First, don't Google this unless you want to make marijuana tea. It took a little extra effort to find good directions on how to do this. These directions come from Farmer D. You do have to have a container with a top to cover your weed tea with, as it gets, ahem, aromatic, and it takes 3 weeks to make a batch.
What follows is a cut and paste from Farmer D. See the link for the rest of the directions, as per DU policy I can only cut and paste so much:
Continue good garden housekeeping by making compost tea from weeds pulled from your garden! Just like their tenacious ability to pop up in all areas of your garden, weeds' tenacity extends to nutrient uptake as well. Weeds compete with desirable plants for nutrients from your garden soil, and they are very good at it. Because of this, weeds are full of mineral nutrients. You can give back what weeds rob from your precious garden plants by making "weed tea" from the weeds you pull from the garden. Apply the nutrient rich concoction to your garden veggies and watch them flourish because one plant's trash is another plant's treasure!
Step 1: Weed your garden.
Step 2: Collect weeds and put them in a permeable bag such as a Hessian sack, onion or muslin bag, etc. Tightly tie off the sack-o-weeds.
Step 3: Find a bucket or container to fill with water. The ratio should be 1 part weeds to 10 parts water (25 liter container, 2.5 liter weed sack). Make sure your container has a tight fitting lid to keep the insects and fermenting odor away.
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This is an amazing way to create something positive out of something seemingly negative by closing the loop on weeds. Now that's biodynamic!

Cher