Tuesday 5 February 2013

layering mulch to suppress weeds without weedkillers

Our long drive has been infested with nettles and brambles for many years. We have laid the base coat of hardcore for the drive and are getting ready to create a beautiful drive side border to welcome family and friends to Cordwood.

We do not want to use any weedkillers. Indeed, latest research shows that glyphosate weedkiller causes deformities in frogs. How many years before this is banned??
Our challenge is to 'clean' this land in readiness for planting organically: but we don't have the time for conventional hand weeding...

Our answer is to mulch the ground with organic material.
cardboard; straw; cardboard; chippings
  • So, first a good layer of cardboard in two or three sheets of thickness. Newspaper in sufficient thickness can go in as the base layer if you have plenty of this to hand. By using newspaper as the first layer, there aren't the problems you may get with it being blown around when used nearer the top of the mulch.
  • Next, a 10 cm layer of organic material. This time we used straw, but this could be hay, compost, lawn cuttings, manure, leaves, bracken or chippings - whatever is at hand. Weed seeds contained within this layer should remain dormant as this method denies them access to light - but, of course, don't add anything with roots....
  • Then another thick layer of cardboard.....
  • Before a final 10cm 'top coat' of chippings.
This thick 'lasagne' of organic layers is intended to be permeable, allowing moisture into the soil as the material degrades, but is to be thick enough to prevent light getting to the perennial weeds below. It is the deprival of light that should kill these perennial weeds.

The mulch is then left. As weeds die in the soil layer beneath, the top mulch should slowly become incorporated into the soil, making an excellent growing medium.

Although this method saves the work of weeding, it is heavily dependent upon having enough material to create the layers. All cardboard donations gratefully received!!!

We will review its progress but hope to plant into it in the autumn.




3 comments:

Ken said...

Perennial weeds are such a pain! Do you know a good way to get rid of them without using poisonous spray? For things like this: Gardening

Rob said...

Nothing really beats digging out those perennial weed roots Ken.

Joe Farinaccio said...

Using an organic mulch in this way should work. I remember a book that was published about a decade ago entitled, Lasagna Gardening. The concept worked very muck like this, involving layers of organic material placed throughout the desired plants within a vegetable garden. There was a lot of evidence this method kept weeds at bay.