Group,

After my last post I continued work on the raised beds I'm making for my
front garden. One particular piece of gravel board had many greenish
white spots of what I supposed was the chemical used for impregnating the
timber. The spots could be rubbed off with a wire brush. Around the
plank's knots the residue was quite green so I decided to find out what
happened when water was sprayed on the plank.

After spraying half the plank with a hose pipe the spots had turned more
green. Assessing the difference was not possible because the plank was wet.
I then poured about 2 pints of boiling water all along the six foot plank
and left it where the sun's heat could dry it.

It is now dry and there's still greenish white spots on it and the areas
round the knots are still green, ergo, I consider that the residues are not
readily soluble.

I realise that what I did cannot be called scientific in the present day's
meaning of the word and I no longer have the wherewithall to conduct
quantitive tests/measurements but science means truth and I assure you that
what I've written above is just that.

But if you are still worried, do not use gravel board. I have one raised 4
X 8 ft
bed constructed of concrete blocks which was a lot more expensive than
gravel board..

Regards

Ron