Whether you’re running a large-scale commercial grow operation or just cultivating a few plants in your closet, there’s going to come a time when you’ll want to clone some of your favorite or more commercially popular strains of cannabis.
So, why clone instead of growing from seed?
Cloning ensures the grow-to-grow carryover of what you love about a particular strain of cannabis. While plants that start from seed may grow a bit more vigorously, plants you start as clones (assuming you’re cloning a female plant) will resemble the parent plant with no surprises, such as getting a male plant that will go to seed.
Large-scale licensed producers generally (but not always) use aeroponic, or “air” cloners that have built-in ways to control the variables — i.e., temperature and humidity — that will determine success. Smaller-scale or hobby growers may use less expensive propagation domes that require more attention and manual hardening of the clones. In this article, we’ll explore the advantages and disadvantages of these cloners.
As with many elements of gardening and horticulture, it isn’t so much what we don’t know that will kill our plants, but what we don’t do — like keeping equipment and work benches sterile. On the other hand, we growers sometimes behave like overprotective mothers, fussing a little too much over our plants. In other words, we may need to back off a little, especially when it comes to cloning. Or, as one veteran grower put it, “Put your clones in a protective dome, tape it shut and go on vacation for a week!”
Whether you’re a newbie at cloning or a grizzled old pro, these tips will help ensure you have success in the process of cloning.
1. Get Organized! Remember To Tag Your Plants
In a large grow operation — and even in a small one — it’s easy to become distracted and fail to tag the clones you’ve taken from a mother plant. If this sounds implausible, it shouldn’t — it’s happened to many growers.
“Just remember to be organized,” advises Kevin Cleary, a veteran West Coast grower now working with Verde Natural, a Denver-based grower/dispensary. “If you’re taking cuttings from a whole bunch of different strains, make sure you always check the tag on the plant. This has happened to me; it happens to just about everybody.
“You take it from one strain, you grow it out, and then it’s not until the end of the growing cycle that you say, ‘Oh shit, this isn’t what it’s supposed to be.’ At that point, you may have cloned a whole batch. I’ve seen grows where it took up to a year to get back to the right plant because there were so many that were mixed up and mislabeled.”
2. Give The Mother Plant A Few Weeks To Grow
“I personally get the best results with cloning after the mother plant is at least six weeks old,” says Christopher Sloper, veteran grower, consultant to the industry, and author of the book The LED Grow Book: The Way to Grow. “Some slower-growing strains might take more than two months to produce top-quality clones.”
3. Select Healthy Plants
“The most important aspect is to make sure you’re taking cuttings from a healthy plant, no matter what the size is,” Cleary advises. “If the clone comes from a plant that has pests or diseases, you’re starting out with a weak beginning, which will turn into poor growth.” He says to be particularly aware of plants that are infected with spider mites. The bottom line is to inspect your mother plants carefully before taking a cutting.
4. Sterilize Your Grow-Op Equipment
This falls under the category of knowing what to do but not doing it. It’s akin to knowing that you should eat a healthy salad, yet choosing greasy fries instead.
“Keep cleanliness in mind,” Cleary advises. “It’s very easy to overlook. A lot of growers take a lazy approach to cloning — they don’t wash their equipment, they don’t use properly sterilized scissors, or they dip their tools in an old cup with old water.”
He suggests when taking cuttings to start with a clean cup and dip scissors in isopropyl alcohol after taking each cutting.
5. Take Cuttings From The Terminal End Of The Plant
“The best place to take cuttings is from the younger shoots at the very end,” Cleary says. “I like at least three or four nodes, and cut at a 45-degree angle with clean scissors or X-Acto Knife.” He makes the last cut right at the lowest node on the cutting.
The older the plant, the more you can top it off. “Every time you top the plant, it branches into two more shoots,” Cleary explains.
He advises taking several cuttings over time from a large mother plant or, if you don’t have the room to store the mother plants, take a few cuts from smaller plants before they head into the flowering room.
6. Treat Your Cannabis Cuttings With A Rooting Hormone
It may not be absolutely necessary, but you’ll most likely have more success with rooting if you treat the cuttings with a rooting hormone. Cleary uses a 200x aloe product for the salicylic acid it contains, which stimulates the formation of roots. He says if you have an aloe plant around your home, you can pinch off a stem and soak the cutting in its clear aloe gel overnight before sticking it in medium or a grow cube. You can also use any product containing the rooting hormone indolebutyric acid (IBA).
7. Concentrate On The Root Zone
It’s all about the root zone. Establish strong roots before transplanting into a large pot or grow space.
“I’ll remove all of the leaves except the top ones, and cut off the tips of [the top remaining leaves],” Cleary says. “You’re trying to promote root growth, not necessarily photosynthesis. I’ve seen people keep the leaves on and have successful rates, but I typically remove all the leaves except the top ones.”
Medicinal marijuana clone cuttings rooted in soil on the floor of a Mylar grow tent as part of an indoor grow op.
8. Choose The Right Grow Medium
Cultivators are using a wide variety of grow cubes and medium to root clones successfully, so it may just come down to personal preference.
“Honestly, I don’t think it matters that much,” Sloper says when asked about the best grow medium for rooting clones. “I’ve seen success in every media — from rockwool to bark-based cubes to aeroponic cloners. They all work. The best success comes from having the healthiest cuttings possible. Experiment and figure out what works best for you.”
9. Maintain Proper Hydration Levels For Successful Cloning
This tip perhaps falls into the overprotective mother category. Sometimes, we can kill our plants with kindness, and providing too much H2O is one way to do it.
“Keep the starts moist but not wet,” advises Ted Gurin, grower and co-founder of Trichome Farms, an award-winning craft cannabis farm located in the rolling red hills of Dundee, Oregon. “Most people kill their clones by putting too much moisture on the plug and keeping it wet. Roots will look for water when they need water; they will not grow when the plug is saturated.”
10. Keep A Watchful Eye On Your Clones, And Clean Often
Seems like common sense, but as they say, the only thing about common sense is it’s not that common. Gurin says there is a risk of green slime building up on the stem of the plant while it’s in the clone box, which could be a sign of bacteria, root rot, or even bad pH.
“Cleaning regularly and keeping the temperature steady will avoid that,” he says.
11. Properly Harden Off Clones
When cloning with a dome rather than an air cloner, you’ll have to harden off your cuttings before transplanting them into a pot or garden bed.
“Keep the vents closed for a few days [after placing them in a cloner], and then if [your cuttings] are looking healthy, open the vent a quarter turn every couple days within the 14 days it takes to root,” Cleary advises. “At the beginning, keep the vents closed, open them a quarter of the way after four or five days, then the next couple of days to halfway open, then take the dome off for half-hour increments.”
According to Cleary, there’s a simple test to know if the cuttings are properly hardened off. If you put them under lights and they droop, they’re not properly hardened off. If this is the case, place them in a plastic baggy to create a greenhouse effect. Spray a little water inside the baggy and watch for it to bounce back, which it should fairly quickly. When it does, take the baggy off at regular intervals for a couple of days until the cuttings look healthy and strong.
12. Get Ready To Transplant Your Clones
If you haven’t doted over your cuttings too much — or neglected them due to poor sanitation practices — you should now be ready to transplant them into their new home. Again, growers have different ways to prepare for this event. Cleary likes to inoculate the soil or grow medium with mycorrhizae or other organic compounds.
Always keep best practices in mind: Handle the transplants with care soon after removing them from the cloner; don’t shock them by dumping clones in warm water or loose medium. Firm the medium around the plant and water in gradually. Now watch them grow!
13. The Pros Of Aeroponic Cloners
Aeroponic cloners appear to be the choice for many of the large-scale commercial operations. Growers can clone up to 128 plants at a time, and they don’t need to fuss a lot with the clones because of the environmental controls inside the cloners.
“These air cloners are kind of expensive, but if you’re looking for consistency on a product scale, you can get boxes [of] up to 128 [plants] and they’re just plug-and-play. You check the pH and temperature, and the results are just amazing,” Cleary says.
He says for best results when using an aeroponic cloner, the pH should be between 5.6 and 6.0, with the temperature around 75 degrees Fahrenheit.
Another advantage is ease of use.
“It’s harder to train someone on the cubes versus the EZ-Clone,” Cleary continues.
Aeroponic cloners also come in smaller, more affordable sizes that accommodate about nine clones at a time for the hobby grower, which Cleary says could be a good investment for the smaller-scale grower.
“It definitely can be easier if the water is kept at the right temperature and pH level,” Cleary says.
14. The Cons Of Aeroponic Cloners
Aeroponic cloners work great to do clones on a large scale, but there is one potential drawback.
“Personally, I don’t like cloners in either home or commercial settings. They’re outstanding when they work, but they have one major fault: They need power,” Cleary says.
He says if the power to the cloner goes out, you have only a few hours before you’ll see the cuttings start to droop. He advises using a cycle timer and the largest uninterruptible power supply (UPS) you can afford.
“Since it’s impractical to power just about any cloner on full for a long length of time on a UPS, I suggest you run them for about five seconds on and 30 to 45 seconds off,” Sloper suggests. “This will maintain high humidity levels and only consume a fraction of the total needed power. Suddenly, the cost of a cloner, cycle timer and UPS becomes prohibitive to the home/hobby grower.”
15. Set Yourself Up For Cannabis-Cloning Success
“If you start out with good, healthy practices, you’re setting yourself up for success,” Cleary states. “Using scissors that have been soaked in isopropyl alcohol or hydrogen peroxide for sterilization, or a brand-new razor blade or X-Acto Knife dipped into alcohol between plants, will drastically reduce your risk of catching pathogens and transferring them from plant to plant.”
16. Find Out What Works For You And Your Grow Op
After talking with different growers, it’s apparent you could argue all day on how to actually take a cutting. Cut at a 45-degree angle? Scrape the stem? Take it during a full moon?
“I’ve taken thousands of clones using all the popular methods — cutting at a 45-degree angle, scraping the stem to expose inner cells, placing the cutting tip into water prior to making a final cut, and using rooting hormones — and I’ve determined that it really doesn’t matter, at least for me,” Sloper says. “Now, I simply take a cutting and place it into a cube that has just been wetted and not pH adjusted. My clones come out very healthy with just about a 100-percent success rate. I believe that some of those techniques might help, but mostly you’re just overhandling the sensitive cutting, causing harm or just wasting time.”
