Am I giving too much Calcium to my orchids?

[Alvaro78]

Hello everyone!

I have been trying to tweak the amount of fertilizer I give to my orchids but I was prompted with some questions about Calcium. I am using the RainMix fertilizer which follows the MSU formula but made available in Europe. The exact formula is 11,8N + 2,7P2O5 + 13,7K2O + 11,8CaO + 3,5MgO + 4,8SO3.

As you can see it has 11,8% of calcium. I water my orchids with tap water since it is really soft and I have been told in the past that it is not a problem but I checked the data of my water and it has 10 mg/l of Calcium which if I am correct is 10 ppm. I give my orchids about 100-125 ppm of N from the recommendations seen in the forum.

Now after seeing this and taking into account the amount of Calcium the RainMix fertilizer has (11,8%) I was wondering if you could tell me how many ppm of Calcium I am giving to my orchids since I am struggling to calculate it myself. I read that, without much testing done, it is recommended to give orchids about 40-80 ppm of Calcium and I am afraid of going overboard.

Thanks a lot for reading all this and I hope you can help me. I must say this forum (and the community in general) has been such a great source of information for my beginner brain and it has shown me how good of a community this one is in general full of great people so for that thank you again!