I started using comfrey leaves and making my tea purely by what made sense to me and I later started to research methods after the event and mine is slightly different to the main recipe on the internet which seems to me to be shove about a whole comfrey plant worth of leaves in a bucket, weigh down with a brick and add water. Wait for 4 weeks. Then dilute 1 part to 9 parts in your watering can. Add feed to plants that need lots of potash and nitrogen.
However, as usual, I didn't research the method at all before starting. I had my bucket and I added a generous handful of comfrey leaves and filled the bucket. I waited about a week or so and the top of the water in the bucket was looking a little metallic, presumably from the nutrients from the leaves. I started using a cheeky bit from the bucket at this early stage. The water was clear but it seemed to be having an effect with only this small amount of time. Mark Ridsdill Smith http://www.verticalveg.org.uk/ was right - its strong stuff!
Each week, I added a generous handful of leaves and the solution got stronger and stronger as the weeks progressed.
I now have the habit of feeding the whole garden with 1 part comfrey tea and 9 parts water in my watering can. I then add a big handful of comfrey leaves and add water (rain water if I have it available). Let it stew for a week and then use it to feed the garden again.
It's really strong stuff and I'm starting to see some really gutsy plants - especially rhubarb which has done a summer sprout of new leaf and the pumpkins.
Please be warned that some people find the smell a bit repulsive. It doesn't bother me all that much but when it's really ripe and full of nutrients, it smells a bit like something's died in it. A good location to keep your bucket is the far end of the garden (as far away from your house as possible). When I feed the plants, I never notice the smell near the plants.
Comfrey contains potash which is great for your flowering plants, fruiting plants and it also has nitrogen too for your leafy vegetables, so I pretty much give it to everything.
I grow comfrey in the garden but I prefer to use foraged comfrey leaves as I believe the plants in the wild have found a place with their favourite nutrients and these might not necessarily be in such large supply in my garden's soil. However, it's great having a backup source in the garden just in case I forget to go foraging on the way home from work.
I'm now considering making tea out of those tough perrenial weeds that you don't want to add to your compost.
How do you make yours?