Something else we started growing in the 1970’s!  Much has been written about comfrey over the years (and centuries!) - possible medicinal uses, livestock feed, scares about a poisonous alkaloid, and so on.  
Simple Garden Uses
Tomato feed  Comfrey foliage rots down to make a very good liquid feed for tomatoes and anything else that likes a high-nitrogen, high-potassium feed.  There are two main techniques, both are a bit smelly, but the end result is very effective and has helped us grow some really tasty tomatoes over the years.  Basically, you can let the leaves rot down on their own, which produces a very concentrated liquid feed (dilute it 1:10), or you can rot them down in water, which produces a ready-to-use solution.  Obviously, you need a water butt or something similar.  (Cut nettles are quite effective too, and we have had good results.)  Interesting comfrey notes on the web
Instant Compost’  Comfrey leaves are apparently so well-balanced in plant foods, especially their carbon-to-nitrogen ratio, that you can use them like instant compost.  A classic example is to lay comfrey foliage in the bottom of potato trenches.  You can dig them into the ground with no fear of the usual ‘nitrogen robbery’ when fresh plant matter rots down in the soil.  
Animal and Poultry Feed  Perhaps not a real ‘garden’ use, but some pet animals like rabbits and guinea pigs seem to benefit from some comfrey leaves in their diet.  Chickens and geese apparently like it, and we used to feed it to our goats, who relished it.  After that, pigs, sheep, cows and horses - worth a try?  If you would like more information, please ask.  
Grow Your Own  We sometimes have some surplus comfrey plants, or can take root cuttings (better for posting) if you are interested to try growing comfrey yourself.  We normally sell these when we have them available, which is usually from Spring onwards – watch this space!
The Comfrey Page
Dave and Val Taylor
Wilanson, Blackberry Lane, Lapford, Devon, EX17 6LY  Tel:  07792 592068
blackberrylane.co.uk@gmail.com   http://www.blackberrylane.co.uk      See ‘What’s New?’ Page for more contact details
The Blackberry Lane Blog             @Blackberry_Lane