Some plants propagate successfully by inserting mature stems in sharp sand in the ground or a bucket - this is referred to as hardwood cuttings. Others multiply if you divide root sections and partly bury in compost until new shoots form - this is called root cuttings.

Most cuttings need a well-aerated compost to keep them alive until new roots form. Some plants, e.g. streptocarpus, will root by slicing a leaf and inserting it edge-on in compost. Others form roots when the cuttings are placed in water - fuchsias for example.

There are also simpler methods to increase your plants. Splitting, or division, involves separating already-rooted stems.

Layering is also easy: just partly cut through and bury part of a stem to encourage it to form its own roots. When rooted, detach from the parent plant.

Plants often grow and root quicker in gentle heat - a heated propagator is extremely useful. See Greenhouse Gardening for more tips.