using this. Pretty dissapointed :/
Reviewed in the United States 🇺🇸 on September 22, 2022 by Jenn

  • Just what the green thumb needed
Size: Quart
Great for controlling boytum end rot
Reviewed in the United States 🇺🇸 on July 9, 2022 by Nelson Correll

  • Plant feed supplement
Size: Quart
I add about 2ml to a gallon of water for young plant health. Hopefully helpful, it hasn't killed them yet. The jury is still out on whether it helps with observed leaf coloration. I was primarily interested in the calcium and magnesium but the iron is likely a welcome bonus.
Reviewed in the United States 🇺🇸 on March 28, 2021 by wild bill

  • 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

  • Tomato peppers
Size: Quart
Best supplement to stop bottom rot
Reviewed in the United States 🇺🇸 on May 4, 2022 by eric d

Can't find a product?

Find it on Amazon first, then paste the link below.