The No-Dig Method

No Dig method of cultivation can be used for two purposes: to provide a rich soil to grow in, and to clear a weed-infested growing area. Both instances require a great deal of surface mulch (well-rotted manure or compost). In principle, by avoiding digging you will not be disrupting the soil life, nor will you be exposing the soil to weed seeds. Instead the existing weeds are in darkness, which causes them to weaken and die.
For soil that is already cultivated, here's how :
  1. Apply at least 15 cms or more of an organic, well decomposed mulch to your beds. You don’t need to dig beforehand, as soil organisms such as worms will rise to the mulch, eat and digest it, creating a rich and well textured soil.
  2. You can plant or sow direct into the surface compost of newly-created beds, just as you would normally. You will find there are less weeds to hoe, they are easy to deal with in the soft surface, and the soil beneath is firm but not compacted, as the undisturbed soil organisms develop a honeycomb of small air passages – perfect for plant root penetration. To sow seeds, use a rake to prepare a soft, crumbly tilth on the surface.
  3. Use a trowel to remove any weed regrowth through mulches. Annual weeds will die within 2 to 3 months; but perennials take longer – often up to a year. Only bindweed and marestail can survive, but they become noticeably weaker. And as the soil becomes more friable and richer, it is easier to pull out the long root systems in bindweed, for instance.
  4. Ongoing maintenance involves annual applications of just 5 cms or so of compost or manure. This should be applied ideally in the autumn, when crops are cleared, or in spring on beds where winter crops have been growing.
To clear a growing area of weeds
The aim here is similar - to exclude the light so weeds can't grow. You can either use a sheet covering the soil or a thick, deep layer of mulch.
For the sheet covering, use thick layers of cardboard weighted down (which will degrade into the soil), or a thick membrane such as Mypex (which can be reused). We don't recommend plastic unless it can be reused and won't degrade into the soil; and we advise you to be wary of carpet as some dyes and mothproofing chemicals can be toxic.
If you don't have a suitable sheet covering, then a deep layer of mulch does just as well in excluding the light and suppressing weeds. Use homemade compost, fully-rotted manure, leaves, straw, grass mowings – or even a mix of them all, so long as it is more than 15 cms thick. Eventually it will rot down and create a wonderful, friable soil texture which is not only rich but allows weed roots, such as bindweed, to be pulled out easily.
Both methods will make sure that absolutely no light can penetrate down into the soil. Be patient! It can take up to a year to completely weaken the weeds, especially those with deep and extensive roots like bindweed, dock and bramble.
If you are clearing a large area, such as an allotment, see  Organic Allotment Growing.