Tells the guru of the citrus forum, Alex:
Almost all indoor fruit plants are easily propagated by cutting, mandarin cuttings are most difficult to root, therefore, they are vaccinated when propagating.
Consider the simplest methods of cuttings. Cut the branch of the plant, which is intended for reproduction, into cuttings. To do this, make the lower section under the kidney (below the kidney by 2-3 mm), remove the lower 2 sheets, leave the next 2-3 sheets. If the leaves are very long, shorten them (cut with scissors) by 2/3 of the length. We make the upper cut 5 mm above the sheet. We cook the rest of the cuttings in the same way. Prepare a solution of root or heteroauxin, and put cuttings in it (the preparation of the solution and the processing time are indicated in the instructions).
We are preparing a greenhouse for rooting cuttings. Previously, for these purposes, I used a bottom-heated aquarium - now I use mini-bottles made from 2 liter plastic bottles (Bonacqua, Aquaminerale) in transparent and blue colors. The place where the neck of the bottle ends has a small thickening in diameter, and along this circle I cut the neck. I trim the bottom, at the bottom I make holes for moisture runoff. The neck of the bottle fits easily and firmly on the bottom. We pour expanded clay, a layer of sand on the bottom and fill almost to the edges with soil consisting of soil for citrus fruits and sand in a ratio of 1:1. Stick the cuttings 2-3 cm and water until the water protrudes onto the pallet. Drain the excess water, cover with a neck, and put in a warm, bright place. Maintain a temperature of about 25 degrees. There is no need to water during rooting. When the plants are rooted (the roots will fit the plastic and will be visible), transplant carefully into pots with a capacity of about 1 liter .
Another important point when rooting: arrange the greenhouse so that more daylight gets on the front of the sheet plates, i.e. the plate should be parallel to the glass. Light is definitely needed, the process of photosynthesis is underway. It is desirable that all leaves receive a sufficient amount of light (a handle with 3 leaves takes root faster than a handle with 1 leaf), but this is not always done - I have several cuttings in each greenhouse, all of them take root, some a little earlier, others later.
Flowering (citrus fruits often bloom on rooting) pushes back the formation of roots or they are, but develop very slowly. I have two greenhouses with lemon cuttings. One cuttings did not bloom, powerful roots are visible through plastic, and no blooming roots are observed.
The second simple way. Fill the peat pot with a 1:1 mixture of soil and sand, pour well, stick the cuttings 2-3 cm, put in a plastic bag, tie the bag and bring it to the window frame. He will not interfere with you. In rooted plants, the roots will "pierce" the peat pot and come out - this can be clearly seen through the package. Transplant the plant with a peat pot .
If moss grows on the soil surface, I occasionally remove it. To reduce the formation of algae and moss, the soil can be shaded over the surface of the plastic with a ribbon of black paper.
By the way, "naked" cuttings (without leaves) also take root. The year before last, in the fall, he put citron cuttings on rooting, some took root, and one cuttings did not want to take root. So he stood naked with me until this spring, now the root system has formed, and the first leaves have appeared.
I use heteroauxin like this: I dilute a quarter of the tablet in 50 ml of water and lower the lower sections of the cuttings there for 8 hours, then I plant the cuttings in the greenhouse. I water the planted cuttings with the remaining solution.
It is not necessary to water the cuttings in the greenhouse with a growth stimulant. If the cuttings do not take root, then they do not dry out, but usually rot, turn black or turn brown, sometimes a coating of mold appears. When rooting, look at the greenhouse more often, at the first symptoms of rot, remove the sick cuttings.
Young roots are very tender and fragile - be careful when removing cuttings from the greenhouse and planting in the ground. Cuttings with two or three leaves take root better and faster, rooting with trimmed leaves is slower, cuttings without leaves take root even slower, but they should not be thrown away either, but you need to try to root.
Better cuttings take root at a temperature of 22-25 degrees. heat in good lighting, slower at a temperature of 18-20 degrees, at a temperature below 15 degrees. most often there is decay of cuttings. Zircon did not apply and do not know its actions in practice.
Real lemons take root very easily, these include Novogruzinsky, Pavlovsky, Uralsky, Genoa, hybrids take root more difficult, it all depends on what parents the hybrids had, the most difficult rooting in mandarin cuttings, and their hybrids. Indeed, Panderosa takes root more easily than Meyer. Pasderosa is a hybrid of lemon with (presumably) grapefruit, Meyer with orange.
Rooting cuttings
Plants are rooted and it is important to preserve them after transplantation. After transplanting into separate containers, I cover the rooted cuttings with a cut neck of a plastic bottle, leave them in this form for 2-3 weeks to increase humidity inside the structure and for more comfortable conditions for the development of roots. Then I turn off the cork, in this form I can withstand another week. The next stage of adaptation is to shelter the handle for several days with the neck of a bottle with a cut neck and for several more days it is in a cylinder cut from the middle of the bottle. After these events, the handle is completely accustomed to growing in indoor conditions.
Rooting lemon in water
Says one of the forum participants, Valery:
I take a 250 ml bottle (clear glass) with a threaded neck. I take the lid from the plastic bottle (it twists well on the old bottle), in which I make a hole for the handle (or a group of cuttings). I fill the bottle with well-maintained water. At the top of the bottle I attach (with tape or duct tape) a small wire frame. From the base of the handle, along the stem, I make four vertical incisions of the bark (evenly through 90 g.) 0.5-1.5 cm long (depending on the handle).
Immerse the wet bases of the cuttings in the root (powder) and after about 5 minutes of exposure in the air, put them (through the hole in the lid) together with the remains of the root in water. I put a polythene (transparent) bag on the frame and tie it tightly at the bottom of the bottle. I cut off the upper corner of the bag, spray (through this hole the handle) with water, inflate the bag and tightly "plug" this hole. I repeat from time to time - I spray and inflate. This structure was kept on the windowsill closer to the heating riser (winter). As a backlight, I used two Fluora L 36 W/77 and Philips TLD 36W/89 daylight lamps in turn. And the sun (a rare guest in my window) helped. In this way, I managed to root the cuttings of orange, pomegranate and 3 varieties of lemon.
When rooting with my design, I periodically spray cuttings. And every day I inflate the package with my exhalation, creating increased air pressure there. It turns out an isolated atmosphere with increased pressure. It contains excess carbon dioxide and oxygen. Increased humidity and pressure prevent the evaporation of water from the surface of the sheet - and this is important when rooting! I began to apply an isolated atmosphere with increased air pressure from my lungs when rooting in the ground.
My opinion is to root, difficult plants are better in the substrate. Water only for the well-rooted.
Orange by air extraction
One of the forum participants, tsitrys, tells:
Anticipating the death of the orange, he made an air tap 17.07.06.
15.08.06 checked for roots - there was only a coalus. Made a retract at this place.
16.10.06. Patience again was not enough: he tore the package.
The first roots appeared 
They are still very small, but for fear of breaking them, he put them in the ground. As you can see, when landing in the ground there are already branches of the 3rd order.
Its root 07.11.06.