First off, you are not alone! Lots of people who propagate cuttings do not always see root development because of a few small errors they make. Below are the most common reasons why cuttings do not successfully start rooting:

• Not stripping the leaves low enough on the cutting (where the roots emerge from)
• Not stripping enough leaves from cutting; leaves transpire water which can cause the cutting to lose turgidity (wilt) and possibly die.
• Not taking proper care of the unrooted cutting before planting it; Cuttings should be stuck in their propagation medium as soon as they arrive, but if this is not possible, store them cool, respecting temperature minimums for cold intolerant plants.
• Too little space between cuttings; if the cuttings are planted too close together there can be increased loss from bacterial disease and often flowering is delayed in liners by a few days.
• Incorrect growing medium; a good growing medium should have both good water holding capacity and high air porosity. Ideally, the growing medium should have peat to retain water and aggregate such as perlite or vermiculite to increase air porosity.
• Not adjusting misting/fogging to work with the selected growing medium; if too much application of mist/fog keeps the growing medium saturated, excess water will flow from the bottom of the trays and rooting will be delayed. Applying too little mist/fog will increase transpiration from the leaves, cuttings will lose turgidity and could die from drying out.
• Incorrect growing medium temperatures; To improve success with rooting of cuttings it is best to maintain growing medium temperatures between 20-25°C; even cold tolerant crops such as pansy, dianthus, osteospermum, petunia, etc. prefer these medium temperatures for rooting. Warm growing medium temperatures accelerate cell division which leads to faster callusing, root initial development and subsequent root growth.
• Incorrect light exposure; During the winter in northern climates, most plant cultivars would benefit from supplemental lighting. Research has shown that light speeds up the rooting process and the liners can finish up to 10-14 days faster. In the summer, especially in southern climates, high light can damage cuttings mostly from excess transpiration of water through the leaves or also through heat build up. Cuttings should be shaded to slow transpiration and keep them cool.
• Air temperature is not as important for rooting, but it is suggested that it should be set between 19-24°C. Air temperature becomes important when new shoot growth begins; in that, warmer temperatures encourage faster top growth.

It’s recommended to preferably utilise a mixture of peat and sand, that has been be well-drained. Keep the medium moist, but please note not to over water the medium. Keep the cuttings away from full sunlight. Should there be no shade, use a piece of shade netting.

Once the cutting has a substantial amount of roots, carefully lift the cutting out of the container, to be transplanted in a suitable well drained soil medium, without damaging the new roots.

The best time to make cuttings is just after Spring when new shoots are strong enough to be cut for propagation. If heating is available, cuttings can be made right through the year.