Coloured Cardboard

[Macy]

There's a few printer and paper boxes knocking around work, which I was going to recycle as a mulch and as cabbage collars. However, they are printed/ colour - some where in my head I have the notion that these are are safe to use, as the ink used these days is plant based - is that correct? Or should I let them disappear into the recycling skip.

[Macy]

[manicscousers]

Hiya, macy, hope you get a positive answer, we compost all our cardboard including cereal packets and they're full of colour  ;D

[Pesky Wabbit]

All coloured newspaper, packaging use vegetable dyes these days and are perfectly safe to compost, use as collars etc.

[Macy]

Thanks guys, now for watching my colleagues eyes glaze over when they ask why I'm taking it!  ;D

[Ian Pearson]

Yes, safe if printed in the EEC or North America. I'd be cautious of anything printed in the far east tho', as I believe they have less rigorous standards.
Quote from Wikipedia on ink "Standards for the amount of heavy metals in ink have been set by some regulatory bodies"
(The underlining is mine)
The trouble with composting is that it tends to concentrate pollutants.

[Ian Pearson]

Okay, I knew I had something in a book about this ... just found it.
From Patrick Whitefield's 'The Earth Care Manual' pg 197 'Is paper mulch safe':
Firstly," the content of heavy metals in the (paper mill) sludge is lower than in most natural soils."
But
"paper mulch can depress plant growth on some soils" due to  aluminium added during the papermaking process which can " leach out of the mulch and make phosphorus less available in the soil. The researchers recommend avoiding large ammounts of newspaper around shallow rooted plants growing in acidic soils, that is those with a pH of less than 6."

he concludes" ...these findings do suggest that any product which has been through an industrial process must to some degree be suspect."

I'm not typing any more. go and buy your own book! :-)