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Emerald Harvest Cal-Mag

From £19.95
In stock
Grouped product items
Emerald Harvest Cal-Mag - 950ml Code: 4093
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Emerald Harvest Cal-Mag - 3.79 Litre Code: 4094
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Prevent & treat nutrient deficiencies with Emerald Harvest Cal-Mag. 

It's a calcium (3%) & magnesium (0.5%) additive in coco, which holds onto calcium, it's a neal crop-saver. Whatever your media, it provides chelation to help nutrient absorption.

Not only does it prevent deficiencies - it improves growth. Calcium regulates growth, and magnesium is key for chlorophyll production (photosynthesis!). 

  • Calcium (3%) & magensium (0.5%) additive
  • Prevent & treat nutrient deficiencies
  • Regulate growth & chlorophyll production
  • Coco essential!
  • NPK: 2-0-0

How It Works

Caclium and magnesium are both macronutrients. Plants need them to survive. 


Calcium is used to thicken stems and your structure by binding cell walls. It's crucial for growth. A deficiency of it makes it tougher for plants to cope with temperature and environmental stresses. 

Since calcium is involved in processes that affect the uptake of other nutrients, a shortage of calcium can increase the likelihood of other nutrient deficiencies. 


Magnesium is in chlorophyll - the green substance that absorbs light for photosynthesis.  

If you've got high intensity lights, or plants are growing rapidly, you don't want to risk a magnesium shortage. 

In Coco

Coco is known for its calcium draw. It has a tendency to hold onto calcium, making it unavailable to your plants. For this reason, you should always use a Cal-Mag in coco. 

Guaranteed Analysis

Total nitrogen: 2.0%

  • 0.1% ammoniacal nitrogen
  • 1.9% nitrate nitrogen

 Calcium 3.0%

Magnesium 0.5%

How To Use

Use as needed, starting at 0.25ml/L, working up to a maximum of 1.25ml/L

Caution: do not aerate or use in any bubblers

Emerald Harvest Feed Chart
  Cali Pro - Grow A  Cali Pro -Grow B  Cali Pro -Bloom A Cali Pro -Bloom B Emerald Goddess  King Kola Honey Chrome Root Wizard
Cuttings / Seedlings   0.5ml  0.5ml  - - - -
Transplanting 0.75ml  0.75ml  -  -  -  -  -
Early Veg 1ml 1ml  - 1.5ml   - 1ml 3.75ml 
Late Veg  1.25ml 1.25ml  - 1.5ml    - 1ml
Transition  1.25ml  1.25ml  1.5ml  1ml  1ml  -
Flowering (Week 2)  -  -  1.25ml  1.25ml  2ml 2ml  2ml 3.75ml 
Flowering (Week 3)  -  -  1.25ml  1.25ml  2ml 2ml  2ml
Flowering (Week 4)  -  -  1.5ml  1.5ml  2.5ml 3ml  2ml
Flowering (Week 5)  -  -  1.5ml  1.5ml  2.5ml 3ml  2ml
Flowering (Week 6)  -  - 1.5ml 1.5ml  2.5ml 2ml 2ml 
Flowering (Week 7)  -  - 1.5ml 1.5ml  2.5ml 2ml 2ml 
(Week 8)
 -  - 1.5ml 1.5ml  1.25ml 1ml 1.5ml  -  
(Week 9)
 -  -  0.25ml  0.25ml  -  - 1.5ml

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