House & Garden CalMag Dry Calcium-Magnesium Supplement 12-0-0, 25 lb

Dry Calcium and Magnesium Supply for Larger Feeding Programs, 25 lb

Calcium and magnesium shortfalls slow vegetative growth and flowering, and they show up often when you feed with reverse osmosis water or soilless media. House & Garden CalMag is a dry, water-soluble powder that adds both nutrients to your reservoir or feed tank. It carries a 12-0-0 analysis, so it also contributes nitrogen. Dissolve it in water first; never apply the dry powder directly to growing media.

This 25 lb unit suits growers who mix nutrients regularly. It gives a home grower with several tents a long-lasting supply, and a commercial room a bulk size that cuts reorder frequency.

Key Features & Benefits

• Calcium and magnesium in one powder — one product covers both secondary nutrients.
• 12-0-0 analysis — adds nitrogen with no phosphorus or potassium, so it will not shift your base feed in those two areas.
• Dry, water-soluble format — dissolves into your feed water and stores more compactly than a liquid.
• 25 lb unit size — a bulk quantity for frequent mixing.

Who Should Use House & Garden CalMag

Growers running hydroponic systems, coco coir, or greenhouse and indoor rooms, especially those who feed with RO water, will find it useful for supplying calcium and magnesium.

About House & Garden CalMag

House & Garden CalMag (product code HGCM25LB) is a calcium and magnesium nutrient supplement with a 12-0-0 NPK analysis. It is sold as one 25 lb unit. A safety data sheet and House & Garden feed charts are available from the manufacturer.

Frequently Asked Questions

Q: What does the 12-0-0 mean?
A: The three numbers are nitrogen, phosphorus and potassium. CalMag lists 12 for nitrogen and 0 for both phosphorus and potassium.

Q: Can I sprinkle the powder on my media?
A: No. Dissolve it in water first and feed the solution. Applying dry powder directly to growing media is not recommended.

Q: Why would I add a calcium-magnesium supplement?
A: Water with low mineral content, such as reverse osmosis water, and soilless media like coco coir often supply too little calcium and magnesium. A supplement fills that gap in your feed.

Q: Is a dry powder different from a liquid supplement?
A: A dry powder is generally more compact to ship and store, but you must dissolve it fully before use. Liquids are premixed and quicker to dose.

Q: How much should I use?
A: Follow the manufacturer's feed chart and label for your system and stage. Start at the lower end if your environment is not ideal.

Q: How should I store it?
A: Keep the container sealed and dry, and store it out of reach of children. Avoid skin and eye contact and wear protective clothing when handling.