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Grubs in My Humanure Compost Pile


November 8, 2020

I finally got around to dumping 5 full buckets into my humanure compost pile today. (I started humanure composting in February of this year.) The pile temp had dropped down to ambient temp because it went about 6 weeks before getting "fed". When I was digging in the center of the pile to make room for the new 'contribution', I ran across at least 2 dozen LARGE grubs. (See attached photo.)

I found some information online that nematodes can be very helpful to control grubs, and in fact one writer specifically stated that adding nematodes to his/her compost pile completely got rid of the grubs in their pile.,and%20continue%20to%20kill%20grubs.

I'm hopeful that now the pile has been 'fed', the temp will go up to around 120 degrees F again, but there are bound to be places, especially in the corners, that don't get hot enough to kill the grubs and they will continue to thrive there undisturbed. What experience do you have re: controlling grubs in a compost pile? Thanks


Answer by RR: Other Master Composters may also respond with varying opinions. I personally love seeing the grubs in my compost. They are part of the food web that aids the decomposition process. They also help me  assess when my compost is “finished.” As long as the grubs are there, I know there is more undecomposed organic matter in my compost. The grubs will die off as the food source in my compost gets consumed. Happy composting.

Answer by PB: Grubs can be a problem in lawns; but, as RR responded, they are a form of “beneficial” in a compost pile.  I don’t have any experience in humanure composting as I live in a subdivision where the houses are close together; however, I occasionally find grubs in my larger raised bed in the spring when I am preparing it for planting.  I just pick them out, put them on the block wall and feed them to the birds (the robins particularly like them and tend to leave any earthworms I uncover alone before they burrow back down because they have this other tasty food source).

From original questioner: Thank you for the reassurances. I'll leave them in my compost pile and see what happens next spring.

Answer by RR: I agree.  I said I like the grubs in my compost, but they don’t belong in the garden.

Answer by JZ: Thanks for getting back to us. Just my offering. If when you collect / harvest your finished compost in the future you find any grubs, then they should be euthanized. Then you may add the dead grubs to your next batch. Live grubs should not be added to garden soil.  I’m guessing the pics which you sent are June Beetle larvae.

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