Adding cardboard to compost

Am I right in thinking that (if you do or are trying to garden organically), you need to be careful about adding cardboard to the compost heap?

I’m sure I’ve read somewhere (might have been one of @jackwallington 's blogs) that cardboard can contain chemicals and other nasties.
I use cardboard boxes to cover my compost heaps and leaf mould pile and add brown paper bags which I use to line my compost caddy, but I don’t often add shredded cardboard to the mix because I’m not sure about the glue etc.

I’ve looked online, but I’m not sure who to trust as one source was advising adding tumble drier and vacuum lint to the heap (which are surely full of microplastics and other inorganic things!).

Any definitive information much appreciated.

I personally add shredded cardboard (e.g. egg boxes) and brown paper to my closed compost heap as brown material and have had no I’ll effects.

I avoid shiny card; and, I think more so in the past, you needed to avoid mineral-based ink (less used today?); I am not aware of any detailed tests, but better safe than sorry to avoid plastics and persistent chemicals. I also avoid very gluey boxes (I have had some that were excessively over-glued) or ones with tape that cannot be removed.

I have used cardboard with a compost layer on top to suppress weedy areas. And also use it to lay on paths before laying woodchip.

I have no experience of laying card sheets onto the heaps (as mine is closed). Anyone else have any experiences using card?

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I use as much cardboard as I can. I take off cellotape but every eggbox and delivery box goes in the open bin. When it becomes wet, I tear it up. I use big folder pieces as a liner. I’d say use as much as you can get. Not shiny stuff of course. Hope that helps.

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The advice from Julie and Beloved Porcupine is perfect :slight_smile: I just have concerns about what goes into cardboard - but I worry about everything too much. As long as it’s brown, not covered in ink and plastic, I’m sure it’s fine. I do use cardboard like this myself.

I add cardboard (plain brown, not coated, glued or covered with plastic film) to my composts all the time. I let the cardboard soak in water and then tear it into pieces when it is nice and soft. The resident compost worms love it. I would not compost anything that is glossy. Sometimes, I even add shredded office paper to my composts. The ink used in ordinary office or home printers is fine with composts.

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I’m a MASSIVE fan of Charles Dowding’s No Dig method, and he uses cardboard a lot - both in compost heaps and when initially creating a No Dig bed as the first layer. He is asked this question a lot, and is clear that using cardboard isn’t harmful to the soil once all tape etc. is removed.

Don’t put tumble dryer lint in your compost. Human and pet hair is fine though, if you fancy scooping that out of the vaccum!

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Thank you to everyone who replied.
Much appreciated.