On Friday, 21 June 2019 10:16:07 UTC+1, Roger Mills wrote:
I have a patio area/path consisting of a couple of inches of pea gravel
on top of some weed matting.

When I first created this 20-odd years ago, I gave the soil a liberal
dose of sodium chlorate before laying the weed matting. This kept it
weed-free for quite a few years, but the matting has now deteriorated -
allowing a lot of weeds to take root.

I have removed the gravel and the weeds, and am about to take up the
matting and renew it before covering it with new gravel. I need to be
able to neutralise the soil in order to prevent any roots or seeds left
in from growing. I don't think you can buy sodium chlorate any more.
Most of the weedkillers available seem to be of the systemic type -
which kill existing weeds but don't affect the soil. But that's not what
I want!

Any bright ideas?


Salt. Almost as good as sodium chlorate.
Obtainable cheaply for de-icing driveways.
Or even free for the dishonest.

You must dissolve it (strong solution) and water the ground, don't throw it down dry. Ineffective if you don't.