What is in the plant fertilizer?

Question

Okay, so i just bought 3 lb package of Scotts Select Plant Food: All Purpose. It's NPK value is 10-10-10. I need to seperate each kind of pellet that is in it. On the "ingredient" list of chemicals on the back, Nitrogen is Ammoniacal and Urea Nitrogen; Phosphorus is Available Phosphate; Potassium is Soluble Potash. There are 3 different colored pellets in the fertilizer. One kind is white (I believe this is the nitrogen), one kind looks like a rock and is dark/light greyish, and the last kind is rock-like and seems to be peach-pinkish. If anyone can enlighten me as to which pellet is which nutrient, I would be very thankful!

Answer 1

Considering no artificial color were added into the compound, white, colorless, just like sugar, but with rounded edges, it is either urea or ammonium nitrate, which contains nitrogen. So i think u are right to say that the white pellet is nitrogen.

U can justify if the white pellet is nitrogenous element by putting it in water. If it is readily soluble, then u can say pretty sure that it is a nitrogen fertilizer. P and K is not very soluble.

The peach-pink must be potash, just like the murrate of potash, and the greyish pellet must be phosphorus, like the DSP or TSP.

However, there are fertilizer company purposely coloured their product. Nitrophoska green for example, is colored green and containing NPK in the proportion of 10:10:10. There are also different compound fertilizer (fertilizers with more than one element in the formulation, such as N, P, K, Ca etc) with specific color just to distinguish them with different NPK ratio.

Usually, we can tell the element in a fertilizer, if it is a straight fertilizer (only one element in the formulation) and no artificial color being added into the formulation.

Answer 2

The phosphate should be the white and the potassium should be the gray. That leaves only the nitrogen which must be peach-pinkish. Though phosphate can also be red so that could be the peach-pink one. But I'm going with:

White: phosphate
Grayish: potassium
Peach-Pink: Nitrogen

Could be wrong but I researched this a bit and that is what I came up with. The white one and pink one could be reversed. Unlikely though.

Edit: I gave this question a star because one of my contacts is a permaculture engineer (a "botanist" for all intents and purposes). Thought he would see the star on his page. Would you like me to send him a private message?

Answer 3

That's a good question. I'm a botanist/restoration ecologist and I've honestly never looked into it.

If I were to just guess (that's all this is) I would say Professor Armitage gave you a good answer.