Overview
Liquid fertilisers are a great way to nourish your plants, providing nutrients in a readily available form, so they're quickly absorbed. There are many chemical fertilisers that will do the job but, by making your own using comfrey leaves, you'll have a steady supply of organic, nutrient-rich feed at little or no cost.
Deep-rooted comfrey can extract large quantities of nutrients from far below the soil's surface, inaccessible to other plants. These nutrients are stored in the leaves. Gardeners can access these nutrients by harvesting the leaves and letting them break down to release a rich, dark, nutrient-rich plant food.
How to do it
Adam's tip
You can also make a liquid feed using the leaves of bracken, clover, groundsel, nettles, borage, chicory and strawberries
http://www.gardenersworld.com/how-to/projects/basics/how-to-make-a-comfrey-feed/200.html