Happy New Year from the US

The future bog garden. The bed has a boulder on the tree stump and the rainwater duct can be seen on the left and comes from the downpipe at the back corner of the house - behind the bed.

I understand from the news online that things have got rather cold at home.  Perhaps that is a good thing as I certainly had a major infestation with whitefly which I hope will be killed off by the cold.  They even resisted when I was forced to use soap and water sprays - and eventually I was reduced to using contact insecticide (Pyrethrum, I think) but still to little effect.
Here, however, in the American mid-West the weather is seriously cold.  Yesterday the top temperature was about minus 5 degrees Centigrade.  I am rather disappointed, however, as I had expected to be enjoying the snow but all I have seen is the old snow heaped in corners out of the sun.  Not to say that wrapping up warm is the order of the day.  Even a slight breeze cuts right through you.
The only gardening I have managed to do was in the first week when it was still above freezing and that was only to run the mower over the grass to pick up the dead leaves.

My son hopes to use some of the 33" of rain that falls here (Christchurch only gets 23") to make a bog garden.  I have given him the benefit of my very limited knowledge so I anyone out there has experience of building a bog garden I would be grateful for comments.  They have already got, as is normal here, long 5" flexible pipes leading the rainwater from the roof 4/5 yards from the house.  He plans to direct 1/4 of the water from his roof into a bed that, when the old tree stump is removed, will have a small depression in it.  The soil is a clay loam and the site slopes to the south east and is sheltered from the south east by the roadside trees.

He also plans to grow vegetables in raised beds at the back of his 'yard' ('garden' to you and me).  He is concerned about the wood treatment chemicals leaching into the soil.  Has anyone dealt with this problem or should he use the artificial wood decking that is available here?  I think it is plastic but may be reconstituted wood.

Happy New Year to you all!

---