Posted: 07/09/2013 at 12:43
sodium hydroxide or caustic soda would kill all remaining weed seeds and any viable roots but as I cannot buy it I want to use something to ensure a belt and braces job.
I am happy with my planting scheme, having purchased the planters and the plants already. Phormiums were chosen as the site is very, very hot and closed on two sides by one, the house with white walls and secondly by a white wall one and a half metres high beside the swimming pool. the site is otherwise closed by a concrete. and stone patio. It is some distance from any other planting and so I am not concerned about anything leeching from the site.
The weed blanket i have bought is dense and of good quality, it will be doubled in several places.
It seems as if the advice is not to bother with any additional soil treatment