can you compost nuts?
Yes, but chop them and keep black walnut apart — nut kernels run up to 70% oil, so they break down slowly and rodents hunt for them.
breaks down in 3–8 months chopped; longer left whole
C:N ≈ 18:1
which bins can take it?
- hot pile yes
- cold pile caution
- worm bin caution
- bokashi yes
- tumbler caution
- curbside yes
- hot pile: Heat and chopping together are what get microbes through the oil.
- cold pile: Whole nuts sit for a year in a cold pile and attract squirrels and mice the entire time; keep black walnut out of cold piles entirely.
- worm bin: Oily food sours a worm bin — crumbs at most, if at all.
- tumbler: Fine for ordinary nuts; keep black walnut out of a drum, because juglone only degrades under hot-pile conditions.
why?
A kernel is a seed's energy store, and most of that store is fat: almonds are roughly half oil and pecans closer to 70%, which is why they decompose at a fraction of the speed of an equivalent volume of fruit. Fat also keeps them interesting to rodents for months instead of days. Black walnut is a separate issue — its tissues carry juglone, a compound toxic to tomatoes, peppers, and several other garden plants.
how to prep it
- Chop or crush kernels before they go in
- Bury them under browns so rodents can't smell them
- Rinse salted or seasoned nuts
- Compost black walnut in a hot pile only, and cure that batch before garden use
watch out for
- Juglone from black walnut degrades in a well-aerated hot pile over a couple of months, but extension programs still advise keeping that compost away from tomatoes and peppers.
- Salted and honey-roasted nuts bring sodium and sugar along — trivial in a large pile, worth rinsing off for a small one.
often confused with
- Walnut Shells — Shell and kernel get different verdicts: one is slow woody carbon, the other is oily food.
quick answers
Do nuts attract squirrels to a compost bin?
Reliably. Squirrels find them by smell and remember the spot, so nuts near the surface mean repeat visits all season. Burying them in the pile's center is the only fix short of a closed bin.
Are moldy nuts safe to compost?
Yes, in a hot pile. The aflatoxin warning applies to eating moldy nuts; in compost the kernel is just oily organic matter, and pile heat plus competition from other microbes knocks the mold back.