The most successful and productive indoor gardeners all have one thing in common—they love cuttings! Talk to any serious grower and you’ll hear the same story. Consistently high quality and regular crops depend on a steady flow of healthy, vigorous cuttings. So it makes sense to give cuttings the best start in life possible. Too often when we visit indoor gardens we find trays of neglected cuttings, just managing to survive, relegated to a shelf in a dusty corner of the veg room. That just ain’t right! Merely keeping cuttings alive is not the aim of the game. Think of it like this … if we cause our new recruits undue stress when they are still young, fresh and fragile, it’s the botanical equivalent of dropping our babies down the stairs! Ouch! Even if they survive, they could be traumatized for the rest of their lives!

So this leads us to the question: What’s the best way to take cuttings? Enter the aeroponic cloning machine! This units aims to provide the optimal environment for your cuttings in order for them to develop roots of their own. So here’s our guide to taking aeroponic cuttings and how to give your babies the ultimate in pampering!

First let’s get some basic concepts out of the way. The whole reason you want to take cuttings in the first place is because you’ve gotten hold of something really good and you want to preserve the genetics exactly. Yes, seeds are Mother Nature’s common way of perpetuating life on this planet, but even two seeds from the same pod or packet can produce very different plants. That’s because there’s always an element of genetic randomness in gene expression. If things didn’t change from generation to generation, nothing would evolve, so it’s all good in the hood! However, sometimes we don’t want things to change. Maybe we’ve happened upon a tomato phenotype that produces prolific amounts of sweet, cherry-like fruits, bursting with unusual amounts of sweetness and flavor. Perhaps it’s the only tomato your kids will touch? Or it might be the color of fruits and flowers that floats their boat. In any case, we’re going to assume you’ve already a plant that you wish to perpetuate.

You Love Your Mother, Don’t You?

Your mother (or donor) plant is a sacred thing. Look after her! Arguably, her health represents the health of your entire garden. If your mother plant is just “doing okay” legging up in the corner of your indoor garden then it stands to reason that all cuttings taken from her will just “do okay” too—in short, they will inherit her state of health and vigor. No amount of cloning gel and aftercare is going to erase a history of neglect.

The aim of the game with mother plants is to keep them in a perpetual state of growth. (You don’t want your mother plant to flower!) The easiest way to do this for many annual plants is to ensure that irrigation cycles are regular and your lights are kept on for 15–18 hours a day. Basically you ‘trick’ your plant into believing it’s in a perpetual summer! Ask your grow store for a T5 (6500K) fluorescent fixture or a 250–400W metal halide HID grow light. Both these lights have a great spectrum (high in blue light) which encourages lots of vegetative growth.

Ideally your mother plant should be grown in an ample-sized container (at least four gallons) or, for the ultimate in Mother-love, in its own dedicated hydroponic unit. The Waterfarm by General Hydroponics is a very popular choice for maintaining a mother plant as it encourages prodigious levels of growth with very little maintenance. It’s essentially a two-gallon grow chamber sitting on top of an integral four-gallon reservoir. The grow chamber is usually filled with well-washed clay balls, and a small pump drip irrigates constantly when the lights are on. (Some growers wait until 30–60 minutes after the lights come on before commencing irrigation.) If you are using any type of dripper feed system for an extended period, make sure you regularly check for salt build-up around the drippers. Take a close look at each hole and verify that all the dripper points are actually dripping when they should be! Some growers use a small drill bit to increase the size of the holes in the dripper ring whereas others prefer to flush periodically with plain water or a low EC nutrient solution. Always use a grow formula for your nutrients but don’t over-do it (keep your mother plant as small as possible)—excessive levels of nitrogen can inhibit root development in cuttings.

Keep your mother well trained. Make sure she is regularly pruned to maintain a manageable size. As you take more and more cuttings from your mother plant, you will notice that she becomes increasingly bushy. If she becomes too bushy, start a new mother plant with a fresh cutting. Most growers tend to replace their mother plants every six months or so.

Taking cuttings is an easy concept to grasp. You’re effectively cutting off part of a plant, adapting the environment to enable it to survive without a root system, and then encouraging it to form roots of its own. Hey presto, you have another plant! A cutting is a 100% genetic copy of the mother plant, so it’s a great way of ensuring consistency from crop to crop.

Just for the record, let’s go through the (very simple) process of taking a cutting. We’ll keep things brief as, no doubt, most of you know the drill. It’s not so much the actual taking of the cutting we wish to focus on, it’s looking after them afterwards! Anyway, here we go:

How To Take a Cutting

Stem cuttings are by far the most common type of cutting that gardeners take. It involves removing some stem from a plant that contains a healthy growth tip. We’re using tomatoes for this example but this method applies to nearly all soft-wood plants.

Step 1 – Take a clean scalpel or a very sharp knife and remove a healthy looking branch from your mother plant. The sharper the blade, the cleaner the cut and the less tissue damage around it—meaning less chance of disease.

Step 2 – Remove any excess stem. Many grow guides will tell you to take a cutting at a 45 degree angle, to increase the surface area of the exposed cutting to rooting stimulators. At risk of being contentious, this really is not necessary! I actually prefer to take a ’squarer cut’ because the cut part of the stem is less susceptible to damage.

Step 3 – The more foliage on your cuttings, the more ‘life’ it has to support. It makes sense, therefore, to remove any excessive foliage. Yes, some leaves need to remain but you’re really after small, manageable cuttings that aren’t going to crowd out your propagator or cloning machine. Trim the tips of larger leaves so that the cutting is no larger than the space it is going to be given in your cloning machine. Less foliage on your cuttings makes life easier because there are fewer leaves for the cutting to support through this acutely stressful period in its life! Just as importantly, small cuttings don’t overlap each other so much, which significantly reduces the risk of mold.

Step 4 – Your cutting should look something like this. Most growers aim for cuttings between three and five inches from top to bottom. The next step is to dip your cutting into some rooting stimulator. Though not essential, rooting times will be shorter, decreasing the chance of mold or stem rot. Several compounds can be used to promote the formation of roots. They work by signaling the activity of plant hormone auxins. Among the commonly used chemicals is indole-3-butyric acid (IBA) used as a powder, liquid solution or gel. There are also cloning products on the market that use only natural ingredients. Whichever route you take (pun intended, sorry), don’t dip your cutting straight into the jar the product came in as this can lead to contamination and a far less effective product. Instead, pour a small amount into a shot glass and dip into that instead. Clean the shot glass and your blade regularly, particularly if taking cuttings from more than one mother plant. You don’t want to be transferring viruses between plants!

Okay, so now you have a freshly-taken, foliage-trimmed cutting, that’s been dipped into rooting gel or powder. It’s time to fire up your cloning machine! A timely word of advice: it’s important not to dawdle when taking cuttings! Remember, every second counts. After all, if you leave a cutting on your kitchen table, it will dehydrate and be well on the way to dying in a matter of minutes. So the sooner you can get your cutting into a propagator or cloning machine, the better. Preparation is key, especially if you are taking lots of cuttings.

Aeroponic Cuttings – Pros and Cons

Pros

1) Quicker, more vigorous rooting
2) Cleaner, so less chance of disease
3) Less maintenance
4) Reduced risk of drying out or wet / dry stress
5) No need to purchase or prepare growth media.
6) More flexibility when you choose to use your cuttings.
7) Larger cuttings can be more readily supported in aeroponic cloning machines.
Aeroponic cuttings tend to be a little hardier as they haven’t rooted inside a propagation dome.

Cons

1) Extra care needs to be taken when transferring to loose fill media.
2) Aeroponic cuttings are more sensitive to changes / extremes in temperature.
3) Increased start-up costs—unless you fashion your own machine!
4) Risk of power-cuts! A few hours of no misting can damage or kill your clones. Consider using a UPS battery back-up if power cuts are common in your area.
5) Pumps (or: The pump) and misters can be a little on the noisy side. Nothing too severe, but you wouldn’t want them in your bedroom.

Aeroponic Cloning

Fresh tomato cuttings inserted into a cloning machine. Foam disks hold the cutting firmly but gently in place.

An aeroponic cloning machine allows you to root your cuttings without the expense of buying media or the time necessary to prepare it. Typically, a submerged pump drives nutrient solution into low pressure misters. Amazingly, no humidity dome is required because the cuttings are still able to uptake any moisture they need directly from the mist. As with all equipment you use for taking cuttings, make sure your cloning machine is kept clean! Fill the machine to the indicated level with water that is at 65–68°F (18–20°C).

This low pressure mister attaches directly onto a submersible pump, creating an even mist for the cuttings. Be sure to install it so the misters point upwards.

There’s no need to add any nutrients because your cuttings don’t have roots yet! Saying this, some growers still prefer to add some hydroponic nutrients at this stage, so that as soon as the cuttings develop roots of their own, they have some immediate food available.  Hydroponic nutrients are preferable over organic nutrients as they can be immediately assimilated by your cuttings and they don’t foul up your “res.” Many growers use a very dilute version of their standard ‘bloom formulation’ because the phosphorus encourages further root development. Others prefer to use a specialist product for young plants so that the ratios of micro and macro elements are kept in balance. If you add nutrients, adjust to pH 6.0–6.3 with dilute phosphoric acid and shoot for an EC of between 0.4 and 0.6.

Room Environment

As mentioned earlier, aeroponic cloning machines don’t need humidity domes. This means it’s absolutely crucial to have your room’s environment dialed in. Your cuttings will be happiest when located in a room kept around a steady 70°F (21°C.) Try to keep room temperatures below 75°F (24°C) as excess heat just adds transpirational stress, and more stress is the last thing your cuttings want! Aim to keep the nutrient solution at 68°F (20°C); any warmer will decrease levels of dissolved oxygen in your nutrients and increase the likelihood of pathogens and stem / root rot. If your room (or nutrient solution) is too cold this will slow metabolism, shock your cuttings and inhibit that all important root development. The submerged pump will heat the nutrient solution slightly so you definitely need to keep an eye on nutrient solution temperatures. Use a nutrient thermometer to keep on top of things. If you find that the pump is warming up your nutrient solution excessively, try relocating your cloning machine on to a stone floor, lower ambient temperatures in your room if you can, or run the pump on a timer, five minutes on, five minutes off, rather than letting it run constantly. Relative humidity levels should be at least 65%. If the relative humidity in your room is less than this, you should consider misting or using a propagation dome to help increase the relative humidity directly around your cuttings.

Light Levels

Cuttings don’t require much light; in fact, high light levels are to be avoided. Remember, you want your cuttings to concentrate their energy on creating roots, not coping with an intense growing environment—that will come in time! A pair of two-foot, 55 watt, T5 fluorescent tubes hung five to eight inches away is more than enough to keep 30 or 40 cuttings very happy. Other growers will simply relegate their cloning machine to the corner of the veg chamber so that it is in the diffused light of their metal halide grow lamps. Just be sure the lights are not too intense and keep them on for 18 hours a day. Some growers prefer a 24-hour lights on approach as it makes temperatures easier to regulate, but all plants benefit from a little time out. There’s no need to overwork them! Make sure temperatures do not drop too low during the lights out period. Use a Min/Max thermometer and a thermostatically controlled heater if required, but don’t blow warm air directly on to your cuttings … ever! This will dry them out and cause them untold stress.

Insert each cutting into the center of the foam discs supplied with your cloning machine so that at least two inches of stem dangles in the misting chamber below the lid. Remember, there should not be any leaves in the misting chamber—just bare stem.

Day 1 – Settling In

Day 1 – Freshly inserted cuttings viewed as they are seen from the misting chamber.

Don’t be concerned if your cuttings wilt a little immediately after insertion into your cloning machine. They should perk up within an hour and return to looking pert. If they continue to appear limp you should try applying a very light spray with water or a dilute foliar solution with a wetting agent to help the moisture cling to the leaves. Amazingly no humidity dome is required when using aeroponic cloning machines as the cuttings are still able to uptake moisture from the misting chamber—even without roots! Your cuttings will thrive in a well ventilated but not drafty space. The last thing you want is a fan blowing on them. You shouldn’t have to do anything for the first few days—just keep an eye out for any wilting. If any cuttings don’t look happy, it’s not too late to replace them.

Day 3 – Roots start to develop

Day 3 – Cuttings start developing root calluses.

Cuttings tend to root faster in aeroponic cloning machines. It won’t be long until you see the beginning of root development. Typically this starts with the formation of small white calluses on the stem. Keep an especially watchful eye over your cuttings during the next few days. Roots should be bright white. If you observe brown or discolored roots, this could be a sign that your nutrient solution is too warm. If you haven’t done so already, it’s definitely a good idea to add some mineral nutrition to your cloning machine’s reservoir at this point as your cuttings can certainly derive benefit from it. Some growers change out the res at this stage.

Day 7 – Root Explosion!

Just 7 days after being taken, these cuttings are already bursting with root development.

With such prolific root development, it’s tempting to think the job is done, but it pays to be a little more patient before removing your cuttings from the cloning machine. This is just the ‘first generation’ of roots.

Day 8 – Secondary roots begin to develop

Day 8 – We can see the first signs of secondary root development.

As secondary roots begin to emerge, we are fast approaching the time when the cuttings will leave the cloning machine and begin life as young plants!

Day 10 / 11 – Ready and Raring to Go!

The cuttings are ready!

Lots of secondary root development and root hairs too. They are ready for transplanting.

The emergence of more secondary roots and root hairs is a sure sign that your cuttings are developed enough to handle life outside of the cloning machine. If you’re not quite ready though, don’t worry; the cuttings will be quite happy to bathe in their nutrient mist for days, even weeks if required! Just be sure to change out the nutrients once a week and keep an eye on pH levels. If roots become very long you can always trim them —they won’t mind!

Transplanting

A net pot is an ideal next stage for an aeroponic cutting. This gives you a chance to establish your cutting in the growth media of your choice. One common question about aeroponic clones is how to handle transplanting them into a pot of loose-fill media or hydroponic system. For instance, there is a common myth that aeroponic clones don’t do well in soil or coco coir. This is simply not the case; you just need to take care. Ensure your chosen media is at room temperature and fairly moist. Also, remember roots hate light, so be kind to your cuttings and transplant them away from bright lights. Partially fill the pot with media, make a hole just big enough to insert the rooted cutting, and gently back fill around it so all the roots are covered and your cutting is well supported. They will need a few days to adjust, so don’t go whacking them straight under your 1000W metal halides just yet. Ease them in gently under a 6500K T5 fluorescent or a 250W metal halide. Some growers foliar spray with sea kelp products which help to reduce stress levels. Other growers use a Victorian Bell Cloche to increase humidity levels for the first few days as the cuttings settle in.

PHOTO CREDITS: OUR BELOVED GRUBBYCUP

AEROPONIC CLONING FAQ

Here are some of the most common questions about aeroponic cloning:

1) What kind of water should be used initially to fill the res? Is regular tap ok? Or should I use distilled? Any need to pH adjust the water initially?

Regular tap water is typically fine in most major areas. It’s what I always recommend trying first. Distilled water should NOT be used, as it is so stripped of any type of mineral content that it pulls important minerals from the plant tissue hindering the initiation of root development. I often recommend users run their system without cuttings in it for the first 24 hours if they have the time. This allows them to check what their temps will be and allows some time for pH stabilization. Water should be pH adjusted after any types of solutions are added and adjusted again after cuttings have been inserted. Fill the cloning machine as high as you can so that the water level is just below the misters. The more water that is in the res, the more stable the pH and temperature.

2) Do you recommend adding anything to the water?
Yes. Use a rooting stimulator – check the label but 1 teaspoon per gallon is a general guide. Also, consider adding a silica product – this will assist in building strong cell walls and protect against bacteria etc.

3) What about adding some mineral nutrition? Should growers wait until they see roots developing? How much? And what sort of strength / pH?

I typically add nutrients only after roots have gotten between 3-4 inches in length. It’s the grower’s preference whether they go mineral (hydroponic) or organic, however I find regular hydroponic nutrients usually keeps the reservoir cleaner. I usually stay between 400-500 ppm for new clones after root development. pH between 5.8-6.3. I prefer 5.8.  I’ve also noticed that even without additives of any kind, the pH of tap water will have a tendency to rise over the course of 24-48 hours. To compensate for this, I adjust my initial pH down to approximately 5.2 because I know the pH will slowly rise somewhere close to between 5.8 and 6.3. This is an acceptable range for getting quality results. I keep the closest eye on my pH during the first 24-48 hrs. If the pH needs to be adjusted again later on, do so, but it usually stables out after the first couple adjustments. If you are not sure if you’ve got an accurate pH reading, I highly recommend getting a quality digital pH meter.

4) Veg or bloom nutrients?  Something with phosphorus (for rooting) and nitrogen?  If using GH 3-part for instance, what ratios would you use?

As long as I’m taking cuttings from a healthy Mother plant, I don’t use nutes for cloning. A cutting is developing roots because it’s searching for food. If you try to feed something that doesn’t have a mouth yet, you’re defeating the purpose. Cuttings root perfectly fine with some IBA’s and Vitamin B-1.

5) Any additives?  Either in the res or foliar?

This is a tricky topic because there are so many different additives on the market. I can’t recommend just one. We are introducing a brand new product to the market right now called EZ-CLONE Clear Rez that is designed to keep all of the internal workings of your cloner free from pathogens and promotes prolific white root growth. We’ve been testing it for over a year. It’s amazing…

6) Can you explain how root-less cuttings are still able to uptake water, with no need for humidity dome?  We’ve seen it with our own eyes, just wondered if there’s a scientific explanation.

The plant tissue still absorbs a sufficient amount of moisture for the cutting to sustain itself upright. Roots develop because the cuttings are searching for food. Humidity domes are NOT necessary with aeroponic cloners. In fact, I suspect domes help to promote airborne bacterias such as powdery mildew and prevent the cutting from transpiring naturally.

7) What are the general signs that a cutting is ready to leave the machine?

It depends what medium you’re transplanting into. I prefer to let the roots get 6-8 inches in length before transplanting into soil, coco, hydroton clay rocks, or other aeroponic systems.
The longer the roots, the better chance of your cutting surviving after its been transplanted.

Any danger signs to look out for? If root tips are slightly off color, is that okay, or a bad sign? When are nutrient temperatures definitely too high?

When res temps get above 80 degrees, cuttings are more prone to pathogens and bad bacteria. Slightly off color can be ok. If you start getting greyish/brown slime cover the bottom of your cuttings, it’s time to take precautionary measures.

9) Any general tips for transplanting aeroponic cuttings into media?

The longer the roots, the better. It’s always ok to cut excessive root growth off with sterile scissors if you’re trying to transplant a cutting into a rockwool cube or other similar medium. Most people don’t understand that this will NOT kill the cutting. Just make sure scissors are clean and always be delicate when transplanting.

10) Have you heard of growers using cloches / domes to reduce transplant stress?
Only when cuttings come from cloning methods where domes were used. When they’re cloned without domes, they transplant into domeless mediums MUCH easier.

11) Any other golden rules / tips / tricks?
We’ve kept our water temp coolest and actually saw slightly better results when putting the pump on a half hour on/ half hour off timer…a little new found info.

12) Is it necessary to change out the reservoir during one cloning cycle?
No, if everything is in proper working order, you should be able to continue using the same water for 4-6 weeks.

Everest Fernandez