How much compost/manure to use
Postby charlesdowding » Sun Jul 26, 2009 11:46 am
Vegetables are hungry plants, also their growing involves periods of time when soil is bare, unless you are brilliant with green manures or permacultural combinations and can deal with the various issues they bring up such as cultivation and slugs.
My experience suggest that a dose of 3-5cm annually (1-2″) of reasonable quality compost or composted manure is sufficient to maintain soil in a fertile state. If it is poor to begin with, which includes too sandy or badly drained or low in organic matter, an initial larger dressing of up to 15cm (6″) will really pay off for many years.
Once you have applied compost, worms and other soil life begin to multiply and re-invigorate the existing soil, so it is not only about the nutrients you are adding with compost. Drainage will improve and weeds will be less numerous, mainly because a lot of their seeds are now buried. Keep weeding nonetheless to ensure the soil stays clean.
After the initial large application, you can run a fruit and vegetable plot on its maintenance dose, preferably applied as a surface mulch in autumn or winter as crops finish. Soil is thus always protected by either organic matter on top, and/or by growing crops. It enjoys that!
Also, and contrary to what is often said, nutrients in compost are mostly stable and become available to plants as roots demand them. They do not leach like soluble artificial fertiliser, hence you can apply compost or composted manure at any time of year, and look on it as soil food rather than plant food.
