Cal-Mag Supplements

Last updated: November 17, 2021

What Does Cal-Mag Supplements Mean?

In horticulture, cal-mag supplements, short for calcium and magnesium supplements, refers to products that specifically contain high levels of both calcium and magnesium, which are two secondary plant nutrients that are required by all plants to grow, and are two nutrients that plants are often deficient in.

Cal-mag supplements are readily available at garden supply stores as pre-mixed products in powder or liquid form. Normally, varying levels of iron are also included to cal-mag supplements.

A grower can also tailor mix their own cal-mag supplements to achieve the best combination to more accurately provide the plant what it requires. Using this DIY method, growers can adjust their mixture to compensate for specific deficiencies, depending on the symptoms they are seeing in their garden.


Maximum Yield Explains Cal-Mag Supplements

Calcium and magnesium are considered to be the top two of three secondary nutrients plants need for healthy development. If plants do not receive an adequate amount of calcium, they can suffer from stunted growth, malformations, and brown foliage spotting. Magnesium deficiencies cause yellowing leaves and severely stunted growth. Without sufficient magnesium, plants cannot successfully photosynthesis sunlight and produce chlorophyll for green foliage.

Cal-mag nutrient deficiencies arise for a variety of reasons in the garden but two of the primary causes are high humidity and elevated temperatures. In hydroponics, plants are especially susceptible to calcium and magnesium deficiencies, the amount of which depends on the quality of the water supply, and the amounts of these nutrients that a grower's chosen base nutrients contain.

Once a cal-mag supplement is applied to the plant, the plant will immediately start to absorb the nutrients into its root system, where they will spread upward and outward to the foliage. These supplements can also be foliar sprayed.


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