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Plant cutting, also known as striking/cloning, is a technique for vegetatively (asexually) propagating plants in which a piece of the source plant containing at least one stem cell 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.
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Technique
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.
However, to have a fair degree of success, the practice of taking cuttings is not as straightforward/easy as it may appear. If strikings are taken without providing the right growing conditions, it is more likely than not that the cutting will not “catch on” (form roots).
Thus, to have a fair amount of cuttings catching on, the cutting should have:
- good, moist soil; that is soil that is light/airy and which contains sufficient nutrients
- a humid environment (this generally means placing the cuttings under a plastic sheet or in another confined space where through simple watering, the air can be kept humid/moist
- partial shade (to prevent the cutting from drying out)
After cuttings are placed in soil, they are watered thoroughly with a fine mist. The fine mist of a nozzle sprayer or a spray mist bottle are often used. After the initial watering, soil is allowed to almost dry out before misting again, with the aim to keep the soil moist but not wet and waterlogged. A fine mist is used to avoid disturbing plants.
In addition, the cutting needs to be taken correctly; this means:
- 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
- with the right size and amount of foliage; length of stem cuttings of soft wood for example need to be between 5-15cm and of hard wood between 20-25cm. Also, the foliage of soft wood stem cuttings needs to be removed by 2/3 and of hard wood stem cuttings, complete foliage removal is necessary.
Also, though not essential, several compounds may be used to promote the formation of roots such as the auxins. Among the commonly used ones is indole-3-butyric acid, or IBA, used as a powder, solution or gel. This compound is applied either to the cut tip of the cutting or as a foliar spray.
Types of cuttings
Many vegetative parts of a plant can be used. The most common methods are
- Stem cuttings, in which a piece of stem is part buried in the soil, including at least one leaf node. It produces 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.[2]
- Eye cuttings, which are pieces of foliated or defoliated stalks with one or more eyes.[3]
- 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.
Although some species, such as willow, blackberry and pelargoniums can be struck simply by sticking into moist ground, most 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 strikings, one would also prefer to use the type of cutting that has the most chance of success with that particular plant species.[4]
Providing the right soil
Depending on the type of soil with which you start, several additives may need adding to create good soil for cuttings. These additions may include :
- 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/gravel; to increase the soils water permeability
For example with plain potting soil, you would want to add 1/3 sand to make suitable soil for cuttings.
Providing the right humidity
Although several options can be used here, usually semi-white plastic is used to cover the cuttings. The soil below and from the cuttings themselves is kept moist. Aerate once in a while to prevent formation of molds.
Rooting substance
As mentioned before, rooting hormone may be used to facilitate striking, yet is generally not the most important factor in the process. However it is helpful with especially hard plant species.
Many root promoting products from various companies are offered on the market. Substances with rooting effects are almost inevitably based on signaling activity of plant hormone auxin and various auxin compounds (IAA, NAA, IBA, ..) were implemented in various commercially available products. If you do not want to buy similar product on market, you may try prepare some rooting substance in more traditional way.
Making your own rooting hormone
When starting a new plant from a leaf or stem cutting, the cutting will be more likely to form roots and create a new plant if a rooting hormone is used.
While commercial rooting hormone can be used there are organic homemade versions that work as well.
To make rooting hormone, soak the yellow-tipped shoots of a weeping willow tree in water. A tea made from the bark of a willow tree is also effective. When using the shoots or bark, soak them for 24 hours prior to using.[5]
Some people have found that using honey makes an effective rooting hormone as well.
Leaf cuttings: Any plant with leaves such as African Violet, Geranium etc. can be propagated with leaf cuttings. Using a sharp knife, cut off a healthy leaf at the point where it joins the stem. Insert the cut part, called a petiole, into the rooting hormone. Place the end into a small container of light potting soil in which you make a small hole with a pencil.
Making a hole prior to planting assures that the rooting hormone will not be brushed off the cutting when you plant it. Perlite, Vermiculite, and/or water-soaked Sphagnum moss can be added to potting soil to make the soil light. Make sure the leaf is leaning slightly so that the new plants will have plenty of light and not be shaded by the leaf.
Stem cuttings: These are treated just like leaf cuttings except you cut off a stem with several leaves instead of just one leaf. Remove the bottom leaves, leaving a few at the top. Proceed as with the leaf cutting.
In both instances, cover the pot with a plastic bag or inverted glass jar. This will keep moisture from evaporating and keep the cutting from wilting. Keep in a warm location with diffused light but out of direct sunlight. When there is indications of growth after about 3 to 6 weeks, transplant the new emerging plant into a new pot of potting soil. Continue to keep a humid environment for about 2 more weeks until active growth begins.[6]
Practical differences with using different cutting types
Stem cuttings
In temperate countries, stem cuttings may be taken of soft (green or semi-ripe) wood and hard wood which has specific differences in practice. Stem cuttings of soft wood is taken in spring, while from hard wood, they are taken in winter. Also, of soft wood the upper branches are taken (with a length of 5-15cm) and with hard wood, the lower branches are taken instead (with a length of 20-25cm). Finally, soft wood cuttings are planted above ground and hard wood cuttings are totally submerged with soil. With hard wood cuttings, several cuttings are also bound together (to a bushel).
See also
References
- ^ Winterborne J, 2005. Hydroponics - Indoor Horticulture [1]
- ^ Scion cuttings description
- ^ Eye cuttings decription
- ^ Certain plant species having more succes with certain types of cuttings
- ^ How to make your own rooting hormone
- ^ How to make your own rooting hormone by Marilyn Pokorney
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