how does one stop weeds?

[Rod Serling]

We are removing the bark shavings from our garden's brick towers and troughs, which are filled with earth and covered in black gauze membrane to stop the weeds.

We want to replace the bark with decorative stones, and also replace the membrane with something else less unsightly.

Is there any other system (short of spraying Roundup all over the soil), that will prevent the weeds growing up through the stones in no time at all.

[Wispy68]

I heard on the radio the other day that human urine is an excellent weed killer and that many professional gardeners use it, but I don't know whether that would be your 'cup of tea'!

[Wispy68]

Salt or boiling water are supposed to be pretty good, too.