Cloning: cuttings that root every time
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Cloning: cuttings that root every time

Take cannabis cuttings that root reliably. This walks a beginner from picking a mother plant to a transplant-ready clone in 14 days.

Propagation9 diagramsPeer-reviewed · 7 sources~12 min read
In this guide
01 What cloning is and why growers do it02 The words you need before you start03 Choosing a mother and making the cut04 Rooting hormone and the cube05 Dome, humidity, temperature and light06 The 14-day routine, day by day07 Why clones fail, and the fix08 What good looks like, and what to expect
01 · Start here

What cloning is and why growers do it

A clone is a cutting taken from a living plant that grows its own roots and becomes a new, genetically identical plant. No flowers and no seeds are involved. You are rooting a piece of stem, not germinating a seed.

Cloning gives every plant in a batch the same genetics as a known, proven plant called the mother. Same genetics means the same growth speed, the same yield and the same chemistry, so the whole grow runs predictable. That predictability is why nearly every commercial grow clones rather than seeds.

A well-run propagation room roots clones at 90 to 95 percent success or better[1], with cuttings ready to transplant in about 10 to 14 days[3]. This guide assumes you have never taken a cutting before and defines every term as it appears.

From mother plant to transplant1Motherhealthy plantkept in growth→2Take cuttingclean 45° cutbelow a node→3Stick in cubeunder a humiditydome→4Roots emergeday 7–14→5Transplant~day 14
Figure 1. The whole job in five steps. Roots appear between day 7 and day 14, and the clone is ready to move on at around two weeks.[3]
Who this is for

Anyone who wants to copy a plant they like and get a uniform batch every time. Pair it with the light acclimation guide for moving fresh clones into stronger light, and the IPM hygiene guide for keeping the room clean.

02 · The vocabulary

The words you need before you start

Cloning has its own jargon, and most beginner mistakes come from not knowing what a term means. Learn these six and the step-by-step sections read plainly.

NodeThe point on a stem where leaves and side-shoots attach. New roots and new growth both come from nodes, so your cut and your rooting both depend on them.
Mother plantA plant kept permanently in vegetative (leafy) growth, never flowered, purely to supply cuttings.
Cutting / cloneThe severed shoot you are rooting. The two words mean the same thing once it is off the mother.
Rooting cubeThe rockwool or peat plug the cutting sits in while it roots. It holds water and air around the stem.
DomeThe clear plastic lid that traps humidity over the tray. Burping means lifting it briefly to swap stale air for fresh.
Hardening offOpening the dome vents in stages, then removing the dome, so the clones get used to normal room air before transplant.
Anatomy of a prepared cutting1Nodewhere roots willform→2Internodebare stembetween nodes→345° basal cutfresh, justbelow a node→4Lower leaves removedto reduce waterloss→5Fan tips trimmedto ~50–70%→6Stem in cube1.5–2.5 cm deep
Figure 2. A cutting prepared for sticking: a clean angled cut below a node, lower leaves stripped, large fan-leaf tips trimmed back, and the stem set well into the cube.
03 · The how & why

Choosing a mother and making the cut

A good clone starts with a good shoot. Pick upright shoots from the upper-to-mid canopy that are at least 3 mm thick and 15 cm long. Thicker, well-lit shoots carry more stored energy and root faster than thin, shaded interior growth[2]. Shoot thickness and leaf colour reliably predict how well a cutting will root[2].

Water the mother with half-strength nutrients the day before. This lowers the pressure inside the leaves and stems (their turgor) so the stems are less brittle and snap less when you cut them. Take cuttings at the start of the light cycle with a sterile blade, making a clean 45-degree cut just below a node, and drop each cutting straight into a holding jug of dilute solution so the cut end never sits in air.

Why a 45° cut, and why no air
  • A 45° cut exposes more surface area than a flat cut, so more cells can turn into roots.
  • If the cut end sits in air, the stem draws in an air embolism (an air bubble) that blocks water uptake. Keep the end wet from the moment it is cut.
  • Sterilize the blade between mother plants so you don't carry disease from one to the next.[7]
Where to take cuttings from on the motherIndicative rooting success by shoot origin. Firm, well-lit upper-mid shoots root best.025507510092% rootUpper-mid (best)58% rootLower interior70% rootSoft tip growth
Figure 3. Upright shoots from the well-lit upper-to-mid canopy root most reliably. Weak shaded interior growth lags well behind.[2]
04 · The how & why

Rooting hormone and the cube

Cuttings have no roots yet, so a rooting hormone pushes the stem to grow them. The active ingredient is usually IBA (indole-3-butyric acid), a synthetic version of a natural plant root hormone called an auxin[4]. Inside the stem the plant converts IBA into the active rooting auxin (IAA), which is what triggers new roots[5]. It sells as a gel or a liquid.

Make a fresh 45-degree cut right before sticking to expose new tissue, coat the bottom 1–2 cm of stem in rooting gel, and insert it 1.5–2.5 cm into a pre-soaked cube. Firm it just enough that the cube lifts with the stem when you tug gently, the lift test, but don't crush the cube.

  1. 1
    Pre-soak the cube
    Soak rockwool or peat cubes in clone feed for at least 15 minutes. Let them drain freely. Do NOT squeeze them out, or you crush the air out of them.
  2. 2
    Fresh cut
    Re-cut the stem at 45° just before sticking to open clean, un-embolised tissue.
  3. 3
    Apply hormone
    Gel: dip the cut end about 0.5 in (the lower 1–2 cm). Liquid/alcohol dip: soak the cut end about 30 seconds.
  4. 4
    Stick & lift-test
    Insert 1.5–2.5 cm deep. Tug gently: the cube should rise with the stem.
Speed matters

Keep the time from the final cut to sticking under about 30 seconds. The longer a fresh cut end sits in air, the more likely an air bubble blocks water uptake and the cutting stalls.

Hormone concentration vs rooting (typical IBA response)Rooting rises with IBA dose up to a point, then over-strong hormone burns the stem and rooting falls off.405570851000 (none)lowmediumhightoo high% rooted
Figure 4. There is a sweet spot. Too little hormone and rooting is slow. Too much scorches the stem base. Commercial gels come pre-mixed to land in the productive range.[4]
05 · The how & why

Dome, humidity, temperature and light

A cutting with no roots cannot pull water up the stem, so it survives on humidity until roots form. That is the entire point of the dome. The dome traps moisture so water enters the leaves directly from the air while the stem grows roots.

Keep the air around 24–26°C and start with very high humidity (85–95% RH) inside a closed dome, then step it down as roots develop[3]. Put a heat mat under the tray to keep the cube itself at 22–24°C. Roots form faster in warm media than in warm air, because warm roots grow quicker[6].

Keep light gentle, about 60–100 PPFD (a measure of light intensity reaching the plant) in the first days, rising toward 150–200 by hardening off[3]. Measure it with the dome in place, because the plastic cuts the light reaching the cutting underneath.

Dome humidity by rooting phaseHumidity is highest at the start and steps down as roots take over water uptake.Initial heal (d1–4)Early root (d5–7)Mid root (d8–10)Harden (d11–14)60% RH80% RH100% RH
Figure 5. Target dome humidity falls in stages across the run as the clone grows roots and can start drawing its own water.[3]
Four-phase environment targets, all at 24–26°C air and a 22–24°C cube. VPD is a combined dryness measure; higher = drier air.[3]
PhaseDaysRHVPD (kPa)Light (PPFD)
Initial healing1–485–95%0.3–0.560–100
Early rooting5–780–85%0.5–0.780–120
Mid rooting8–1070–80%0.6–0.8100–150
Hardening11–1465–75%0.8–1.0150–200
Air movement, not a fan in the face

Gentle air movement in the room is good, but never aim a fan directly at un-rooted clones. With no roots to replace lost water, a direct breeze dries them out and wilts them fast.

06 · Do this

The 14-day routine, day by day

Cloning is mostly leaving the tray alone at the right times and intervening at the right times. The schedule below is the whole job.

The 14-day arc1d1–4dome shut, notouch→2d5–7first water +open vents→3d7check for whiteroots→4d8–10prop vents wider→5d11hardening-offtest→6d14transplant
Figure 6. Closed and untouched at the start, then the dome opens in stages as roots appear and the clone learns to drink for itself.

Days 1–4: vents fully closed, do not touch. The trapped humidity makes the cutting close its leaf pores and focus on rooting. Days 5–7: the first watering usually comes due. Judge it by tray weight. Irrigate when the tray has dropped 40–50% below its Day 0 weight, and never let it fall below 30% loss, because a permanently soggy cube rots[8]. The cube fading from dark to light brown is the same signal.

Clone feed should run an EC of about 1.5 mS/cm at pH 5.5–6.0, with the water at 20–22°C. From day 7 start a daily burp, begin propping the vents open, and lift one edge cube to look for emerging white roots. On day 11 run the hardening-off test: lift the domes, wait 10 minutes, and if fewer than 5 clones per tray wilt, leave the dome off; if 5 or more wilt, re-dome and retry tomorrow. Transplant at around day 14.

Vent state across the runThe dome opens in stages from fully closed to fully off as roots establish.ClosedBurp 5–10 min/day25–50% open50–100% open1day7.5day14day
Figure 7. How far the dome vents are open by day. Closed at the start protects rootless cuttings; fully open by the end hardens them for room air.
The day-by-day routine condensed. Transplant criteria are the key go/no-go at the end.
DayWhat you doWhat you're looking for
1–4Dome shut, do not touchCuttings standing turgid, not wilting
5–7First water by weight; start opening ventsCube fading dark→light; 40–50% weight loss
7+Daily burp; lift an edge cubeFirst white roots emerging
11Hardening-off test (dome off 10 min)<5 wilting per tray → dome stays off
14Transplant the keepersRoots ≥2–3 cm on multiple sides; cube holds together
07 · When it goes wrong

Why clones fail, and the fix

Most clone failures trace to a handful of causes, and they look distinct enough to diagnose at a glance. The table below maps each symptom to its likely cause and the fix.

Diagnose by symptom, then act. Many of these overlap, so fix the most likely cause first and watch for a day.
SymptomLikely causeWhat to do
Severe wilting, days 1–2Dome RH too low / light too high / heat mat offRH ≥85%, drop PPFD, get the cube to 22–24°C
Mold or slimy cubesStanding water, poor hygiene, or too warmEmpty standing water; gloves-only handling; keep cubes <26°C
Burnt / crispy leaf tipsFeed EC or VPD too high (too dry)Drop EC 0.2–0.3, raise RH, slow the vent opening
Yellowing before rootsMother was deficient, or feed EC too lowReview mother nutrition; nudge EC up next run
White fuzzy mold in domeHumidity too high with no air exchangeBurp more often; never skip dome hygiene
Uneven / patchy rootingInconsistent cube moisture or hormoneSoak cubes evenly; consistent gel dip depth
Hygiene is non-negotiable

Disease in a propagation room spreads cutting to cutting through tools and hands. Sterilize tools for at least 2 minutes in 71% isopropyl alcohol (or chlorine dioxide for at least 180 seconds), and handle cubes with gloves only. Bare hands spread algae and pathogens[7]. Good hygiene prevents the damping-off and root-rot organisms that wipe out whole trays[7].

08 · Reality check

What good looks like, and what to expect

A realistic first goal is 90 percent rooting, with experienced rooms hitting 95 percent or higher[1]. Expect roots in 10 to 14 days, and treat anything past 21 days with no roots as a problem to escalate, not a clone to keep waiting on.

Not every cutting will make it, and that is normal. Sorting at transplant, called culling, is part of the process. Keepers have strong roots and light-green tops. Rejects rooted but only put out one to three weak roots. Kills have zero roots and get discarded. Plan for this by taking 15 to 40 percent more cuttings than the number of plants you actually need, so culls don't leave you short.

Plan for overage: a 100-plant target at 40% overTake more than you need so culling at each stage still leaves a full batch.04080120160140 plantsCuttings taken120 plantsVeg (rooted)100 plantsFlowered
Figure 8. Working back from the number you need to flower, take a healthy surplus up front so culls at rooting and veg still land you on target.
Sorting at transplant: keepers, rejects, killsA dialed room sends the large majority through as strong keepers.025507510090%Keepers6%Rejects4%Kills
Figure 9. What a good tray looks like when sorted: most cuttings are strong keepers, with a small tail of weak rejects and a few kills.[1]

Some genetics root slower. For slow-to-root cultivars, take the cuttings a few days earlier so they still hit the transplant date on schedule. Record everything, tray weights, EC and pH, success rate per batch, because clone data drives every decision downstream in the grow.

Three honest truths
  1. 90% is the floor, not the ceiling. A new grower hitting 90% is doing well; a dialed room runs 95%+. Below 80% means something in the environment or hygiene is off.
  2. Culling is success, not failure. Throwing out weak clones up front protects the uniformity of the whole batch.
  3. The environment does the work. Humidity, cube temperature and light matter more than any brand of hormone. Dial those in first.

Once your clones are rooted and hardened off, the next job is moving them into stronger light without shocking them. See the light acclimation guide. Keep the propagation room clean from day one with the IPM hygiene routine, because a clean room is most of a high success rate.

Related papers
Light acclimation
Ramp light without bleaching
IPM: pest management
Scout, decide, act
Tissue culture
Clean up genetics from a speck of tissue

References

  1. Caplan, D., Stemeroff, J., Dixon, M., & Zheng, Y. (2018). Vegetative propagation of cannabis by stem cuttings: effects of leaf number, cutting position, rooting hormone, and leaf tip removal. Canadian Journal of Plant Science, 98(5), 1126-1132. https://doi.org/10.1139/cjps-2018-0038
  2. Esposito, L.G.A., et al. (2026). Analysis of Marijuana (Cannabis sativa L.) Cuttings: Morphological and Colorimetric Traits as Predictors for Optimization of Vegetative Reproduction. Plants, 15(3), 440. https://doi.org/10.3390/plants15030440
  3. Kim, B., Hahm, S., Lee, Y.J., Bok, G., & Park, J. (2025). Light, Temperature, and Relative Humidity Influence the Adventitious Rooting of Cannabis Stem Cuttings. Horticultural Science and Technology, 43(4), 480-493. https://doi.org/10.7235/HORT.20250043
  4. Landis, H., et al. (2022). Impact of Indole-3-butyric Acid Concentration and Formulation and Propagation Environment on Rooting Success of 'I3' Hemp by Stem Cuttings. HortTechnology, 32(3), 321-330. https://doi.org/10.21273/HORTTECH05016-21
  5. Fattorini, L., Veloccia, A., Della Rovere, F., D'Angeli, S., Falasca, G., & Altamura, M.M. (2017). Indole-3-butyric acid promotes adventitious rooting in Arabidopsis thaliana thin cell layers by conversion into indole-3-acetic acid and stimulation of anthranilate synthase activity. BMC Plant Biology, 17, 121. https://doi.org/10.1186/s12870-017-1071-x
  6. Lopez, R.G., & Runkle, E.S. (2008). Photosynthetic daily light integral during propagation influences rooting and growth of cuttings and subsequent development. HortScience, 43(7), 2052-2059. https://doi.org/10.21273/HORTSCI.43.7.2052
  7. Punja, Z.K., Tirajoh, A., Collyer, D., & Ni, L. (2023). Biological control of Fusarium oxysporum causing damping-off and Pythium myriotylum causing root and crown rot on cannabis (Cannabis sativa L.) plants. Canadian Journal of Plant Pathology, 45(3), 245-264. https://doi.org/10.1080/07060661.2023.2172082
  8. Lopez, R.G. & Currey, C.J. (Michigan State University Extension). Moisture management during vegetative cutting propagation. MSU Extension / Greenhouse floriculture. (non-peer-reviewed source) https://www.canr.msu.edu/news/moisture_management_during_vegetative_cutting_propagation
  9. Liu, Y., et al. (2023). Photosynthetic Acclimation of Shade-Grown Soybean Seedlings to a High-Light Environment. Plants/Frontiers in Plant Science (shade-to-high-light photoinhibition study). https://pmc.ncbi.nlm.nih.gov/articles/PMC10305168/

Citations marked in-text as [n] map to this list. Peer-reviewed sources except where noted. Cannabis tissue culture is strongly genotype-dependent, verify dilutions, hormone doses and local regulations against the primary sources before relying on them.