How to Clone Cannabis
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Cannabis cloning offers a helpful way to preserve valuable genetics and ensure a consistent supply of your top strains. As a cannabis producer, you may be interested in cloning your plants to create identical copies, which are almost guaranteed to have the same high-quality traits as the original.
To clone a cannabis plant, you will need to take a cutting from a healthy mother plant and then root it in water or soil. Once the cutting has taken root and begun to grow, it can be transplanted into its own pot and treated like any other cannabis plant.
This article explains the advantages and drawbacks of cloning cannabis and reveals how to get started with your cannabis plant clones.
Benefits and obstacles of cloning cannabis plants
Cloning is often the preferred method of propagation for commercial growers as it offers a number of advantages over growing from seed. First, it is faster to clone a plant than it is to grow one from seed. Plus, clones are genetically identical to the plant they were taken from, so you can be sure that your plants will have the same qualities as the parent plant. Another benefit of clones is that you know all cuttings from a mother plant will be female, which is important for ensuring high yields. On that note, feminized seeds can be expensive to purchase and cloning enables you to avoid that cost.
However, it is worth noting that clones can be more difficult to care for than seedlings, so it is important to choose a healthy parent plant and ensure you have a solid cloning setup before you begin. One of the biggest concerns is that clones are more susceptible to environmental stressors than plants grown from seeds, so clones require more precise conditions in order to thrive. Another potential downside is that clones may not develop as robust a root system as plants grown from seeds, which can ultimately impact yield.
In general, cloning does not necessarily guarantee identical plants. Even with identical genetic makeup, each clone may exhibit slightly different characteristics due to variations in growing conditions. And in some cases, clones may inherit genetic mutations that can affect the final product.
How to clone cannabis plants
While cloning sounds like a complex process, the steps are relatively simple. The main thing is to make sure you care for your clones properly to ensure they flourish into well-nourished, disease-free plants.
David Kessler, chief science officer at Agrify, provides an overview of the process.
“In terms of the basics of cloning, what we’re talking about is typically called vegetative propagation,” says Kessler. He explains that a grower is essentially severing a piece of a plant, and while the original plant continues to grow, the severed piece is forced to make roots. A cutting that has roots and shoots is then a fully viable plant.
Here are the basic steps for cloning cannabis:
Step 1: Identify the ideal mother plant
Since you will be creating a genetically identical plant, you first need to select the ideal plant from which to take a cutting. When choosing the mother plant, there are several factors to consider, depending on your reason for cloning. For example, strain is important to most growers, as is yield. But the most crucial factor to consider is the mother plant’s health.
“The viability of a clone is determined by the health of the mother plant that it’s cut from,” says Kevin Rampelberg, vice president of cultivation at Ascend Wellness Holdings. “The health of the mother room or nursery is one of the most integral parts of growing cannabis.”
Step 2: Take a cutting from the mother plant
Next, you’ll need to identify where to cut the mother plant. “You always want to cut right above a node to allow for future growth,” says Rampelberg. Once you’ve removed your cutting, you cut the base of the stem at a 45-degree and strip the leaves from the lower two-thirds of the branch. “I will trim back all leaves below the terminal shoot and then cut 30% of the main leaf edges off at the terminal shoot,” says Rampelberg.
Step 3: Prepare the clone for rooting
To give the plant the best chances of growing healthy roots, Rampelberg recommends using a rooting hormone (for example, cloneX gel) or aloe powder to coat the base of the stem (where the cut was made). This can then be placed into the rooting medium, which should be pre-soaked in a water-nutrient solution. Common rooting mediums include rockwool, peat moss, or soil.
Step 4: Place the cutting in a humidity dome
Once planted, the cuttings must be kept in ideal conditions to encourage the growth of new roots. Rampelberg advises placing the clones in a tray covered with a clear dome. “Then place the clones under a T5 light or equivalent for root growth.” He adds that intense light is not needed, but the light can remain on for 18–24 hours. “RH (relative humidity) should be 75-85% and the temp between 75-85 degrees,” advises Rampelberg.
Step 5: Monitor and care for your clones
It’s now time to nurture your clones as they start to produce roots. “Throughout the next few days, the dome will be removed to get fresh air to the clones as well to check on the saturation of the medium,” says Rampelberg. “After the initial few days, you can either open vents on the domes or tilt the domes to recirculate fresh air. The domes will eventually be completely removed when roots start to show. Under ideal conditions, you should start to see roots anywhere from 6–10 days. When roots have been established, then it’s time for transplant.”
As Kessler notes, while the plants are recovering from the initial separation from the donor, they’re in homeostasis, just trying to survive during this stressful period, and there will be very little growth. However, once a clone has a root system (which then gives it the ability to bring in moisture and nutrients), the cutting will really take off and become its own plant. “Once they have roots, you’re going to look for positive top growth,” he advises. This is where new vegetative material starts to grow.
Best practices for cloning based on recent research
While cloning cannabis plants isn’t new, with the desire to increase yields of healthy, desirable crops, studies have focused on best practices for cannabis cloning. Kessler points us to one such study by Kaplan et al. This examined the effects of several variable factors, including leaf number, cutting position, rooting hormone, and leaf tip removal.
Kessler summarized some of the key findings: cuttings with three leaves or more had better root quality; using a cloning gel delivered 2.1 times higher root success and 1.6 times the root quality compared to not using a cloning hormone; and removing the leaf tips actually reduced the success rate from 71% to 53%. It also found that, contrary to popular belief, the cutting position doesn’t matter, and clones from apical and basal locations will have the same success rate.
The leaf tip cutting component of the study is particularly important – Kessler explains that it’s common among producers to snip the tips of leaves to lower the surface area (limiting water loss) and ensure each plant gets equal light. However, based on the study results, cutting the leaf tips can be stressful to the plant; growers should avoid this practice and instead space out plants, so they have enough light and airflow.