Transcription
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I'm Harley Smith, and this is the Master Growers course. Today, we're going to continue our series on plant propagation with tips for successful cloning. Remember, healthy moms equal healthy clones.
The first thing you need to do to have successful cuttings is choose the best of the best of your mother plants. If it has a disease, don't use it. If it's spindly or weak, don't use that for cutting. You want mother plants with thicker stems, thicker cell walls, lots of stored energy, nice dark turgid leaves, and excellent rooting.
Remember too that clones are genetically identical to the mother plant. If you give it the same environment, the same nutrients, and the same love, you can get the same results every time. So again, always choose your best plant for your mother. Choose the best plant for your mother with the superior characteristics that are your priorities.
Once you choose your healthy mom, here are a few tips for better cloning and better results. First of all, you want to take a cutting from just below a node. A node is where the leaf attaches to the stem of the plant. It's best to take a cutting just below the node with a very sharp scalpel or very sharp clean scissors. If you use dull scissors, you pinch the stem when you're taking the cutting. When it unpinches, it pulls oxygen and air into the vascular system, which could create an embolism—a little bubble of air in the vascular system—which prevents the plant from taking up water, and the cutting could wilt.
So the first thing to do is think of it as a surgical cut with very sharp scissors, a razor blade, or scalpel. Choose a branch tip with at least three or four nodes, cut below the bottom node, and then remove that node from the plant. Cut very evenly with the edge of the bark of the plant because where that node was, the node produces a bud. It could develop into a branch, it could develop into a flower bud, or it could differentiate and grow into roots.
Most of the roots are going to come from that nodal area with new developing root cells. Also, cut off some of the excess leaves. If you have too bushy of a cutting, most of the energy of the plant that's stored is going to go to support and maintain the leaves. Well, you want the energy to be directed to grow new roots, so cut off all but about two or three leaves from that cutting.
Next, stick the end of the cutting into a rooting gel. Rooting gels are cellulose-based products that help to seal the edge of the cutting, the edge of the stem. They seal the wound, help initiate rooting, and also help prevent the plant from taking up oxygen. The rooting hormone in the gel is called indole-3-butyric acid (IBA). That's an auxin; it's a hormone that signals the plant to make roots.
Once it initiates the rooting process, though, the job is done. One of the tips that I would recommend is don't double dip. If you take a cutting, stick it in the gel, and you don't see anything happening for a while, don't panic. Because even if you got some microscopic root hairs, if you dipped it again, it would actually inhibit rooting instead of accelerating it. So dip it once, stick it, and then stand back and let nature take its course.
Also, remember to store your gels in the refrigerator after you open them. If it gets contaminated with bacteria, some bacteria make an enzyme called cellulase. It breaks down the cellulose into simple sugars. So if it gets contaminated, then you give it a shake, it'll be watery. Throw it away, get some fresh. Don't dip your cutting directly into the bottle. If you do that, again, you're going to contaminate the whole bottle of cloning gel.
It's better to pour a little bit into a shot glass or into some other container and then just use what you need for that day. Dispose of the excess; don't pour it back into the bottle. You want to keep it fresh from time to time, from use to use.
Once you take your cutting and prepare it, dip it in the cloning gel. You can either put it directly into your growing medium, your soilless mix, or your soil. Or better yet, try putting it into a clone machine. A clone machine is an aeroponic system where the bare stems are suspended in air. It creates a mist chamber in the root zone. The stem is held in a neoprene insert, and the stem is held below in the mist chamber.
So the misting heads are spraying water and nutrients directly onto the bare stem. That means there's more oxygen, you get faster rooting, and healthier roots. Now, one tip that I like to use is when I'm taking my cuttings and dipping them into the gel, I turn off the clone machine and set it up so that every plant is already planted. That gives the plant a chance to absorb a little bit of the gel to harden up a little bit on the edges and the tips of the stem.
Once that happens, I know that the auxins are going to be able to have their effect. Then I turn back on my clone machine so it doesn't just wash off the cloning gel before it has a chance to do its job. But don't forget to turn it back on. That's a common mistake; I've done it myself. I see my wife off camera; she's shaking her head, nodding her head yes. A lot of times we turn it off, we put everything in, and our job is done.
Don't forget to turn it back on because if you do, if you forget, you come back with no water. Those poor little clones will be drooping and dying, so make sure it's on. But then let nature take its course for a while. Once you stick the cutting, wait till it has a chance to root. It may take a few days.
Now, once you see on the edge of that cut stem a callus forming, that tells you that the conditions are right for making roots. It's at that point where it's a good idea to add your root stimulants. I like to mix up concentrated root stimulants that have kelp extract. Remember to have the humic and fulvic acid, maybe a little amino acids. I mix it up in a concentrated form, though, and then I squirt it directly onto the bare stems because then it's more concentrated. It tells the plant to make more roots.
So the rooting hormone just pushes the doorbell and says make roots. The root stimulant is only effective once you have some roots appearing. It tells the plant to make more roots for more lateral root growth and more root mass. So spray it directly on, let it drip into your clone machine into a less concentrated form that's recommended from the beginning, and then walk away.
Don't even look at the plants again for at least four or five days. It's very tempting for us to want to open it up, pull up the plant, and see if it has roots yet. But every time you lift up that plant, you disturb the microscopic root hairs. You put it back down, and the plant could stall. It could literally stall for two or three days. So be patient; let nature take its course.
I like to, once I add the root stimulant, walk away. I won't even look at my plants for at least a few days. But then when I finally come back, open up the clone machine, it's full of snowy white feathery roots.
Here are a few other factors that influence cloning success. First of all, take your cutting from the lower to middle branches, not from the growing tip. The growing tip are net importers of carbohydrates; the battery isn't all the way charged. It'll root, but it'll take a lot longer to root. But if you take the cutting from the middle to lower branches, those are net exporters of carbohydrates. They're older material, so the battery is charged. You'll get better results.
Next, take the cutting from the young vegetative part of the plant. Don't cut too far down on the branch where it's woody. That woody part is dead wood; you're not going to get good roots. So take your cutting from the low to medium branches, but from the green new growth on those branches. If possible, try to root at least two nodes instead of just one.
That's why it's so important to have proper plant nutrition for your mother plants, so you can have that nice two-inch internodal length all the way on the branch with smaller cells, thicker cell walls, and more stored energy. So if you have those healthy plants, healthy clones, and you take that cutting, you can root two nodes instead of one. You can double your roots.
Another thing I like about the clone machine is it's very friendly for being able to root more than one node. Some of the other growing mediums won't go deep enough, but if you have a stretchy plant with six-inch internodal length, you don't have any other choice but to do one node. So again, proper plant nutrition with your mother plant nutrients and your foliar sprays help pull the nutrients into the tissue. Tighter internodal length doubles your roots.
Another good tip is to make sure your mother plant is turgid before you take your cutting. If it's wilting, it's not a good time to take a cutting. So water your mother plant thoroughly at least a couple of hours before you take your cutting, so everything is nice and turgid. Think about it as filling up your canteen before you go into the desert. When you take that cutting, it's going into the desert; it has no roots. It has to depend on the stored water, stored sugar, and stored minerals from the mother plant.
So if it's turgid, you're going to have a better chance of it being able to survive until it makes the roots. Also, it's a really good idea to mist those cuttings when you take them the first time or put them into a humidity dome. That keeps the relative humidity much higher; they're much less likely to start to wilt from the heat and from the dryness of the air.
Another tip: if you have your choice, it's better to take your cuttings at the end of the light cycle instead of first thing in the morning. Now, commercial growers, commercial propagators in, say, the Philippines, would rather take cuttings at the end of the day, store them in the refrigerator overnight, and ship them out the next day. They get better results than taking cuttings in the morning and shipping them out immediately.
The reason is that during the day, when the lights are on, the plants are doing photosynthesis. They're starting to accumulate sugars all day long and storing it as starches in the leaf tissue. Now, during the night, they continue to burn some of those storage starches and reduce the amount of the bricks, the stored amount.
Now, I'm not recommending if you're doing this at home that you take the cutting and then put it in the refrigerator. No, take it at the end of the light cycle and then put it into your clone machine or into your growing medium immediately. The battery will be fully charged; you're going to get better results and faster rooting.
Next, maintain high humidity, like we talked about a few minutes ago. The humidity dome, maybe misting, and moderate temperatures. Don't cook your poor clones under high-intensity light. All you need is some mild light, just enough to stimulate photosynthesis to make new roots. I've seen that very often where it's just too hot, and we're cooking our clones.
Personally, I like to have a propagation station. So I'll have shelves with fluorescent lights on them. The bottom shelf, I put my clone machine, my aeroponic system. It has the lights above it. The next shelf gets the benefit of the heat from the lower lights, just enough temperature to help with the rooting process and the transplant process.
Up at the top, though, if I'm starting new seeds, I use the heat mats because the heat's going to go all the way up. So the warmest part is going to be at the top of my propagation station. The coolest part is going to be at the bottom, and in the middle, it's going to be moderate temperatures, which are perfect for propagation.
Speaking of lighting, use full-spectrum light. I like to keep it on 18 to 24 hours a day until the plants have rooted. Once the clones have rooted, I can cut back my lighting to 14, 16, or 18 hours. If you do over 17 hours a day of light once they're starting to root, you're probably wasting a little bit of electricity. But early on, I want to give them all the advantages they possibly can have at the start of their life.
Now, once they develop strong roots and once they're actively growing, they can adapt to their environment much more easily. So moderate temperatures and full-spectrum light with the red and blue end of the spectrum keeps tighter nodes, stronger cells, and more stored energy in those young baby plants.
Next, maintain the proper environment. Once you remove the humidity dome, have a little bit of air movement. That's healthy for the plant; it'll exercise the plant a little bit. It'll blow away like a fine breeze some of the excess moisture. It'll help protect the plant from powdery mildew and fungal attack.
So just a nice gentle environment, mild nutrients at that time as well. Just a little bit of minerals. If you over-fertilize, especially early on, the outside of the roots will be saltier than the inside of the roots. It'll pull the water out of the plant, and the clone will start to wilt. So a mild nutrient is all you need at that point.
Watch your water temperature as well. Your bottom temperature—if the water is too warm, it won't hold enough dissolved oxygen. I've seen plants growing in clone machines that have very slimy brown roots because the temperatures were too high. So maintain a mild temperature somewhere between 68 and 75 degrees. All the minerals will be available, and the cell metabolism of the root cells will be accelerated.
But you'll have healthier roots with no chance of having root rot. Remember, root rots are anaerobic fungi; they grow in stagnant water without oxygen. So if the temperatures are too warm, there won't be enough oxygen for cellular metabolism.
Finally, be patient; let nature take its course. You can't hurry the process. If you've done everything you can, nature will finish it on its own. It doesn't need your help anymore. Just be patient and wait until you have strong rooting, and then you can transplant into any growing medium you want. You'll start your plants with a strong head start.
Thanks for attending today's class on tips for successful cloning. I hope you can apply what you've learned today to grow the best of the best in your garden.