General Organics 1gal CaMg+ Calcium Magnesium Supplement (4/CS)

What it is

CaMg+ is a liquid calcium-magnesium supplement from General Organics, the organic line under General Hydroponics. Calcium and magnesium are secondary macronutrients: many base nutrients supply them only in part, and reverse-osmosis or soft water supplies little of either, so growers add a dedicated Cal-Mag product to close the gap. CaMg+ is biologically catalyzed from oyster shell, dolomite lime and natural plant extracts, which is what distinguishes it from a purely synthetic calcium-nitrate / magnesium-nitrate blend. Plants take up calcium and magnesium as the divalent cations Ca2+ and Mg2+, and complexing a metal cation with organic acids or sugars (chelation) keeps it in solution rather than precipitating out where roots cannot reach it. In this listing it is the 1-gallon bottle, supplied as the “4/CS” case pack code (the exact number of units that maps to is a distributor packaging figure, disclosed as held below).

Guaranteed analysis and specifications

Why calcium and magnesium matter

Calcium and magnesium are secondary macronutrients — needed in smaller amounts than nitrogen, phosphorus and potassium, but still essential. Texas A&M AgriLife Extension lists magnesium’s major function in plants as chlorophyll formation, fat formation and metabolism, and calcium’s as root permeability and enzyme activity. Because magnesium is tied to chlorophyll, a shortfall shows first as interveinal yellowing on older leaves; calcium deficiency shows in new growth and fruit. A dedicated supplement is most useful when the base feed or water source is low in these two elements — for example when growing in reverse-osmosis or soft water, or in coco, where calcium and magnesium are readily displaced.

Why choose CaMg+

• Organic, not synthetic salts. CaMg+ is biologically catalyzed from oyster shell, dolomite lime and natural plant extracts, so it fits an organic or hybrid program rather than a purely mineral-salt feed.
• Two nutrients in one bottle. It supplies both 5.0% calcium and 1.0% magnesium, the two elements most often short together, so you dose one product instead of two.
• Simple, single label rate. The maker label rate reproduced by retailers is 1-2 tsp per gallon with every watering, the same across waterings rather than a multi-stage schedule.
• Case and multiple sizes. It is sold in a 1-gallon bottle here, one of several sizes in the line (see the comparison below).

Best uses

• Reverse-osmosis or soft water. RO and soft tap water carry little calcium or magnesium, so a Cal-Mag supplement restores what the base feed assumes is already in the water.
• Coco coir grows. Coco tends to hold and release calcium and magnesium unevenly, so many coco programs add a Cal-Mag product routinely.
• Correcting a deficiency. When older leaves show interveinal yellowing (magnesium) or new growth and fruit show calcium symptoms, a targeted supplement addresses the specific shortfall rather than raising the whole feed.
• Organic and hybrid programs. Because it is derived from oyster shell and dolomite lime, it suits growers who want an organic-sourced calcium-magnesium input.

Dosing and application

The label rate reproduced by retailers is to add 1-2 tsp per gallon of water with every watering. Always follow the rate and mixing order printed on the bottle you receive, and add it to solution before checking and adjusting pH. Any stage-specific, hydroponic-versus-soil, or millilitre-per-litre variations beyond this single rate are not reproduced on the retailer pages read this session, so they are held here rather than stated — consult the printed label or the maker feeding schedule for the exact program.

How the sizes in the line compare

General Organics offers CaMg+ in several sizes at the same guaranteed analysis; the only difference is volume. This table is factual — it does not claim one size is better, only which is which.

Where it fits in the range

For other nutrients and additives, browse the nutrients & additives category. If you want the same supplement in a different volume, the General Organics CaMg+ 2.5 gallon is the larger pack, and the General Organics CaMg+ listing covers the product line generally.