Monster Cropping in Outdoor Grows
Cloning flowering plants and reverting them to vegetation for outdoor gardens.
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Monster cropping works—plants do revert to vegetative growth and often develop dense branching. But the yield advantage over topped and trained vegetative plants is grower folklore, not documented science. Use it to preserve a specific phenotype from flowering or build a bushy structure early in spring. Skip it if your outdoor season is short; rooting takes weeks and clones from flower are slower to establish than vegetative cuts.
What Monster Cropping Actually Is
Monster cropping is the practice of taking cuttings from a cannabis plant already in the flowering stage, rooting them in a propagation medium, and reverting them back to vegetative growth under a long photoperiod (typically 18/6 or longer indoors, or spring/early-summer outdoor daylight).
Reverted plants display abnormal foliage during the transition: leaves may emerge with one, three, or five fingers instead of the typical seven to nine, and branching patterns are dense and erratic. Once fully re-vegetated, the plant develops a bushy, multi-headed structure with many potential bud sites.
Reversion is a well-documented horticultural phenomenon in Cannabis sativa—the plant is a facultative short-day species and can be induced back into vegetative growth by lengthening the photoperiod [1][2] Strong evidence. Cannabis can revert from flower to vegetative growth at any point if photoperiod is extended sufficiently, though success and vigor decline as the plant advances deeper into flower.
What is not well documented is the specific claim that monster cropping reliably outperforms a standard topped or Low-Stress Training (LST) plant in yield. That assertion is grower folklore Anecdote—no peer-reviewed study has compared monster-cropped outdoor plants to equally trained vegetative controls over a full season.
Why Outdoor Growers Use It
Monster cropping serves a handful of specific, practical purposes for outdoor cultivators:
Phenotype preservation late in season: If you discover an exceptional plant already in flower and did not retain a mother plant, taking flowering cuttings is the only cloning method available to replicate that exact genetics without seeds.
Creating bushy plants from an indoor mother: Cuttings taken from a flowering indoor mother in late winter or early spring will revert during the long natural daylight of spring outdoors, producing a dense, multi-branched structure suitable for SCROG, low-trellis, or LST outdoor setups before the photoperiod shortens into flowering.
Potentially shorter internodes: Anecdotal reports suggest reverted plants grow with shorter internodes and more lateral branching, which can be useful in windy outdoor locations or where space or trellis height is limited Anecdote. However, this trait is not reliably quantified in controlled studies.
**What it is not good for:** Monster cropping is a poor choice for a mid-season rescue or quick outdoor fix. Reversion takes 3–6 weeks before the plant resumes normal vegetative growth, during which it grows slowly. Clones taken from flower root more slowly and less reliably than vegetative cuttings [3] Weak / limited. If your outdoor season is short, dedicating a month to waiting for a clone to stabilize can consume much or all of your available growing window.
When to Start: Timing and Climate Windows
For outdoor growers in the Northern Hemisphere, the realistic timeline is:
Indoor mother in flower: January–March. Begin cutting during weeks 2–3 of a 12/12 light cycle.
Root and revert: 4–8 weeks indoors under 18/6 or 24/0 lighting, in a warm (22–25 °C), humid environment with low to moderate light.
Harden off: Late April–May, as outdoor daylight exceeds approximately 14 hours. Gradually acclimate the reverted plant to outdoor light and temperature.
Transplant outdoors: Once nighttime temperatures are consistently above ~10 °C (50 °F) and the local frost risk has passed.
When to avoid late cuts: Avoid taking cuttings past week 4–5 of the donor plant's flower cycle. Rooting success drops significantly as the cutting directs more resources toward bud development and less toward root initiation Weak / limited. Dense, resin-heavy upper colas root worst; prioritize lower, less-developed side branches.
In shorter or cooler climates (Canada, northern USA, Scotland), start cuts earlier (December–January) to allow extra reversion time before the outdoor season begins. In mild Mediterranean or subtropical climates, you may have a wider window (February–April) and less pressure to rush hardening-off.
How to Do It: Step by Step
- Pick a healthy donor in early flower. Weeks 2–3 of a 12/12 light cycle is the sweet spot. The donor plant should be free of heat stress, nutrient deficiency, and pest or disease signs.
- Select lower branches. Choose shoots that are 10–15 cm long, pencil-thick at the base, with at least two visible nodes. Lower branches, which are less dense with trichomes and bud material, root more reliably than dense upper colas.
- Cut at a 45° angle with sterile scissors or a scalpel, just below a node. Sterilize the blade between cuts with isopropyl alcohol or a 10% bleach solution to prevent fungal and bacterial contamination.
- Strip lower leaves and trim large fan leaves to reduce transpiration water loss. Leave 2–3 small leaves at the top for photosynthesis.
- Dip in rooting hormone. Use an indole-3-butyric acid (IBA)–based gel or powder; IBA improves adventitious root formation in many woody and herbaceous species [4] Strong evidence. Follow product label doses; overdosing IBA can inhibit rooting.
- Place in a propagation medium: Rockwool cubes (pre-soaked in pH 5.5–6.0 water), peat plugs, or an aeroponic or DWC cloner. Keep the medium temperature at 22–25 °C (72–77 °F).
- Use a humidity dome at 80–90% relative humidity for the first 7–10 days. Vent the dome daily for 30–60 seconds to prevent mold and allow gas exchange.
- Light: Provide 18/6 (or 24/0) lighting at low to moderate intensity—100–200 µmol/m²/s under fluorescent or LED. Do not apply high PPFD (photosynthetic photon flux density); reverting clones are metabolically stressed and strong light exacerbates the condition.
- Wait for rooting. Roots typically emerge in 10–21 days—considerably slower than vegetative clones. Once roots are visible (0.5–1 cm), roots are ready to pot.
- Observe reversion. Normal serrated foliage begins returning in 2–4 weeks post-rooting. At this stage, the plant is transitioning back to vegetative physiology.
- Pot up and train. Once the plant is consistently producing normal-looking leaves (7–9 fingers), pot it into a larger container with quality soil or coco mix and treat it like any other vegetative plant: top, LST, or mainline as desired.
- Harden off and transplant outdoors. When local daylight exceeds ~14 hours and remains stable, gradually introduce the plant to outdoor light and temperature (2–3 days in dappled shade, then full sun). Transplant once established and all frost risk has passed.
Common Mistakes
Taking cuts too late in flower. Past week 5, rooting success and vigor decline sharply Anecdote. Cuttings taken in late flower rarely establish vigorously, even if they do root.
Using top colas. Upper branches are dense with trichomes and bud material; they root poorly and often fail. Lower, less-developed side branches are the reliable choice.
Over-watering rooting medium. Reverting clones are slow drinkers. Soggy, oxygen-poor media cause root rot and fungal damping-off. Keep the medium moist but not waterlogged; aeration is critical.
Applying high light too early. Reverting plants are metabolically confused during the transition from flower to vegetative growth. Excessive light (>300 µmol/m²/s) stresses them further, slowing establishment. Ramp up intensity gradually as new vegetative foliage emerges.
Expecting dramatic yield gains. A monster-cropped plant given the same total vegetative time as a regular vegetative clone will not dramatically out-yield it. The yield bump people report is usually attributable to longer total veg duration and more bud sites—both achievable through standard topping and LST Disputed. This is a key source of confusion in grower reports.
Skipping quarantine and pest management. Flowering clones may carry powdery mildew, russet mites, thrips, or other pests from the flower room into your outdoor garden. Quarantine reverted plants for 1–2 weeks, inspect regularly, and treat any infestations before planting outdoors.
Planting outdoors too early. Cold-shocked reverted plants are vulnerable to slow growth and disease. Wait until nighttime lows are consistently above 10 °C and the plant is fully hardened off.
Related Techniques and Alternatives
Monster cropping is one of several high-stress and structural training methods available to outdoor growers. Consider these alternatives:
Topping: A simpler, more predictable way to produce a multi-cola plant. Vegetative topping requires no reverting phase and guarantees uniform branching from day one.
Mainlining: Mainlining creates a symmetrical manifold structure, offering better yield predictability and uniformity than monster cropping.
Low-Stress Training (LST): Gentle, reliable, and naturally suited to outdoor environments. LST produces multiple bud sites without plant stress and is less prone to failure than monster cropping.
Standard propagation: Taking vegetative cuttings from a mother plant avoids the 4–8 week reversion delay entirely, allowing faster turnaround and more predictable rooting.
If your primary goal is creating bushier outdoor plants, topping combined with LST will deliver 90% of the structural benefit with far less complexity and risk. Monster cropping earns its place only when you specifically need to clone a plant that is already in flower, or when you have an indoor mother available in winter and want to time a spring transplant to outdoor daylight.
Sources
- Peer-reviewed Moher, M., Jones, M., & Zheng, Y. (2021). Photoperiodic response of in vitro Cannabis sativa plants. HortScience, 56(1), 108–113.
- Peer-reviewed Spitzer-Rimon, B., Duchin, S., Bernstein, N., & Kamenetsky, R. (2019). Architecture and florogenesis in female Cannabis sativa plants. Frontiers in Plant Science, 10, 350.
- Peer-reviewed 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.
- Peer-reviewed Pacurar, D. I., Perrone, I., & Bellini, C. (2014). Auxin is a central player in the hormone cross-talks that control adventitious rooting. Physiologia Plantarum, 151(1), 83–96.
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