Mealworm Frass composition

I recently had my mealworm frass analyzed for nutrient content. Results just came back today, super exciting!

Nitrogen: 2.52% Phosphorous: 1.9% Potassium: 2.52%

How can I increase these values? I presume it all varies based on what I feed them, but what would I feed mealworms to increase their frass N/P/K values?

Thank you!


  • Not sure why want to do this. N-P-K formulas are by weight in terms of 100 units of measurement (metric or other). So 10-10-10 formula would mean 10lbs + 10lbs+10lbs per 100lbs of total weight, meaning out of every 100 lbs of this formulated product 70lbs is not an atom of either N-P-K.

    The different N-P-K amounts in formulas are then used to determine how much product need to meet users need per area wish to cover. If you did not have say 10-10-10 but only 1-1-1 you can still get what you need per area wish to cover, just require more pounds of the lower product used to get total want to apply.

    Your frass rounding up is 2.5-2-2.5 (N-P-K), which is fairly even proportioned. Here is a fertilizer usage for greenhouse tomato growing that might reveal some commercial usage. All numbers are in the order of N - P - K.

    From tomato seedling to 5 leaf stage 3 to 5 (N) - 0.3 to 0.6 (P) - 3 to 5(K); 5 leaves to1st flower 2.8 to 4 - 0.2 to 0.4 - 2.5 to 4; during early fruit set 2.5 to 4 - 0.2 to 0.4 - 2.5 to 4; at 1st ripe fruit to 3.5 - 0.2 to 0.4 - 2 to 4; during harvest period 2 to 3 - 0.2 to 0.4 - 1.5 to 2.5.

    Showing that if you wanted to use your frass as the basis for tomato greenhouse crop it only needs a bit more nitrogen & potassium (K) to 5 leaf & only a bit more nitrogen until 1st flower. To feed mealworms extra protein to get them produce frass with more residusl protein is an expensive tactics, since the little nitrogen fertilizer needed to supplement frass nitrogen is cheaper than protein's nitrogen. As for adding a bit of potassium (K) corn cob ash is about 30% potassium if can't afford potash (K2O).

    If you are hoping to get more P (phosphorus) in the frass, again I am not sure why. In fertilization it is the most needed nutrient that limits growth & excesses of phosphorus can block other nutrients being taken up. For example really excessive phosphorus (P) can contribute to calcium deficiency & also cause iron to be held back in the growing medium.

  • edited August 2017

    I didn't even stop to consider making it higher wasn't necessary. I remember seeing a 4-3-2 frass, just figured that's what I should aim for. But I will try promoting my 2-2-2 and see how it is received.

    Thank you!

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