There are now numerous systems available for propagating plants aeroponically from cuttings. They can be expensive, so understanding their limitations is important.
Not all plants propagate well aeroponically. Tomatoes do, many don't. Generally, plants benefit from a lower pH during propagation. A pH of 5 to 5.5 at a temperature of 72 degrees is recommended.
The aeroponic cloners I have tried instruct you run the pump continuously. Running the submersible pump continuously elevates the temperature well above 72 degrees to the peril of the cuttings. The addition of a recycle timer running 30 seconds on and 10 minutes off will greatly improve results.
It is possible the manufacturers are concerned you will balk at the price of the unit if confronted with the prospect of also purchasing an adjustable recycle timer for another $ 110.00 or so. A very nearsighted approach.
They must rely on the uninformed as potential new customers rather than referrals from successful users of their product. Arguably, the latter is a deeper more renewable source than dissatisfied and disappointed customers spreading the word.
Don't use nutrient in your cloner. Satisfactory results are to be had with tap water adjusted to the correct pH. Do change the water out after 10 to 14 days.
You will need to ask the manufacturers why they state the cuttings do not need to be covered. Manufacturers who don't offer a "dome" tend to give this advise, that may be a clue.
A trip to Staples office supplies provides an effective, inexpensive solution. Plastic cups. Place the cups over the cuttings the first 3 to 4 days in the system. A very important step to successful cloning.
There are many cloning gels and powders available. My experience is they are not helpful in the aeroponic cloner.
The aeroponic "growing" system can also be used for cloning so why not use it instead? The growing system will be larger with more space between cuttings and that is not a great use of space. It also requires a more substantial light source than cuttings in a compact area.
Simply put, the aeroponic growing system will do a fine job of cloning but if maximum production is your goal look towards a small separate area for cloning where you can run fluorescent lighting 18 to 24 hours per day. This will allow you to set your clones in anticipation of your next crop so there is no delay between harvest and setting rooted plants for your next crop.
An alternative with numerous benefits is to clone in the product "Rapid Rooters". They are available in bags of 50 for about $ 10.00 and are terrific for starting seeds or cuttings.
There is a hole drilled in the larger end of the Rapid Rooter plug which is great for planting seeds.
When starting cuttings slice the cutting diagonally about 2 inches below the top set of leaves with a razor blade. Turn the Rapid Rooter upside down (the smaller end up) and use a round tooth pick or something of similar size to make your own hole.
Store the cuttings in the refrigerator for ten minutes before inserting them in the Rapid Rooter, it will stiffen the stem making it easier to insert.
Make the hole with the tooth pick by shoving it through the Rapid Rooter. As you pull the tooth pick through from the bottom start the cutting through right behind it from the top.
Cuttings seem to do better when there is good contact with the Rapid Rooter. The pre-drilled holes are sometimes too large for the cutting to make good contact. Since the pre-drilled holes don't go all the way through you can flip the plug over and simply make your own.
Group the Rapid Rooters in an inexpensive domed grow tray (terrarium) at room temperature under a fluorescent light. The Rapid Rooters come pre-moistened. Try to keep them about the same wetness as you received them with one exception.
Add 5 drops of water where the cutting comes out immediately after insertion. The Rapid Rooters can be placed in 2 inch net pots prior to going into the terrarium or right after roots emerge when placing into your aeroponic growing system.
Rapid Rooters are my preferred propagation method.
If you have left over cuttings you can place the whole thing in potting soil and use it for a mother plant for more cuttings. Be sure to put soil all the way over the top of the Rapid Rooter so it doesn't "wick" water away from the plant.
Do not confuse Peat Pellets with Rapid Rooters. Peat Pellets are great for plants going into soil but should never be used in the aeroponic system. They can release peat particles which can plug you system.
Why clone? When you take cuttings from a female plant the resulting plant is a female identical to the mother.