GH Feeding CalMag - Calcium and Magnesium Supplement

Green House Feeding CalMag is a high-quality water-soluble mineral fertiliser designed to prevent and correct calcium and magnesium deficiencies in all plant types. The formula contains nitrogen, calcium and magnesium in an easily absorbed form and is ideal for use with soft water, reverse-osmosis (RO) water, rainwater, as well as in hydroponic, coco and soil growing. Thanks to its high purity, the product contains no chlorine, sodium or heavy metals.

Green House Feeding CalMag is a professional mineral supplement developed to provide optimal amounts of calcium and magnesium – two vital elements for proper plant development. Calcium contributes to the formation of strong cell walls and stimulates the development of roots and new tissue, while magnesium is a key component of chlorophyll and plays a vital role in photosynthesis.

The product is particularly suitable when using reverse-osmosis (RO) water, rainwater or very soft water, where the natural calcium and magnesium content is insufficient. Adding CalMag restores the mineral balance and prevents typical symptoms such as interveinal chlorosis, necrotic spots, deformed leaves and stunted growth.

Thanks to its 100% water-soluble formula, nutrients become immediately available to plants. CalMag can be used through fertigation, hydroponic systems or foliar application, and is compatible with all main Green House Feeding mineral fertilisers – Hybrids, Short Flowering, Long Flowering and Booster – as well as nutrient programmes from other manufacturers.

Composition (EC fertiliser):

✔️ Total nitrogen (N): 13.5%

• Nitrate nitrogen (NO₃): 13.1%
• Ammoniacal nitrogen (NH₄): 0.4%

✔️ Calcium oxide (CaO): 16.7% (water-soluble)

✔️ Magnesium oxide (MgO): 6.0% (water-soluble)

✔️ EC at 1 g/L: 1.2 mS/cm

✔️ Does not contain:

• Chlorine
• Sodium
• Heavy metals

Benefits

✔️ Prevents and corrects calcium and magnesium deficiency

✔️ Suitable for reverse-osmosis (RO) water and rainwater

✔️ Improves cell-wall strength

✔️ Stimulates the development of a strong root system

✔️ Improves photosynthesis and chlorophyll formation

✔️ Supports the formation of healthy flowers and quality fruit

✔️ Ensures rapid absorption thanks to high solubility

✔️ Compatible with most mineral nutrition programmes

✔️ Can be used alone or with fertilisers from other manufacturers

✔️ Contains no chlorine, sodium or heavy metals

Application

Suitable for:

• Vegetable crops

• Fruit trees

• Flowers

• Ornamental plants

• Hydroponic systems

• Coco substrates

• Soil growing

• Fertigation

• Foliar feeding

• Professional and hobby growing

📋 Instructions for use

Base dosage

✔️ 0.1 – 0.5 g per 1 litre of water

For soft water (RO / rainwater)

✔️ 0.5 g/L water (about 0.6 EC)

For hard water or rich soil

✔️ 0.2 g/L, 1–2 times per week (as needed)

Foliar application

✔️ 0.2 g/L, every 10 days, only in the event of confirmed calcium or magnesium deficiency.

For automatic dosing systems

✔️ Preparation of concentrate: 10–15 kg product per 100 litres of water for systems such as Dosatron, Netafim and others.

⚠️ Important

• Do not mix Green House Feeding CalMag with other calcium supplements.
• When using the Green House Feeding programme, you can stop using CalMag around the 6th week of flowering and switch to GHF Calcium Chelate if you wish to continue supplying calcium without additional nitrogen.

💡 Tip from Urban Botaniks: If you use a reverse-osmosis (RO) system, Green House Feeding CalMag should be the first addition to the water before the other fertilisers. This will restore the required calcium and magnesium content and provide an optimal environment for the absorption of all other nutrients. 🌱