If the plant is unlikely to grow then a rooting hormone to “encourage” the plant to grow and mature may be administered. Though not essential, several compounds may be used to promote the formation of roots through the signaling activity of plant hormone auxins, and is helpful with especially hard plant species. Among the commonly used chemicals is indole-3-butyric acid (IBA) used as a powder, liquid solution or gel. This compound is applied either to the cut tip of the cutting or as a foliar spray. Rooting hormone can be manufactured naturally – one method is to soak the yellow-tipped shoots of a weeping willow tree in water, or to prepare a tea from the bark of a willow tree. When using the shoots or bark, they should be soaked for 24 hours prior to using.  Honey, though it does not contain any plant hormones, can also make an effective rooting substance. [ citation needed ]
- Stem cuttings, in which a piece of stem is part buried in the soil, including at least one leaf node. The cutting is able to produce new roots, usually at the node.
- Root cuttings, in which a section of root is buried just below the soil surface, and produces new shoots
- Scion cuttings, which are dormant ligneous woody twigs. 
- Eye cuttings, which are pieces of foliated or defoliated stalks with one or more eyes. 
- Leaf cuttings, in which a leaf is placed on moist soil. These have to develop both new stems and new roots. Some leaves will produce one plant at the base of the leaf. In some species, multiple new plants can be produced at many places on one leaf, and these can be induced by cutting the leaf veins.
There are ways of improving the growth of stem cutting propagations. Intensifying light allows cuttings to root and sprout faster, apart from the concern that this could cause the propagation material distress.  Azalea cuttings can be mildly heated in water to disinfect it from the fungus pathogen Rhizoctonia, and this could potentially be used for other plants. 
Plant cutting, also known as striking or cloning, is a technique for vegetatively (asexually) propagating plants in which a piece of the stem or root of the source plant is placed in a suitable medium such as moist soil, potting mix, coir or rock wool. The cutting produces new roots, stems, or both, and thus becomes a new plant independent of the parent.
Some plants form roots much more easily. Most succulent cuttings can be left on a table and small roots will form, and some other plants can form roots from having their cuttings placed in a cup of water.
Typically, striking is a simple process in which a small amount of the parent plant is removed. This removed piece, called the cutting, is then encouraged to grow as an independent plant.
Although some species, such as willow, blackberry and pelargoniums can be grown simply by placing a cutting into moist ground, the majority of species require more attention. Most species require humid, warm, partially shaded conditions to strike, thus requiring the approach above to be followed. Particularly difficult species may need cool air above and warm soil. In addition, with many more difficult cuttings, one should use the type of cutting that has the most chance of success with that particular plant species. 
In addition, the cutting needs to be taken correctly. It must be taken at the right time; in temperate countries, stem cuttings of young wood need to be taken in spring, of hardened wood they need to be taken in winter. It must have the right size and amount of foliage; length of stem cuttings of soft wood for example need to be between 5–15 cm and of hard wood between 20–25 cm. Also, two thirds of the foliage of soft wood stem cuttings should be removed. For hard wood stem cuttings, complete foliage removal is necessary.
- chalk; to increase the pH-value of the soil; a pH of 6-6.5 is to be maintained
- organic substance/humus; to increase nutrient load; keep to a bare minimum though
- sand or gravel; to increase the soil’s water permeability
Plant propagation/Cloning Plant cutting , also known as striking or cloning , is a technique for vegetatively (asexually) propagating plants in which a piece of the stem or root of the
However, cutting the middle can be equally effective, especially if the plant you’re working with is showing new leaf buds along the stem. Cutting directly above those baby leaves will actually produce two separate shoots when the plant begins to regrow as a clone. This is a great option if you’re looking to grow a bushier plant.
After you’ve clipped the cutting from your mature plant, you need to cut all the fully-developed leaves and the stem at an angle.
In order to clone your plant successfully, you need:
Regardless of which option you choose, you want to work with a plant that has a thick and sturdy stem. The section you choose (middle or tip) should also have four visible leaves. Being selective in this way will give your clones the best chance: propagation is an energetically expensive process, so starting with a hearty plant increases the likelihood of success.
A healthy plant that you want to clone
Herb clones traditionally perform really well– some varieties to try include thyme, sage, basil, and mint (the subject of our video!). While you can theoretically clone any plant, the main school of thought is that plants with sturdier/thicker stems (like a tomato plant) will be more successful while a stalk-less, flimsy, or soft plant (like lettuce) will not clone well at all.
Empty seedling trays and enough grow plugs
Just like with typical seedlings, the clones will need to be covered with a humidity dome. However, unlike plants growing from seeds, they will need access to water the whole time, so you will keep your normal watering schedule. Another difference is that seedlings growing from seed typically stay in the nursery station for three weeks, while the clones will take a little bit longer. At three weeks, the clones finish developing their new root structure, so they need another 1-2 weeks to grow their stems and leaves before moving to the cultivation area.
With cloning, what matters most is cutting from the right part of the plant. You can choose to cut the tip of the stem or the middle of the stem. If you’re not sure, we recommend cutting the tip of the stem since that’s where most of the plant growth is happening already.
Cloning might sound like a complicated process, but it’s actually quite simple. Our expert hydroponic farmer explains what plant cloning is and how to clone any plant in four easy steps.