Like their black walnut tree cousins, hickory tree nuts contain juglone, a toxic chemical that can cause some plants, including tomatoes, to wilt. Some compost aficionados are reluctant to compost hickory nuts because they do not want to spread juglone-laden compost throughout their garden. However, hickory nuts contain such low levels of juglone that they are safe for most plants. Proper composting practices eliminates the toxins present in hickory nuts as well.
Layer the compost into a pile no less than 3 feet square and no more than 5 feet square. Layer the pile so that nitrogen-filled material such as kitchen scraps and grass clippings alternate with carbon-laden materials including hickory nuts, hay and shredded leaves. The carbon layers should be twice as thick as the nitrogen layers.
Crush hickory nuts with a hammer to reduce them in size and help them break down faster. Bury them at the center of the compost pile so they are exposed to the high temperatures of the hot compost process. This will cause them to decompose faster, and neutralize the juglone.
Wet the compost pile with a garden hose until it is as damp as a wrung-out sponge.
Cover the pile with a tarp to keep away vermin and retain moisture.
Check the internal temperature of the pile daily with a compost thermometer. A hot-process compost pile should maintain a core temperature between 130 and 160 degrees F. Stir the compost with a pitchfork any time the temperature drops below 130 degrees F.
Allow compost to sit for a few weeks after it has been transformed into loose, fluffy soil so that it can finish. Finished compost has no active microbes in it that can harm the root structure of plants, and is pH neutral and free of juglone.