Quick mulches - Old compost, coarse compost, strawy manure -Can be intended to break down and become Humus over a season. Slow breakdown mulches, Bark, wood shaving, shredded paper, will break down slowly – several seasons but used mostly for annual weed control and prevention of capping of soils. As they break down they will use nitrogen in decay process so reduce fertility temporarily.
Mulching (materials laid over the soil): Conserves moisture; Supresses annual weeds; Provides plant food; Looks nice; Best applied when the soil is moist and warm, usually early April.
Organic Materials: Ideally 10cm deep; Most organics like FYM and compost are good as they provide plant foods but only last a season, with the exception of bark chip which has no food but lasts up to 5 seasons.
Materials laid over the soil; Organic materials ideally 10cm deep; Conserves moisture; Suppresses annual weeds; Provides plant foods; Can look nice; Best applied when the soil is moist and warm, usually early April; Most organics like FYM and compost are good as they provide plant foods, but only last a season, although bark chip has no food but last up to 5 seasons.
Inorganic Alternatives: Polythene (black) needs to be UVI inhibited: Works well; Conserves moisture; Supresses annual weeds and perennials; Black warms the soil; Provides no plant foods; Does not look nice (can be used under a thin layer of nicer looking material such as bark/gravel or cocoa shell); Can puddle as water cannot go through; Holds soil very wet underneath so soil structure is damaged; Long lasting.
Woven Fibres: As polythene but draining and breathable.
Gravel: Looks better, but should be appropriate to surrounding stone. Needs to be thick to stop light going through and allowing weeds to germinate; Not good for small wheels (push chairs); Good over woven fibres; Long lasting.
Glass: As gravel; Brighter colours?? (graveyard look??).