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I'm interested in putting down raised beds this year, so I did a little research into pressure treated boards and the chemicals that are used in them.
Chromated copper arsenate (CCA) is the chemical that was used to treat boards in the past. The aresenate part of this chemical can leach arsenic into the surrounding soil. Whether the amount in negligible or not is an open question. Most articles I read said that plants would die and not grow before the amount of arsenic became a health issue for people.
However, it doesn't matter. CCA was taken out of circulation 6 years ago and banned 5 years ago.
Pressure treated boards nowadays are treated with chemical mixes that do not include arsenic. I contacted Homebase and was told by their buying department that their products are treated with Tanalith E.
Another chemical that might be used is alkaline copper quat (ACQ). Again, there is no arsenic in this mix.
As pressure treated boards tend to be much cheaper than the other options of hard-wearing oak, cedar or the like, I hope other gardeners out there will find it useful to know they are safe using this kind of timber for their raised beds.
Chromated copper arsenate (CCA) is the chemical that was used to treat boards in the past. The aresenate part of this chemical can leach arsenic into the surrounding soil. Whether the amount in negligible or not is an open question. Most articles I read said that plants would die and not grow before the amount of arsenic became a health issue for people.
However, it doesn't matter. CCA was taken out of circulation 6 years ago and banned 5 years ago.
Pressure treated boards nowadays are treated with chemical mixes that do not include arsenic. I contacted Homebase and was told by their buying department that their products are treated with Tanalith E.
Another chemical that might be used is alkaline copper quat (ACQ). Again, there is no arsenic in this mix.
As pressure treated boards tend to be much cheaper than the other options of hard-wearing oak, cedar or the like, I hope other gardeners out there will find it useful to know they are safe using this kind of timber for their raised beds.
