---
product_id: 42491759
title: "CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce"
brand: "humboldts secret"
price: "275 zł"
currency: PLN
in_stock: true
reviews_count: 8
url: https://www.desertcart.pl/products/42491759-calmag-and-iron-calcium-magnesium-and-chelated-iron-nutrient-fertilizer
store_origin: PL
region: Poland
---

# Enhances flowering & fruiting Boosts lush vegetative growth Fortifies stems & structure CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce

**Brand:** humboldts secret
**Price:** 275 zł
**Availability:** ✅ In Stock

## Summary

> 🌱 Unlock your garden’s secret weapon for unstoppable growth!

## 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 | 32 Ounce by humboldts secret
- **How much does it cost?** 275 zł with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.pl](https://www.desertcart.pl/products/42491759-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 Nutrient Recovery:** Fast-acting formula corrects deficiencies and accelerates photosynthesis for healthier, more resilient crops.
- • **Maximum Mineral Absorption:** Optimized chelated iron blend ensures superior uptake and utilization of essential nutrients.
- • **Fruiting Success Guaranteed:** Prevents blossom end rot and promotes firm fruit set for bountiful, high-quality harvests.
- • **Strength at Every Growth Stage:** Calcium, magnesium & chelated iron deliver balanced nutrition for vigorous plants from seedling to bloom.
- • **Versatile for Any Garden Setup:** Perfectly formulated for hydroponics, soil, coco coir, or RO water systems—grow confidently anywhere.

## Overview

Humboldts Secret CalMag & Iron is a premium 32 oz liquid nutrient fertilizer designed to deliver calcium, magnesium, and chelated iron efficiently across hydroponic, soil, coco, and RO water systems. It supports strong stems, vibrant foliage, and abundant flowering and fruiting by preventing nutrient deficiencies and enhancing mineral absorption, making it an essential supplement for professional and home growers seeking consistent, high-quality yields.

## Description

Full description not available

## Features

- 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 |
|---------------|-------|
| Liquid Volume | 32 Fluid Ounces |
| Specific Uses For Product | Hydroponic |
| Target Species | Plants |
| Coverage | Medium |
| Item Form | Liquid |

## Product Details

- **Brand:** Humboldts Secret
- **Item Form:** Liquid
- **Liquid Volume:** 32 Fluid Ounces
- **Specific Uses For Product:** Hydroponic
- **Manufacturer:** Humboldts Secret

## Images

![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce - Image 1](https://m.media-amazon.com/images/I/71fXSXEGgLL.jpg)
![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce - Image 2](https://m.media-amazon.com/images/I/81J1gCLqPEL.jpg)
![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce - Image 3](https://m.media-amazon.com/images/I/81eCWuN+8JL.jpg)
![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce - Image 4](https://m.media-amazon.com/images/I/91mCokPNUoL.jpg)
![CalMag & Iron | Calcium, Magnesium & Chelated Iron Nutrient Fertilizer | Hydroponic Supplies for Vegetative & Flowering Growth in Soil, Coco, Hydroponics or RO Water | 32 Ounce - Image 5](https://m.media-amazon.com/images/I/81NW+7yZAeL.jpg)

## Available Options

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

## Customer Reviews

### ⭐⭐⭐⭐⭐ Works great 👍
*by S***A on May 1, 2025*

Works great 👍

### ⭐⭐⭐⭐⭐ Worked great.
*by J***. on November 25, 2024*

Had some maple trees that are prone to iron deficiency. Got this so I could solubilize it and apply to the roots. Couldn't see exactly how much, wrote the company an e-mail and heard back the next day with specific amounts and instructions. Amazing! Pretty rare to get that kind of corporate response. Best of all, my trees snapped right back (about 3 weeks). Apply once a month and they just keep getting more and more green. Will definitely buy again to start applying next spring. Saved my trees lives, literally.

### ⭐⭐⭐⭐ Great product as always
*by S***  on March 22, 2025*

Great product works well

## Frequently Bought Together

- Humboldts Secret Calcium, Magnesium and Iron Supplement – Hydroponic Supplies – Liquid Nutrient Fertilizer – Supports Vegetative and Flowering Stage – 1 Quart
- Humboldts Secret Sweet & Sticky – Carbohydrate and Saccharide Energy Source – Enhance Aroma and Flavor of Plants – Potting Soil for Indoor Plants – Energy for Plants – 32 Ounces
- Humboldts Secret Set of A & B Liquid Hydroponics Fertilizer - World's Best Nutrient System – Hydroponic Nutrients for Outdoor, Indoor Plants – Supports Vegetative and Flowering Stages of Plants

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*Product available on Desertcart Poland*
*Store origin: PL*
*Last updated: 2026-01-26*