If you’re familiar with the classic milk advertisements praising calcium as a great way to build strong teeth and bones, then you shouldn’t be surprised to know that calcium is also essential for the “bones” of your plants (cell walls). 

The problem is, that knowing how much calcium to feed your plant is not always clear. Luckily Plant-Prod has over 75+ years of experience formulating water soluble fertilizers like Plant-Prod 15-0-15 Cal-Plus and Plant-Prod MJ Cal Kick

In this post, we’ll explain how much calcium you should be feeding your plant for the best results.

How Do I Know If My Plants Need Calcium?

All plants require a calcium source. Whether it’s coming from your water source or your
fertilizer program, calcium is an essential secondary nutrient. When it is lacking, there are some
tell-tale signs that are specific to calcium:

  • Low growth rate
  • Variable patterns of chlorosis on young leaves
  • Upward curling of leaves
  • Browning/necrosis of apical meristems (growing points)

There are also other plant-specific signs of calcium deficiency like blossom end rot in peppers and tomatoes.

calcium deficiency in plant


How Much Calcium To Feed?

How much calcium to apply and when you apply it is difficult to generalize for all types of
plants. Depending on the crops you are growing, you might need to seek further information by
contacting us here, or visiting our crops section for specific recommendations. As a general
rule, the amount of calcium in your water source and your crop will be the main
determining factors dictating how much calcium to feed.

Depending on the demands of your crop and the growth stage that it is at, calcium can be fed
between 50-200 ppm Ca. The initial amount in your water source can contribute to this over all
ppm level and should be taken into consideration when determining fertilizer rates.

Calcium based fertilizers should be fed as part of a balanced fertilizer program. This means
alternating feedings with a traditional NPK fertilizer, such as Plant-Prod 20-10-20 High Nitrate
or Plant-Prod 20-20-20 Classic.

The quality of the water soluble calcium fertilizer you use can also affect the growth of your
plants. Be sure you’re getting what you paid for when purchasing a water soluble calcium
fertilizer and that it’s dissolving completely. (Plant-Prod water soluble fertilizers won’t end up at
the bottom of your tanks or undissolved in spray bottles).

For more information on water-soluble fertilizers and adjusting your pH levels, check out some of our other publications below:


Master Plant-Prod Inc. has an extensive product line of 100% water soluble fertilizers and water soluble cannabis fertilizers. Cut your costs, and increase yields. For more information about chelated iron for plants, zinc fertilizer, and more, please contact us here.

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