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Comment by camillomiller | Hacker News Reader

What about the ink and chemicals in the newspapers sheets that the author is using? Wouldn’t that stay in the soil and pollute the crops?

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As far as I understand, most commercially-used inks these days are soy-based, so shouldn’t pose an issue.

Yup! The general rule for sheet mulching is: no glossy print.

I know a lot of people have praised cardboard and I've used it too, but after sniffing some particularly smudged boxes from an Amazon order, I'm pretty hesitant now.

I'm less nervous about things like pizza boxes (if not too greasy). Even if there are contaminants, they are already in my food.

I just use 'plain' cardboard in my garden - the brown stuff with text printed in one colour. It's pretty easy to get hold of from supermarkets. The multicolour stuff I send for recycling.

Aren’t pizza boxes lines with PFAS or some other kind of forever chemicals which is why they can’t be recycled?

The ones in Ireland are basic cardboard. You can tell from the way the grease soaks through and the cardboard goes all limp. The constraint for recycling them here is that the items up for recycling must be "clean and dry", and a pizza box is neither after it has been delivered with pizza in it.

The microbes and fungi in the soil act as remediators for most organic compounds. Shouldn't be an issue, but you can always grow perennials in the bed that take time to grow rather than fast growing annuals if you're concerned.

I came here with the same question -- the ink. Why do you feel that the ink is an organic compound? Not sure if there is an easy answer here but this site: https://home.howstuffworks.com/pen4.htm seems to suggest colored inks are inorganic and contains heavy metals.

The thing is that there is a lot of variation in ink composition, so it's hard to say universally. That being said, fungi tend to sequester heavy metals in their mycelium, see https://krishisanskriti.org/vol_image/03Jul201502072615.pdf

But if you just compost the fungi, you are just back to where you started. With phytoextraction you have to incinerate the plant material afterwards. I know fungi aren’t plants, but similar principle.

You can harvest the mushrooms and throw them away.

The fruiting body of a mushroom often represents only a fraction of total biomass. It depends on the species, but what we see above ground is more analogous to a flower than an entire plant.

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