"Roger Mills" wrote in message
...
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!

Beware also of soil getting into the gravel, above the still-intact weed
membrane, allowing weeds to grow *above* the membrane.

Our house has a *lot* of fairly deep 1/2" gravel for the drive, and it is
covered in weeds. We've tried hoeing them off, and when I've pulled up
weeds, they have had very shallow roots embedded in the gravel but not going
through the membrane to the soil underneath. The gravel is a confounded
nuisance, because it makes it *very* difficult to wheel the garden-waste bin
to the garden where it is needed, and likewise for the lawn mower. Both
start to dig into the gravel almost as soon as they go from paving
stones/tarmac onto the gravel, and quickly end up buried up to their axles
in gravel.