Micronutrient Problem

My calculator treats all elements equally. My calculator does not discriminate among the various elements. This can lead to problems. For example, a formula that has an error of 2% in nitrogen and an error of 25% in copper is better than a formula with an error of 25% in nitrogen and 2% in copper.

Good Tip

If you plan to "include sulfur" in the calculations then you can "remove the sulfur" from micronutrient salts such as manganese sulfate, zinc sulfate, and copper sulfate.

For example, instead of specifying Copper Sulfate as 25.4% copper and 12.8% sulfur, you can specify Copper Sulfate as 25.4% copper and zero percent sulfur. The amount of copper needed is typically below 0.1 ppm. It makes no sense to include the amount of sulfur contributed by the copper sulfate in the calculations. Doing so can lead to having large errors in the NPK ratios.

You do not have to worry about this if you choose NOT to include sulfur in the calculations.

An extreme example is Ammonium Molybdate. Here you have molybdenum, a micronutrient, competing directly with nitrogen! It will be best to specify Ammonium Molybdate as 54.3% molybdenum and zero percent nitrogen. The same logic will apply to nitrate salts such as zinc nitrate, copper nitrate, etc.