• EarthMix® Garden Products

Calcium: How It Improves Plant Health

Updated: May 22

Have you ever grown tomatoes only to have them rot on the vine, starting with the blossom end of the fruit? Or perhaps the tender new growth on an ornamental plant appears misshapen and stunted. These symptoms may be caused by a soluble calcium deficiency in the soil. Plants, much like humans, require a number of essential nutrients to thrive. Calcium is one of those nutrients, and is crucial for building resilient plant tissue and a healthy soil legacy.


Calcium is considered a secondary nutrient. Primary nutrients are the three numbers you typically see on fertilizer packaging—phosphorus, potassium, and nitrogen. However, plants need much more than these three nutrients to thrive. Calcium acts as an important building block for strong and hardy plant tissue. Similar in the way that it benefits humans, calcium fortifies plant cell structure, fostering sturdy growth.

When transferred from the soil to the plant, calcium is upwardly mobile. It migrates up the stem and through the foliage until it locks into the plant’s cell walls. Once there, calcium plays a critical role in fusing cells to build strong plant tissue. However, unlike many nutrients, once fixed within cell walls calcium does not move. It makes its permanent home within the cell, and thus, is unavailable to new growth. This can lead to calcium deficiencies in new foliage and in fruit. As the plant pushes out new leaves, fruits, flowers, and vegetables, there needs to be available calcium in the soil to migrate upward and into the plant to support this new growth.



Calcium also works as part of a larger metabolic system within the plant. It makes nutrients more easily accessible to plants throughout their life cycle. It has been shown to increase nitrogen absorption in a number of crops, resulting in increased foliage and yields. In ornamental plants, this results in fuller foliage and more abundant blooms. Calcium works in conjunction with other minerals to help plants to efficiently absorb nutrients throughout their life cycle. It can chelate toxic metals and ions, locking them in the soil so that they are unable to be absorbed by the plant.

Calcium also plays a vital role in improving soil friability and fertility. It acts to aerate dense soils and aggregate loose soils, increasing their water-holding and nutrient exchange capacity. Calcium essentially acts as a bridge between clay molecules, attaching to them and creating space within the soil structure. Added calcium can help to create a healthy, cakey soil structure when applied over time.


Calcium is readily available in most soil. However, when planting container gardens or raised beds it is necessary to recreate the natural environment for resilient plants. EarthMix® Proganix-O contains added calcium, and is a ready-to-use soil blend for potted arrangements, container gardens, and raised beds.




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