Calcium nitrate is a nitrogen fertilizer that can also be used to give plants calcium.

I've read that you shouldn't combine calcium nitrate with sulfates and certain kinds of phosphorus (I believe this is because the combination may make certain of the nutrients so they don't absorb how they should or something).

My question is, if I have such as potassium sulfate and/or magnesium sulfate in my soil, could I get around the problem by spraying calcium nitrate on the leaves instead of adding it to the soil where the sulfates are? Would the plant absorb them all just fine, in this case?

This question is for plants in containers. If the kind of plant matters, this is for peppers, tomatoes and such.

1 Answer 1


Correct! Generally the rule of thumb I use is, if a combination of chemicals applied are not compatible with each other (that is, adversely affect the availability of another, thus affecting absorption into the plant), then use them separately. Most nitrates are readily absorbed through the leaf stomata, even more so than through the root hairs, so your idea should work quite well. Especially if you apply to the leaf undersides.

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