How to Clone Cannabis

Many home gardeners look forward to the winter.

That’s when they set up grow lights in their basement to start the tomatoes, peppers, and squash they’ll be transplanting into their garden come springtime.

There’s a sense of accomplishment and pride associated with successfully growing seedlings indoors, which to some dedicated gardeners is almost as satisfying as the crop they harvest during the warm weather.

Not as many marijuana growers feel the same way.

An enormous number, whether they’re growing indoors or outdoors, choose to start their crop with clones instead of spending their time and effort germinating seeds.

To those who aren’t familiar with the term, “cloning” may conjure images of super-secret government labs, or scientists working to create a baby from human cells.

In the cannabis world, though, clones are nothing more than cuttings taken from existing plants and grown into new plants.

Let’s dig a little deeper.

What Are Marijuana Clones?

Lots of flowering plants are grown from clones — they’re just not called “clones.”

If you take a branch or stem from a begonia, let it grow roots in water, and then transplant it to give to your mom on Mother’s Day, that’s a clone. The horticultural world, though, calls it a cutting.

A cannabis clone is created by taking a small part of a weed plant, placing it into the soil, and letting it grow into a new plant that’s identical to the “mother” plant.

Why is it called a clone and not a cutting?

People who take cuttings of other plants or vegetables aren’t usually concerned about genetics. They just want some pretty flowers or tasty vegetables.

Cultivators and growers, however, carefully select a mother plant to ensure that its clone will have the same genetics. That way they have an exact copy of the strain they want to grow, and they know the characteristics and THC level they should expect from the new plant. They can also be sure that they have female plants.

Is cloning the right way to go? It depends.

Cloning Marijuana Plants vs. Growing From Seed

Growing marijuana plants from seed can be rewarding, but there are major downsides.

• Seeds may produce male plants, potentially making half of your crop unusable.
• If your tomato or pepper seeds don’t germinate, you can always buy seedlings from a garden center or fresh produce from a store or roadside stand. Weed’s a different story.
• Seeds are generally more expensive since cloning from a plant you already own is free.
• Starting with seeds can add a month to the growing cycle.

That last disadvantage is why many people choose to use clones instead of seeds; they’ll be able to harvest their buds much sooner. The other big benefit, as we’ve mentioned, is that a clone is a plant that you know you’ll be happy with.

Here’s how to create one.

Cloning Marijuana: Step-By-Step

Choosing a Mother Plant

The first step, needless to say, is to select a mother whose flavor, aroma, and psychoactive effects (or medicinal benefits) you want to replicate.

Look for a mother plant that is fully healthy and growing rapidly. You’ll want genetics that ensures that the clone will have lots of trichomes, will be mold- and pest-resistant, and will produce a bountiful harvest. Never clone autoflowers because their growing cycle is too short.

Mature plants can be cloned, but you’ll have to carefully baby the new plant over its first few weeks. You’re better off cloning a younger plant that’s in the vegetative stage, ideally around 2-3 months old. If it’s fewer than two months old, its roots may not take.

Cuttings taken from an indoor plant will do better indoors, and those from outdoor plants prefer to grow outdoors. That’s simply because they’re already accustomed to the environment.

Finally, experience shows that sativa clones take better than indica ones, and clones taken from plants grown from feminized seeds may become hermaphrodites.

Preparing the Mother Plant

One common mistake growers make is to simply take a cutting from the mother plant without realizing that it’s not ready to take root.

A plant in the vegetative stage has lots of nitrogen in its leaves and stems. When a cutting is put into the ground, the new plant will take that as a sign that it should grow leaves instead develop roots.

The way to avoid the problem is simple: stop fertilizing the mother plant 3-4 days before you’re going to clone it. That will clear most of the nitrogen from your cutting. Don’t worry, it won’t do any long-term damage to the mother.

Taking the Cutting

Before starting, disinfect your cutting tools (make sure they’re sharp) and put on gloves. Plants will be susceptible to infection during the process, so the process has to be sterile.

1. Find a sturdy branch toward the bottom of the mother plant that’s about 5-6 inches long.
2. Cut the branch above the node, at a 45° angle (the way you’d cut roses to put into water).
3. Remove leaves and excess nodes from the bottom of your clone, leaving two nodes and at least one or two sets of leaves at the top. This will promote growth.
4. Scrape away some tissue from the bottom inch of the stem so the cutting will root more quickly. This is called “wounding.”

You’re now ready to prepare the clone for planting.

Prepping and Planting the Clone

It’s best to have everything ready for this stage before taking your clone. You can purchase what you need at any garden center.

1. Dip the end of the clone into a rooting solution or gel.
2. Plant the cutting into your chosen growing medium. It can be a stonewool cube, peat plug, coco coir, or sterile potting soil. All should be saturated with cloning nutrient solutions before planting.
3. Trim an inch or two off of the clone’s fan leaves, to prevent moisture loss.

Caring for Marijuana Plant Clones

Young clones initially want low-intensity light, a temperature between 60°-70° and 80%-100% humidity.

CFL lights (12-16 hours per day) and regular misting with water or a diluted nutrient solution several times per day will ordinarily do the trick. Many growers either use an auto-cloner machine, which is an enclosed dome that controls humidity and automatically sprays the plants, or improvise with a plastic dome or freezer bag.

After 4-5 days, the clones should be stable enough that they don’t have to be babied as much. The dome can come off, humidity can be lowered to 75%-80%, and stronger nutrients can be used.

In about ten days or so, your clones should be ready to transplant. To be sure, check the roots; the white roots should be a couple of inches long.

That may have been a little more work than germinating your plants from seed — but you’ve shortened your growing time by a month or so. Enjoy your cloned harvest.

Cloning Marijuana Guide: FAQ

Q: Can you take more than one clone from a mother plant?
A: Absolutely. In fact, as long as you take multiple cuttings from the bottom of the plant, that can benefit the mother, too. Those branches have trouble growing once the plant has reached the flowering stage and they don’t get much light, and they use up some of the nutrients that could be better used to produce buds.

Q: Are strains likely to become less potent or less hardy over generations of cloning?
A: That subject is fiercely debated by cultivators. Some claim there’s no scientific reason that strains would degrade because of cloning, while others insist they’ve seen it first-hand. Clonal degradation could, of course, be blamed on genetic mutations. But the best guess is that even though the strain’s genetics don’t change during cloning, the plants may become less hardy or vigorous because each generation is exposed to different environments and stressors. The important thing for home growers to remember is that if they take a cutting from a strong, healthy mother — and treat it properly — they should wind up with a strong, healthy clone.

References

1. Schwabe, A. L., & McGlaughlin, M. E. (2019). Genetic tools weed out misconceptions of strain reliability in Cannabis sativa: implications for a budding industry. Journal of cannabis research, 1(1), 1-16. [1]
2. Campbell, L. G., Naraine, S. G., & Dusfresne, J. (2019). Phenotypic plasticity influences the success of clonal propagation in industrial pharmaceutical Cannabis sativa. PloS one, 14(3), e0213434. [2]
3. De Witte, L. C., & Stöcklin, J. (2010). Longevity of clonal plants: why it matters and how to measure it. Annals of Botany, 106(6), 859-870. [3]