Cut your clones at a 45-degree angle on the stem, about a quarter inch below a node, which is the small bump or joint where leaves or branches emerge from the main stem. This spot has the highest concentration of the hormones and undifferentiated cells that will eventually become roots. Getting the location and angle right makes a real difference in how fast your clones root and whether they survive at all.
Why the Node Matters
Nodes are the joints along a plant’s stem where leaves, branches, and aerial roots grow out. Between two nodes is a smooth stretch of stem called the internode. The node is where you want roots to form, and biology is on your side there: nodes contain a natural buildup of auxin, the plant hormone that drives root development. Auxin concentrations at nodes help signal undifferentiated cells to specialize into root tissue. Cut too far into the internode, away from a node, and you’re working with stem tissue that has far less rooting potential.
When you make your cut, aim for roughly a quarter inch (5-7 mm) below the node. This gives the node itself a small buffer of stem tissue to draw moisture from while leaving the hormone-rich zone intact. If you cut right through the node, you risk damaging the very cells you need. If you cut an inch or more below it, rooting slows down significantly.
The 45-Degree Angle
A straight, flat cut across the stem might seem simpler, but angling your blade at 45 degrees has two real advantages. First, it exposes more of the stem’s inner tissue to water and rooting hormone, increasing the surface area where roots can emerge. Second, and less obvious, the angle changes how the cut heals. When a plant forms callus tissue (the initial wound-healing growth that precedes roots), it grows perpendicular to the cut surface. On a flat cut, callus has to travel from the outer edges all the way to the center to seal the wound. On an angled cut, the callus from the high side of the angle can overgrow the wound much faster, creating a protective barrier more efficiently.
The angle also redirects drying. Moisture loss at the cut surface moves perpendicular to the plane of the wound. On a flat cut, that drying pushes straight down into the center of the stem, potentially damaging the tissue nearest the node. On an angled cut, the drying deflects to one side, away from the node and the main water-conducting pathways inside the stem. You’re essentially steering the damage away from the parts of the cutting that need to stay alive.
How Long Should a Clone Be
For most growers, cuttings between 7 and 9 inches (18-23 cm) long hit the sweet spot. This length gives the clone enough stored energy and leaf surface to sustain itself while roots develop, without being so large that it wilts from water loss before it can root. Clones shorter than about 4 inches tend to root slowly and grow sluggishly afterward. Longer cuttings of 12 inches or more can work, especially in aeroponic cloners, but they demand more humidity control because there’s more leaf area losing moisture.
Your cutting should have at least two or three nodes above the cut point. Strip the leaves from the lowest node or two (these will be submerged in your rooting medium), and trim any large fan leaves by about half to reduce the surface area pulling water out of the stem before roots can replace it.
Which Branches to Take
There’s an ongoing debate about whether lower branches or upper growth tips make better clones. Lower branches tend to have higher concentrations of rooting hormones, since auxin is produced in growing tips and moves downward through the plant, accumulating in the lower sections. Upper branches, on the other hand, have younger, more actively dividing cells. In practice, both work. Lower branches may root slightly faster on average, while upper cuttings may produce more vigorous growth once rooted. If your mother plant is healthy and you’re cutting from actively growing stems (not old, woody ones), the difference is modest.
Clean Tools, Clean Cuts
A dull or dirty blade can crush the stem tissue instead of slicing it cleanly, and it can introduce pathogens directly into the wound. Use a sharp razor blade or scalpel rather than scissors, which pinch the stem and damage the internal water channels. Before each round of cuts, wipe your blade with 70% isopropyl alcohol, which is available at any drugstore and doesn’t need to be diluted. A 10% bleach solution (one part household bleach to nine parts water) also works but can corrode metal over time, so rinse the blade afterward.
Sterilize between plants, not just at the start of a session. If one mother plant carries a virus or fungal infection, dragging that pathogen through your cuttings on a contaminated blade can wipe out an entire batch.
What to Do Immediately After Cutting
Once you make the cut, the clock starts. The exposed stem tissue begins pulling in air instead of water, creating tiny air bubbles (emboli) that can block the stem’s internal plumbing. Get the cut end into water or your rooting medium within seconds. Some growers make their final cut with the stem submerged in water to prevent any air from entering. If you’re using a rooting gel or powder, dip the freshly cut end immediately, then place it into your medium.
For rooting medium, you have several solid options. Rockwool cubes hold moisture consistently and give the stem physical support, with near-100% success rates when humidity stays high. Aeroponic cloners, which mist the bare stems with water, produce roots faster, often within 10 days even in winter, compared to three weeks or more in perlite or peat. The tradeoff is that aero cloners need a reliable pump, and if the misting fails even briefly, unrooted clones dry out fast. Peat plugs are forgiving and simple but can take up to five weeks for slower varieties.
Humidity and Temperature for New Clones
A freshly cut clone has no roots. It’s losing water through its leaves with no way to replace it from below. This is why humidity is critical in the first week or two. Aim for about 90% relative humidity around your clones, which a simple humidity dome over a standard tray provides easily. Mist the inside of the dome once or twice a day if it dries out, but avoid soaking the leaves directly, since standing water on leaf surfaces invites mold.
Temperature should sit around 80°F (27°C). Warmer conditions speed up cell division at the cut site, encouraging faster root initiation. Below 70°F, rooting slows noticeably. Above 85°F, you risk cooking the cuttings under the dome, especially under direct light. A seedling heat mat under the tray helps in cooler environments. Keep light levels low to moderate during rooting. The clone doesn’t need intense light since it can’t absorb much water yet. Bright fluorescent or low-power LED light at 18 hours on, 6 hours off is plenty.
Once you see roots emerging from the bottom of your medium, typically 7 to 14 days depending on method and strain, you can start lowering humidity gradually over a few days. This hardens off the clone and prepares it for normal growing conditions.