I've had a worm bin about 3 months now, and I love it. I use the worm tea fairly regularly - I have so much I even give it away!

But, I remember in my vermicomposting class that the instructor said that worm tea could also be used to kill plants. That if we let it go flat or dead, it's the most effective herbicide out there.

I have a plant I want to kill. I don't know what this plant is; it's grown up out of a crack in our dog run. I pulled it several times, but it just keeps coming back. It's a rather ugly thing with black berries and thorns; I got one of the thorns stuck in me and got really sick, so I want this thing gone before we start putting our dogs out there again.

How do I turn my worm tea into an herbicide? How will I know if it's anerobic and will kill?