[Growster...]

Somehow, brown cardboard always seems to be acceptable doesn't it!

Those bright vivid green boxes for veg from 'somewhere or other' just look a bit suspect - especially if you're trying to create a plot where you are happy with what's providing the weed suppressant!

[Madame Cholet]

thats good to know vegetable dyes i guess

[angelavdavis]

Chemicals in printing ink are safe to compost these days and therefore safe to use on the plot.

Yep very comforting to know.  I had wondered about white cardboard and what bleaching agents (if any) were being used to be honest. Well, just applied another batch onto a new lasagne bed, so here's hoping!