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Mill Bay, British Columbia

When looking at the application/mixing rate of Masterblend 4-18-38 the manufacturer recommends a 3 part mix (adding magnesium sulphate and calcium nitrate) for a complete formula.

https://www.masterblend.com/4-18-38-tomato-formula/

In the instructions, it clearly states to mix the 4-18-38 first, add the magnesium sulphate next and then lastly the calcium nitrate. “NOTE It is important that the Masterblend and Magnesium Sulphate are completely dissolved before adding the Calcium Nitrate to prevent nutrient lockout. Do not combine concentrates.”

OK, very straightforward instructions. My question is, is this the same for all other blends that I do when adding calcium nitrate? For example, same precautions for Ureamate or the Growth Products liquids or the RAW soluable that we use in our rotation.

Should I always add the calcium nitrate last? And why?? What is the scientific/chemical reaction to avoid that nutrient lockout that will obviously take place.

Respectfully, no guesses please as I’m looking for something based on science and have not found the answer myself via Mr. Google. Of course my lovely growing partners just said “why don’t you just email the manufacturer?”

Thanks in advance/Glenn

6/16/2023 12:10:47 PM

Littlerock, WA

The reaction of sodium sulfate and calcium nitrate gives sodium nitrate and calcium sulfate. Calcium sulfate will be precipitated in the reaction, and sodium nitrate is found in the fertilizer solution. It could potentially clog up your drip lines if you get the precipitate in there.

6/16/2023 12:27:22 PM

Littlerock, WA

Calcium nitrate can be tricky to mix with other fertilizers. If you mix it with ammonium phosphate, typically found in balanced mixes like 20-20-20, you form calcium phosphate which is insoluble. Same with magnesium sulfate mixed with calcium nitrate, it makes calcium sulfate with isn't very soluble either. I would do a jar test if I were you using the same ratios. I have made barrel mixes for fertigation and I can generally reduce precipitates using these chemicals by predisolving them, but not completely eliminate them.

6/16/2023 12:37:33 PM

Western NY

Glenn, by the look of your pictures I think you already have your soil tuned up pretty good - I'm not sure you'll need the extra nitrogen.

6/16/2023 2:16:58 PM

Mill Bay, British Columbia

Thanks Cindy, I’ll do some more reading, I appreciate that.

Andy, thanks for that too!! I’m looking ahead to be ready after I get tissue testing done and an additional soil test. Richmond Dave worked pretty diligently with me and the Langley Soil estimator, so yeah I hope we are dialed in.

6/16/2023 3:09:30 PM

Torrance, Ca.

Go golfing and good chatting yesterday my friend!;)


Keep a close eye on the Richmond guy!

6/17/2023 1:09:17 PM