Wednesday, October 17, 2012

Composting Nuts

“Every oak tree started out as a couple of nuts who stood their ground.” -Anonymous

Yes, we may be “composting nuts” but this post is actually about composting nuts, you know, walnuts, pistachios, and almonds. More specifically about composting their shells since we will likely be eating the nuts.

That’s a Tough Nut to Crack
Nuts are supposed to be tough. They are built to withstand forces of nature like torrential rain storms, freezing temperatures, and squirrels.

As you might imagine, whole (unshelled) nuts take a long time to break down (and may even sprout) in your compost bin.

So, the first rule of nut composting is EAT YOUR NUTS. Raw, glazed, on a salad, in cookies, whatever. Crack ‘em, eat ‘em, and then compost the shells.

Nuts and Bolts
Nut shells are high in carbon, so be sure to balance with high nitrogen material like food scraps. Also, know that nut shells take a while to break down so you may need to screen them out once or twice.

But if a few pistachio shells incorporated in your soil with your finished compost drives you nuts, you probably need a new perfectionist-friendly hobby. Like building tiny ships in a bottle.

Warning: May Contain Traces of Nuts
I issue two warnings regarding Black Walnuts and salted peanuts.
  • Use caution when composting Black Walnuts. These are the native walnuts that look like green tennis balls on the ground not the English walnuts you buy in the store.
Black Walnuts contain a chemical called “juglone” which inhibits the growth of many plants, including tomatoes. The OSU Extension recommends composting Black Walnut bark and shells for at least 6 months to make sure the “toxic” juglone has broken down.
  • If you enjoy unshelled salted peanuts, beware. Too much salt in your compost is a bad idea which you will add if the peanut shells are still salted. Rinse the salt off in the sink before adding to your compost.
Otherwise, go nuts with your nuts.

Have you ever composted nut shells? How long did it take them to break down?


  1. Any idea about what to do with acorns? I get a bazillion of them in my back yard and it's a pain in the butt. If I leave any of them alone, they take root and then I have to spray them which I hate to do. I heard a rumor that pigs can eat them.

    1. I've never had too much of a problem with acorns despite the massive oak trees in my backyard. Our large squirrel population seems to take care of them. I've also heard you can eat them after some preparation to remove the bitterness, although I'll admit I've never tried this. I would recommend composting them maybe after smashing them with a hammer to speed up the process and discourage sprouting. You could also just put them in whole and screen them out if they have not decomposed when you harvest. Good luck!