Propagating plants from cuttings is a cost-effective way to produce a new generation of plants. The growth response from plants can be exploited by gardeners and growers to produce a whole new generation of plants for a fraction of the cost of buying mature specimens. However, certain conditions must be met to ensure cutting survival and to induce the necessary root and vegetative growth required for those cuttings to mature and survive the outdoor environment. In this article, we will look at the propagation environment and focus on what plants require to survive, why cuttings sometimes fail, and how you can master the techniques of cutting propagation to maximize production in your nursery.
Microclimate: Light, Humidity, and Temperature
There are three environmental factors that growers can manipulate to elicit the desired response in their cuttings. These are the microclimate, the soil or medium, and pests and diseases. The microclimate refers to the amount of light, humidity, and temperature of the propagation unit. Light is important for plants to photosynthesize. The carbohydrates produced through photosynthesis allow the plant to develop roots and leads, both of which are essential to ensure cutting success.
The amount and quality of light are important. Longer days provide the plants with more energy to photosynthesize, allowing roots to develop more quicker. The quality or color of the light can also influence root development. Red shade nets change the light quality towards the blue and green wavelengths, which has been shown to increase root development. However, higher light levels can also increase the ambient temperature, which can put severe stress on the cuttings. Growers must therefore compromise to find the highest light level without putting temperature stress on the cuttings.
Water: Liquid and Humidity
Water, both in its liquid form and as humidity, is possibly the most important factor in cutting production. Keeping cuttings turgid is a prerequisite for root development. A balance must be maintained between the water taken up by the cuttings and that loss through transpiration. Increasing humidity in the propagation unit and lowering the surface area of the leaves will help minimize water loss.
Capillary mats are one of the most common methods of applying water, not only to keep the cuttings turgid but to cool them as well. Capillary mats are used to draw water from watertight basins into the rooting media. This method not only saves water but also keeps more or less constant moisture levels in the rooting medium. Water retention will be influenced by the rooting medium selected, which we will focus on later.
Temperature influences not only the rate of root development but also overall plant stress. Warmer temperatures will encourage rapid root growth, with many plants benefiting from warm feet and cool heads. The propagation unit itself will help to retain heat, but in very cold environments, bottom heating could be considered.
Root development is dependent on the availability of gases both around the leaves of the cuttings and in the rooting medium. Carbon dioxide is necessary for photosynthesis, and oversaturation of the rooting medium will exclude the necessary gases required for root development. In some areas, carbon dioxide and other gases can be pumped into the propagation unit, but open vents can often achieve the same result with little extra cost.
Soil or Medium
The following are prerequisites for rooting media:
- The media must retain sufficient water.
- The media must be aerated to allow roots to grow.
- The media must be cost-effective against the price of the eventual mature plants.
For more information on the different rooting media, you can use in your propagation units, check out the ebook in the description. Some media can also contain small amounts of nutrients that can supplement the young cuttings.
Fertigation and slow-release fertilizers are also common methods of providing nutrients to the cuttings during the rooting process.
Pests and diseases can greatly affect the success of cutting propagation. It is important to maintain a clean and sterile environment to minimize the risk of infection. This can be achieved through the use of sterilized tools and equipment, as well as the regular cleaning and disinfection of the propagation unit. In addition, growers should also be familiar with common pests and diseases and take appropriate measures to control them.
Why cuttings sometimes fail
Despite the best efforts of growers, cuttings may sometimes fail to root or die before they can be transplanted. Some of the reasons for this can include:
- Poor quality or damaged cuttings: Cuttings that are taken from weak or damaged plants may not have the necessary energy reserves to generate new roots and leaves. Similarly, cuttings that are not taken properly or are damaged during handling may also fail to root.
- Inadequate environmental conditions: As mentioned earlier, the environmental conditions within the propagation unit can greatly affect cutting success. If the unit is too hot, too dry, or too humid, the cuttings may not be able to survive.
- Infection by pests or diseases: As also mentioned earlier, pests and diseases can greatly affect cutting success. Even with the best efforts to maintain a clean and sterile environment, pests and diseases may still find their way into the propagation unit and infect the cuttings.
- Improper rooting medium: The rooting medium used for the cuttings must be able to retain sufficient water and allow for proper aeration. If the medium is too dense or too loose, the cuttings may not be able to develop roots properly.
- Lack of nutrients: Cuttings require sufficient nutrients to generate new roots and leaves. If the rooting medium or the water used to irrigate the cuttings does not contain sufficient nutrients, the cuttings may not be able to survive.
Mastering the techniques of cutting propagation
To maximize production in a nursery, growers must be able to master the techniques of cutting propagation. Some tips for success include:
- Take cuttings from healthy plants: Cuttings taken from healthy plants that are in good condition will have the necessary energy reserves to generate new roots and leaves.
- Use a suitable rooting medium: The rooting medium used for the cuttings must be able to retain sufficient water and allow for proper aeration. Some common rooting media include peat moss, vermiculite, perlite, and sand.
- Maintain suitable environmental conditions: The propagation unit must be kept at a suitable temperature, humidity, and light level to ensure cutting success. Growers must also be aware of the potential for pests and diseases to infect the cuttings.
- Use appropriate tools and equipment: The tools and equipment used to take and handle the cuttings must be clean and sterile to minimize the risk of infection.
- Monitor progress: Regular monitoring of the cuttings will allow growers to identify any potential issues and take appropriate action to address them.
Propagating plants from cuttings can be a cost-effective and efficient way for growers to produce new plants for their nursery. By manipulating the microclimate, soil or rooting medium, and pest and disease management within the propagation unit, growers can elicit the desired response in their cuttings and maximize production. With the right techniques and environmental conditions, cutting propagation can be a highly successful method of plant propagation.