A cannabis plant that is a genetic copy of the mother plant. When obtained from a reputable breeder, a clone is a young female cannabis plant with stable genetics. Growers typically select to raise clones instead of seeds when they would rather not risk getting a plant that's male or with poor characteristics (e.g. low yield, undesirable smell, etc.).
“I get clones from a shop, to make sure I don't grow any males in my garden.”
“This mom is healthy enough to cut into clones.”
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More about Clones
A cannabis clone is a prime example of asexual propagation — replicating a single parent plant outside the means of sexual reproduction. Cannabis clones typically start by taking a cutting of a stable mother plant, then providing the necessary conditions for the cutting to grow into a genetically identical plant.
A clone's central purpose is to reproduce and preserve the genetic identity of a cannabis plant. When grown under the same environmental conditions as the mother plant, a clone is infinitely more likely than a sexually propagated plant to exhibit the mother's physical and chemical traits. As long as environmental conditions remain consistent throughout its life cycle, a clone should have nearly identical cannabinoid and terpene profiles to its mother plant. It should also mirror the mother's ability to take in nutrients and resist pests or fungi.
Why Clones Over Seeds?
There are several reasons why both cultivators and home growers prefer clones over seeds. Cannabis is a heterozygous plant, which means it naturally reproduces a diverse set of offspring. Cultivators and home growers depend on continuity of plant characteristics, which sexually propagated cannabis cannot provide.
For home growers, clones save time and money. It can take up to a month to determine the sex of a seed. With clones, home growers know and control the plant's sex from the beginning; saving weeks of energy, nutrients, and expenses that might otherwise have been wasted on an unwanted male plant. Clones also tend to sell for roughly the same price as seeds.
Cultivators also prefer clones for their genetic consistency. Identical plants allow for controlled experiments, which cultivators rely on to evaluate and replicate effects, as well as determine optimal feeding schedules, flowering times, and nutrient recipes. With all of these advantages in place, cultivators are much more likely to reproduce favorably.
But clones also have their disadvantages. Lack of genetic diversity is a good thing for growers, but it can also have catastrophic consequences. If exposed to adverse environmental effects for which they have no defense, a group of genetically identical plants can be wiped out. Fortunately, in the overwhelming majority of cases, the pros of genetic consistency in clones far outweigh the cons.
How to Take Clones from a Mother Plant
Taking clone cuttings from a mother plant is a relatively simple process, which typically requires the following equipment:
- A strong, healthy mother plant with vegetative limbs 4-20 inches, or 10.16-50.8 cm, in length
- Razor Blade
- Cup with water
- Rooting medium
- Rooting hormones (optional)
- Fluorescent light
- Cloning dome or plastic bag to cover the cutting
When selecting a mother plant for cutting, make sure she's at least a month old and has shown clear signs of being a female. Taking cuttings from a mother plant can stunt her growth, so it's important to make sure she is healthy. If a plant looks either under- or over-watered, refrain from taking cuttings. A mother plant should be kept in a prolonged vegetative state; ideally, in a separate space from other plants, under an 18 on/6 off light cycle.
Before you begin cutting, it's crucial to sterilize your blade to avoid quick-spreading, deadly bacteria from infecting your clones while they develop their roots. When selecting clones from the mother plant, look for branches with four or more nodes, or points in a branch where new leaves appear. Professional recommendations on proper branch length for cutting range from 4 to 16 inches, or 10.16 to 40.64 cm.
Make sure to cut the branch at a 45-degree angle, then take away all growth below the top two nodes. Put the cutting in water immediately after grooming to avoid embolisms, or air bubbles that block the transpiration stream and cause wilting. Rooting gels and other solutions are optional, but they further reduce the risk of embolisms, as well as provide hormones and nutrients that may speed up the rate of growth.
Once you've successfully made all of your cuttings, dip them in your rooting gel and gently place them into a medium. If you're using a rockwool cube, do not put the clone into the hole. Instead, use the cutting to pierce the cube. Doing so will ensure that no light hits the roots, and that the cutting gets maximum coverage.
Prior to producing roots, clones require a high level of humidity. Place the cutting into a cloning dome and keep the humidity between 75-90% until their roots are capable of intaking water.
Roots should begin to form within 7-14 days, and signal that the clones are ready to be planted.
How to Store Clones Long Term
If you want to save clones for later use, or have backups on hand in case a problem occurs with some of your cuttings, storing them in the fridge is typically a safe, simple way to do so. Clones are safe to store in a sufficiently cold refrigerator for 2-3 months.
For best results, put the clone in a wet paper towel, place in a resealable bag, and close the bag with some air left inside. Place the bag carefully in your fridge and replace the air inside the bag at least once a week. Do not put bags in the freezer. Placing cuttings in temperatures below 40°F means running the risk of bursting plant cell walls.
When you remove cuttings from the fridge, put the stems in water for about 30 minutes to warm them up. If your cuttings have been refrigerated for an extended period, they may take longer to root. To speed up the process, cut a half-inch, or 1.27 cm, off the stem, and dip the raw end in rooting gel when possible.
How and Where to Purchase Clones
Dispensaries are typically the best place to purchase clones. Over time, dispensaries will become more sophisticated at identifying cultivars and ensuring plant legitimacy. Buying a clone from a dispensary usually means you're going to get the plant you paid for, especially if you go to a source you already know and trust.
The only major downside to purchasing clones is the risk of incurring pests or molds. Most dispensaries carefully examine the clones they bring in for powdery mildew, as well as insects such as spider mites and root aphids, but it's difficult to catch all of them. If you purchase clones from a dispensary, practice due diligence and double-check for pests before you bring the plants home. Be on the lookout for spider mites, as they're increasingly resistant to organic pesticides.
Also pay close attention to a dispensary clone's roots, size, and color. Clones should have visible roots on the surface of the medium. They should be no less than 4 inches, or 10.16 cm, in height, and preferably 6 to 8 inches, or 15.24 to 20.32 cm, with thick stems. They should also be bright or dark green with minimal yellow spots.
Finally, if you bring clones home from a dispensary, quarantine them for a week or two to avoid contaminating the rest of your garden with any pests or molds that may have snuck through. Don't hesitate to use organic pesticides to minimize further the risk of introducing a pest or fungus the clone may have picked up from a dispensary, or during transportation.