Grow Comfrey 'Bocking 14'

If I have 10 plants of these, would it provide enough feritliser for my half plot?

I wonder if I plant them in my plot, will they drain all the nutritions from the soil? or does comfrey absorb NPK from air under sunshine? I don't want to let comfrey get it all from soil and then I have to compost them and give back to vegitables...If you know what I mean?

Thanks for any advice.

by the way these were said on thompson-morgan website

   
Comfrey 'Bocking 14'
Symphytum x uplandicum 'Bocking 14', Russian Comfrey
Hardy Perennial

Grow your own soil conditioner! Comfrey ‘Bocking 14’ contains high levels of basic NPK nutrients and because it is a sterile hybrid, it won’t self seed all over your garden.

The nutrient rich foliage of comfrey can be used as a compost activator, mulch, or soaked in barrels of water for 3 to 5 weeks to make a useful liquid feed for tomatoes and beans. Scatter the wilted leaves throughout potato trenches just before planting, to fertilise the crop and improve their flavour! Once established, this quick growing plant can be cut 3 or 4 times throughout the growing season, for a constant supply of nutrient rich, organic, comfrey fertiliser. Height: 100cm (40”). Spread: 75cm (30”).

Flowering Period:    May, June, July, August

Position:    sun or semi shade

This article should answer most of your questions:

http://www.allotment-garden.org/vegetable/comfrey/index.php

Thanks for the link.

I read it and googled other info, I found it is hard to tell how many comfrey plants are needed to feed half plot, as it is difficult to tell how well the plants grow. Comfrey, like any other plants, needs NPK to grow and it can only get them from soil. In another word, you need to feed comfrey plants for them to produce what you need. And I am asking myself, why not feed the vegitables directly?

the reason are,

1. comfrey's root goes very deep and get nutritions others couldn't?
2. comfrey leaf decomposes fast than most others?

HI,

Sorry to hijack the thread, i had some comfrey seeds turn up on my door step a few days ago, was going to plant up the allotment this weekend in an old bath tub. I have read on here about I should use Bocking 14, is this because you don't get seeds from it?  I would like to carry on with my original idea with the bath tub but don't want to go spreading it on to other plots (seeds drifting in the wind).

If this is the case would covering over the bed with fine enviromesh or plastic help stop the spreading?

Thanks Dan

ok thanks