I have been asked by my children's school to make a frame to contain soil/compost type material for planting bulbs in. It is quite a large triangular area and I was thinking of making it from decking planking etc. The total height will be "3 bricks" i.e. approx 9 inches. I will stake it every so often for strength but my main concern is will it last. I don't think the school want a hundred years out of it but would like it to last a while. Is the decking planking treated to withstand this or will I need to do something else to it, I don't really want to start lining it with any thing as I am providing all the materials and labour for free so the cheaper and quicker the better as far as I am concerned. Also if anybody in the Leeds/Wakefield area has any decking planks left over from a project, would you consider donating them to a good cause?
Cheers
John