---
product_id: 68507987
title: "CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 1 Gallon"
brand: "humboldts secret"
price: "590.74 DT"
currency: TND
in_stock: true
reviews_count: 8
category: "Humboldts Secret"
url: https://www.desertcart.tn/products/68507987-calmag-and-iron-calcium-magnesium-and-chelated-iron-nutrient-fertilizer
store_origin: TN
region: Tunisia
---

# Fast-acting nutrient recovery Supports all growth stages 128 fl oz liquid concentrate CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 1 Gallon

**Brand:** humboldts secret
**Price:** 590.74 DT
**Availability:** ✅ In Stock

## Summary

> 🌿 Unlock your garden’s secret weapon for lush growth & vibrant blooms!

## Quick Answers

- **What is this?** CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 1 Gallon by humboldts secret
- **How much does it cost?** 590.74 DT with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tn](https://www.desertcart.tn/products/68507987-calmag-and-iron-calcium-magnesium-and-chelated-iron-nutrient-fertilizer)

## Best For

- humboldts secret enthusiasts

## Why This Product

- Trusted humboldts secret brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Rapid Deficiency Fix:** Targets yellowing & blossom end rot with fast absorption
- • **Long-Lasting Concentrate:** Just a capful per gallon means your garden stays thriving season after season
- • **Versatile Growth Booster:** Optimized for soil, coco, hydroponics & RO water setups
- • **Maximized Nutrient Uptake:** Chelated iron ensures plants get every drop of essential minerals
- • **All-in-One Nutrient Powerhouse:** Calcium, Magnesium & Chelated Iron for unstoppable plant health

## Overview

Humboldts Secret CalMag & Iron is a premium liquid fertilizer delivering calcium, magnesium, and chelated iron in a fast-absorbing formula. Designed for hydroponic, soil, coco, and RO water systems, it prevents nutrient deficiencies, strengthens stems, enhances leaf color, and supports vigorous vegetative and flowering growth. Ideal for both indoor and outdoor gardens, this 1-gallon concentrate ensures maximum nutrient uptake and helps prevent common issues like blossom end rot, making it a must-have for professional and hobbyist growers alike.

## Description

desertcart.com : Humboldts Secret CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 1 Gallon : Patio, Lawn & Garden

Review: This stuff WORKS!! - This stuff is great! My pepper plants were turning yellow and had blossom end rot so they were getting a lottlw rotten hole before they were even ready to pick. I read online that several ppl recommended this for that problem. It was like a miracle, I used it twice and my plants turned green again and the peppers started growing perfectly! I kept using them as recommended and got so many beautiful peppers from my plant all summer! Life saver! Plus it is so concentrated, you only use about a cap full with a gallon of water so it will last FOREVER!
Review: Humboldts - Very nice quantity & quality

## Features

- Packaging Update: You may receive previous or updated packaging during our transition. Same formula, same performance. Strength for Every Stage - Humboldts Secret supplement with cal mag for plants delivers calcium, magnesium, and chelated iron to prevent deficiencies. It fortifies stems, improves leaf color, and supports flowering and fruiting plants for vigorous, healthy growth in any type of garden.
- Fast-Acting Plant Recovery: Our balanced formula with calmag and chelated iron targets issues caused by nutrient imbalances, helping plants recover quickly. It boosts photosynthesis, nutrient transport, and root strength in vegetables, flowers, and herbs grown indoors or outdoors.
- Maximum Absorption Power: Using our cal-mag for plants blend with added iron improves uptake efficiency, ensuring these essential minerals are fully utilized. It supports lush vegetative growth and abundant blooms, delivering consistent results for home or commercial growers.
- Reliable Across All Setups: Humboldts Secret cal mag fertilizer with iron works in hydroponics, soil, and container gardens. It strengthens plant structure, enhances fruit quality, and ensures balanced nutrition in indoor and outdoor systems for dependable, healthy harvests.
- Focused on Fruiting Success: Our formula with calcium and magnesium for plants plus chelated iron benefits crops in coco coir or reverse osmosis water. It helps prevent blossom end rot, promotes firm fruit set, and improves nutrient absorption for strong, productive plants in challenging conditions.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B01GB23TD0 |
| Best Sellers Rank | #14,341 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #531 in Garden Fertilizers |
| Brand Name | Humboldts Secret |
| Coverage | Medium |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,037) |
| Global Trade Identification Number | 00648260730406 |
| Item Form | Liquid |
| Liquid Volume | 128 Fluid Ounces |
| Manufacturer | Humboldts Secret |
| Mixing Ratio | 2-5 ml/gallon |
| Model Number | CalMag & Iron |
| Specific Uses For Product | Hydroponic |
| Target Species | flowering plants |
| UPC | 648260730406 |
| Unit Count | 128 Fluid Ounces |

## Product Details

- **Brand:** Humboldts Secret
- **Global Trade Identification Number:** 00648260730406
- **Item Form:** Liquid
- **Liquid Volume:** 128 Fluid Ounces
- **Specific Uses For Product:** Hydroponic

## Images

![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 1 Gallon - Image 1](https://m.media-amazon.com/images/I/71E5ugjm48L.jpg)

## Available Options

This product comes in different **Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ This stuff WORKS!!
*by J***7 on January 30, 2026*

This stuff is great! My pepper plants were turning yellow and had blossom end rot so they were getting a lottlw rotten hole before they were even ready to pick. I read online that several ppl recommended this for that problem. It was like a miracle, I used it twice and my plants turned green again and the peppers started growing perfectly! I kept using them as recommended and got so many beautiful peppers from my plant all summer! Life saver! Plus it is so concentrated, you only use about a cap full with a gallon of water so it will last FOREVER!

### ⭐⭐⭐⭐⭐ Humboldts
*by T***N on March 5, 2026*

Very nice quantity & quality

### ⭐⭐⭐⭐⭐ Works well
*by E***E on March 18, 2026*

My tomatoes are doing much better. No ugly black spots on the bottom.

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**Shop now:** [https://www.desertcart.tn/products/68507987-calmag-and-iron-calcium-magnesium-and-chelated-iron-nutrient-fertilizer](https://www.desertcart.tn/products/68507987-calmag-and-iron-calcium-magnesium-and-chelated-iron-nutrient-fertilizer)

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*Product available on Desertcart Tunisia*
*Store origin: TN*
*Last updated: 2026-08-06*