In the garden, mulches are used to improve plant growth. They regulate soil temperature by keeping plant roots warm in winter and cool in summer, they reduce water loss from the soil surface around the plants and they help to discourage weed seeds from germinating by preventing light from reaching them. This is done with organic and inorganic mulches. The mulch should be spread around a small or medium-sized plant to the full extent of the foliage canopy.
Before applying mulches around the plants make sure you remove all perennial weeds, else the weeds will benefit from the mulch effect to the detriment of your plants. Also do not apply mulch when the soil is cold or frozen because the insulation effect will work in the wrong way keeping the soil cold instead of keeping it warm. Wait until the soil has warmed up in spring and then apply the mulch.
When using organic mulches make sure that the mulch is long-lasting and not easily dislodged by rain in order to be effective. Also it should have a loose structure to allow water to pass through it quickly. One of the most effective organic mulch is the coarse bark because it inhibits weed seeds from germinating and if any weed appears it can be removed easily. Other organic mulches, like garden compost, leaf mould and peat substitute are also good but not effective in discouraging weeds because they provide an ideal medium for weed seeds germination and are quickly mixed into the soil, but they do improve the soil texture as a result.
Inorganic mulches made from biodegradable horticultural paper or thin sheets of woven or bonded, water-permeable fabrics are easy to lay and to plant through and provide good weed suppression while allowing water to pass through it to plant roots. A disadvantage of these mulches is that once they are in place you cannot add any organic matter to the plants, so make sure you incorporate in soil sufficient organic matter before laying the sheet mulches.
Another type of inorganic mulch is the impermeable plastic sheet. They are particularly useful when laid temporarily to warm the soil in spring to allow early sowings or longer-term for perennial weed suppression. A disadvantage of this mulch is that they do not allow water to evaporate from soil and because of this they are not suitable for waterlogged soils.
You can also increase soil temperature by using floating mulches. They are sheets of light perforated plastic or fibre fleece used like cloches. As the crop grows the floating mulch is raised by the plants. They also act as a barrier against pests.