Editing Weed control (section)

==== Coverings ====
In a domestic gardens, methods of weed control include covering an area of ground with a material that creates an unsuitable environment for weed growth, known as a ''weed mat''. For example, several layers of wet [[newspaper]] prevent light from reaching plants beneath, which kills them.

In the case of black plastic, the [[greenhouse effect]] kills the plants. Although the black plastic sheet is effective at preventing weeds that it covers, it is difficult to achieve complete coverage. Eradicating persistent perennials may require the sheets to be left in place for at least two seasons.{{Citation needed|date=September 2022}}

Some plants are said to produce root exudates that suppress [[herb]]aceous weeds. ''[[Tagetes minuta]]'' is claimed to be effective against couch and ground elder,<ref>{{cite web|url=http://www.pfaf.org/user/Plant.aspx?LatinName=Tagetes+minuta|title=Tagetes minuta Muster-John-Henry PFAF Plant Database|work=pfaf.org}}</ref> whilst a border of [[comfrey]] is also said to act as a barrier against the invasion of some weeds including couch.
A {{convert|5|–|10|cm}} layer of [[Woodchips|wood chip]] [[mulch]] prevents some weeds from sprouting.

[[Gravel]] can serve as an inorganic mulch.

[[Irrigation]] is sometimes used as a weed control measure such as in the case of [[paddy fields]] to kill any plant other than the water-tolerant rice crop.