When I lay down newspapers to smother weeds and build a new garden bed, is there any danger of the newspaper inks leaching into the soil and being toxic?
Today’s newspaper ink is largely based on soybean oil. It has been on the newspaper market since 1989. You might have noticed if your hands are moist when reading the paper that the ink more readily smudges. If you have any questions about the particular newspaper you are using, call them and ask what kind of ink they use.
It is preferable to use only the black and white newsprint for smothering weeds or grass to create a new garden bed. Some of the older colored inks contained petroleum-based solvents or oils with pigments containing toxic substances. Although, with society’s emphasis on recycling, most newspapers are now using vegetable dyes even for colored advertisements and the comics. Again, check with your newspaper of choice.
Any glossy pages, however, are covered with a clay coating that retards decomposition. So do NOT use or compost with any of the advertising inserts. These ad inserts are printed by someone other than the newspaper and can contain the heavy metal inks toxic to microorganisms.
If you are preparing a vegetable bed, you might feel safer cultivating the weeds and soil manually. However, the soy-ink newspaper smother is still one of the fastest ways to make a new bed ready for the eager home gardener.