Question
Last year I pickled about 20kg of garden weeds (dock, dandelion, thistle,
nutgrass, canola, ryegrass) in a drum of water and used the mixture as a
fertilizer.
Without knowing what the brew contained, it certainly increased micro-
activity in the soil and gave the vegetables a growth boost.
I also noticed that cuts and abrasions healed much faster after I washed my
hands in this mixture.
Could you give me some idea of what elements and nutrients my homemade
fertilizer contains?

Answer
Spooky experience you have described, Jed, because your Brew most likely was dominated by anaerobic bacteria if it was not aerated almost constantly.

The list of Anaerobes is most distinguished for its pathogens.  Disease causing bacteria don't like Oxygen.  You could have given yourself some dreadful afflictions.  Instead, you observe quicker healing and growth spurts in your plants.

If you actually pickled your Weeds with a recipe that included Vinegar and/or (perhaps) Sugar, that would be a different story.  Let me know if you actually did something like this.  We have to talk.

It is conceivable that one or more of the materials you included in your brew released a chemical that has unexpected side effects.  Other than that, doses of Nitrogen, Phosphorus, Potassium and miscellaneous nutrients along with the aforementioned bacteria, equivalent to CO2-rich Compost Tea would be in there.  Compost Tea is a centuries old soil enricher that incorporates a sort of antibodies defense in the Soil -- for plants.  Not for people.

Consider this: Dormant spores of Clostridium tetani (the bacteria that cause Lockjaw) occur abundantly in Soil everywhere.  One person in 3 die without treatment.  You get infected almost always by introducing the bacteria to an open wound or cut.  And that's just C. tetani.  Don't wash your hands with Pickled Weeds.  You're asking for trouble.  Watering your plants with them, however, may be beneficial -- just monitor the response to make sure you have enough helpful bacteria in there.  Aerating will eliminate the anaerobes and produce even better Compost Tea.  Which is MUCH better than anything you can buy at the garden center that was made and packaged in a factory somewhere.  Nice work.