Comfrey is such a deep rooted plant that it grows quick and fast, even when it's still early in the growing season. My own Comfrey is now ready for the chop, first 2014 batch of pure organic plant food coming up in 6 weeks..
See here for Using and Making Comfrey Fertiliser
Gardening on Radio Foyle
A summary of each weeks gardening on Mark Patterson Show and beyond