DISCLAIMER: Cannabis cultivation is illegal in many jurisdictions. This content is provided for educational purposes only. Always research and comply with your local laws and regulations before cultivating cannabis. Unauthorized cultivation may result in legal penalties.
¶ Plant Training Techniques
Cannabis plants naturally grow in a conical shape (apical dominance) with one main central cola and diminishing lower branches. In indoor growing spaces, this natural shape wastes light and space. Training techniques manipulate plant structure to create an even canopy that maximizes light utilization and yield per square foot.
Key Principle: The goal of training is to convert a single dominant cola into multiple equal-sized bud sites spread across an even canopy. This can increase yields by 40-100% in the same footprint.
¶ Training Categories
| Category | Description | Stress Level | Best For |
|---|---|---|---|
| High-Stress Training (HST) | Involves cutting or damaging plant tissue | High | Healthy vegetative plants; experienced growers |
| Low-Stress Training (LST) | Bending and tying without cutting | Low | All plants; beginners; autoflowers |
| Support Techniques | Trellising, defoliation, tucking | Low to Moderate | All grows; canopy management |
¶ High-Stress Training (HST)
¶ Topping
The most common HST technique. The main stem's growing tip is removed, forcing the plant to grow two main colas instead of one.
How to top:
- Timing: Wait until the plant has 4-6 nodes (typically 3-4 weeks into vegetative growth)
- Sterilize: Use clean, sterilized scissors or pruning shears
- Locate the node: Find the topmost node (where branches meet the stem)
- Cut: Make a clean cut approximately 1/4 to 1/2 inch above the next node down
- Aftercare: The plant may pause growth for 3-7 days while it redirects energy
Results: The two branches below the cut become dual main colas. Each can be topped again for 4, then 8 main colas.
Topping Schedule:
| Topping Round | Nodes Present | Resulting Main Colas | Recovery Time |
|---|---|---|---|
| 1st Top | 4-6 nodes | 2 main colas | 5-7 days |
| 2nd Top (on each branch) | 3-4 nodes per branch | 4 main colas | 5-7 days |
| 3rd Top (on each branch) | 3-4 nodes per branch | 8 main colas | 7-10 days |
Warning: Each topping round adds recovery time. For a 4-week vegetative period, 1-2 topping rounds is realistic. More rounds require longer vegetative growth.
¶ FIMing
FIM (F***, I Missed) is a variation of topping where approximately 75% of the growing tip is removed rather than a clean cut at the node.
How to FIM:
- Locate the newest growth tip (the very top cluster of small leaves)
- Pinch or cut approximately 75% of this growth tip, leaving small portions on each side
- The remaining tissue develops into 3-4+ new growth tips rather than 2
| Factor | Topping | FIMing |
|---|---|---|
| Branches Created | 2 (predictable) | 3-4+ (variable) |
| Recovery Time | 5-7 days | 7-10 days |
| Predictability | High | Variable |
| Stress Level | Moderate | Higher |
| Best For | Consistent results | Experimentation; maximizing colas |
¶ Main-Lining
Main-lining (or manifold training) combines topping with LST to create a perfectly symmetrical plant with 8 or 16 equal main colas.
Main-Lining Steps:
- Top the plant at the 3rd node
- Wait for two new branches to develop (5-7 days)
- LST both branches horizontally, training them outward
- Top each branch again when it has 3-4 nodes (now 4 branches)
- LST all four branches outward
- Top each of the four branches again (now 8 branches)
- Let grow into flowering; optionally top again for 16 colas
- Switch to 12/12 and allow the 8-16 colas to flower evenly
Main-Lining Pros and Cons:
| Pros | Cons |
|---|---|
| Extremely even canopy | Requires 6-8+ weeks of vegetative growth |
| Predictable results | Not practical for short veg cycles |
| Maximizes light utilization | High stress; only for healthy plants |
| Excellent for ScrOG setups | Not suitable for autoflowers |
¶ Defoliation
Strategic removal of select fan leaves to improve light penetration and airflow through the canopy.
When to defoliate:
| Timing | Purpose | How Much |
|---|---|---|
| Late Veg (before flip) | Open canopy for flowering light | Remove large leaves blocking bud sites |
| Day 21 of Flower (after stretch) | Remove shaded leaves that won't contribute | Remove small inner growth; keep healthy fan leaves |
| As needed | Remove damaged, diseased, or dying leaves | Only affected leaves |
Defoliation Guidelines:
- Never remove more than 20-25% of foliage at once
- Only remove leaves that are shaded (they consume more energy than they produce)
- Never defoliate seedlings or stressed plants
- Fan leaves are nutrient factories -- healthy, sunlit fan leaves should be preserved
- During late flowering (weeks 6+), avoid defoliation
¶ Super-Cropping
A technique involving controlled stem damage to create bends that lower branch height and increase hormone concentration at the bend site.
How to super-crop:
- Select a branch that is growing too tall
- Pinch the branch between thumb and forefinger at the desired bend point
- Apply gentle pressure and roll the stem until you feel the inner fibers soften (not snap)
- Bend the branch to the desired angle
- The outer stem layer should remain intact; only the inner tissue is damaged
- Secure the branch in its new position with a tie if needed
- The plant will heal the bend into a thickened, reinforced knuckle within 3-5 days
Warning: If the stem breaks completely (outer layer tears), tape the break with grafting tape or electrical tape. Most plants will recover, but the recovery time is longer.
¶ Low-Stress Training (LST)
LST is the safest and most universally applicable training method. It involves bending and tying branches to create an even canopy without cutting or damaging the plant.
¶ Bending and Tying
Basic LST technique:
- Start early -- Begin when the plant has 4-5 nodes and branches are still flexible (2-3 weeks into veg)
- Tie down -- Use soft plant ties, garden wire, or string to gently pull branches down and outward
- Anchor -- Tie to the pot rim, trellis netting, or eye hooks
- Maintain -- Adjust ties every 2-3 days as branches grow and thicken
- Continue -- Keep training through late veg; stop 1-2 weeks before flowering flip
Key principles:
- Bend branches below the level of the main cola to equalize hormone distribution
- Be gentle -- branches can snap if bent too sharply
- Ties should be loose enough to allow stem thickening but tight enough to hold position
¶ Screen of Green (ScrOG)
ScrOG uses a horizontal trellis net to create an entirely flat, even canopy.
ScrOG Setup:
| Component | Specification |
|---|---|
| Screen | Trellis netting with 4x4 to 6x6 inch squares |
| Height | 8-16 inches above the pot/soil surface |
| Installation | Stretched horizontally across the canopy; secured at all four corners |
| Plant Count | 1-2 plants for 4x4 screen; more is unnecessary |
ScrOG Process:
- Install the screen when plants are approximately 6 inches tall (2-3 weeks into veg)
- Weave branches through the screen openings as they grow
- Tuck growing tips under adjacent screen squares
- Continue tucking every 2-3 days through vegetative growth
- Stop tucking when the screen is approximately 70% filled (the plant will continue growing 50-100% during the flowering stretch)
- Switch to 12/12 when the desired fill is achieved
- Remove any growth below the screen ("popcorn" buds) after the stretch
ScrOG Pros and Cons:
| Pros | Cons |
|---|---|
| Maximum light utilization | Requires skill and patience |
| Excellent yields per square foot | Difficult to manage pests/diseases under screen |
| Works with minimal plant count | Not ideal for strains with long internodal spacing |
| Even bud development | Screen removal at harvest can be messy |
¶ Sea of Green (SOG)
SOG uses many small plants, flowered early, to create a "sea" of single large colas.
SOG Method:
| Parameter | Specification |
|---|---|
| Plant Count | 1-4 plants per square foot |
| Vegetative Time | 1-2 weeks (minimal) |
| Training | None or minimal LST |
| Colas Per Plant | 1 main cola |
| Total Colas | Many small colas = 1 large yield |
SOG Pros and Cons:
| Pros | Cons |
|---|---|
| Fastest harvest cycle | Requires many plants (seeds/clones) |
| Simple technique | Not legal where plant count is limited |
| Good for small strains | Difficult to inspect individual plants |
| High turnover | Root space per plant is limited |
Note: SOG may not be practical where legal plant counts are limited (e.g., 4-6 plants maximum). It is most common in commercial operations or jurisdictions with generous plant limits.
¶ Training for Autoflowers
Autoflowering plants have a fixed life cycle (typically 70-90 days from seed to harvest) and less time to recover from stress. Training must be gentler.
¶ Recommended Autoflower Techniques
| Technique | Suitable for Autos? | Notes |
|---|---|---|
| LST (gentle bending) | Yes, recommended | Start early (day 14-18); very gentle bends |
| Tucking | Yes | Weave branches without tying; zero stress |
| Defoliation (minimal) | Yes, cautiously | Remove only clearly shaded leaves; never more than 10-15% |
| Topping | Generally not recommended | Only for experienced growers with long-cycle autos (85+ days) |
| FIMing | Not recommended | Too stressful for the short life cycle |
| Main-Lining | Not recommended | Requires too much vegetative time |
| Super-Cropping | Not recommended | Too stressful; recovery time exceeds benefit |
| ScrOG (light) | Possible | Use wider net spacing; minimal tucking |
¶ Autoflower LST Timeline
| Day | Action |
|---|---|
| 10-14 | First gentle bends; tie down tallest branches |
| 17-21 | Second round of bends; open the canopy |
| 21-25 | Final adjustments; stop training |
| 25-30 | Auto begins flowering; no further training |
Rule of Thumb: With autoflowers, less is more. Gentle LST can increase yields by 20-40%, while heavy HST can reduce yields if recovery time eats into the flowering period.
¶ Technique Comparison
| Technique | Stress Level | Yield Impact | Difficulty | Best Timing | Recovery Time | Suitable for Autos? |
|---|---|---|---|---|---|---|
| Topping | High | +20-40% | Easy | Veg (3-4 weeks in) | 5-7 days | No (usually) |
| FIMing | High | +30-60% | Moderate | Veg (3-4 weeks in) | 7-10 days | No |
| Main-Lining | Very High | +40-80% | Advanced | Veg (6-8 weeks) | 2-3 weeks total | No |
| Defoliation | Moderate | +10-20% | Easy | Late veg / Day 21 flower | 2-4 days | Minimal only |
| Super-Cropping | High | +15-30% | Moderate | Mid-late veg | 5-7 days | No |
| LST | Low | +20-50% | Easy | Early-late veg | 1-2 days | Yes |
| ScrOG | Low | +40-100% | Moderate | Veg through early flower | 1-2 days | Light version only |
| SOG | Low | +20-40% (per sq ft) | Easy | 1-2 weeks veg, then flip | None | Not applicable |
¶ When to Avoid Training
Training is not always appropriate. Avoid training in these situations:
| Situation | Reason | Alternative |
|---|---|---|
| Seedlings (under 3 weeks) | Too young; insufficient tissue | Wait until 4+ nodes |
| Stressed plants (heat, transplant, nutrient issues) | Additional stress compounds problems | Resolve stress first; wait 1 week after recovery |
| Flowering plants (past week 3) | Training during flower disrupts bud development | Tucking and minimal defoliation only |
| Autoflowers (HST methods) | Insufficient recovery time | Use gentle LST only |
| Weak or stunted plants | Training further reduces vigor | Focus on health first |
| Last 3-4 weeks of flower | Buds are heavy; stems are brittle | Support with trellis; no training |
¶ Tools for Training
| Tool | Purpose | Notes |
|---|---|---|
| Soft Plant Ties | LST ties; gentle on stems | Velcro plant ties or silicone-coated wire |
| Trellis Netting | ScrOG; bud support during flower | Reusable; cut to size |
| Pruning Shears | Topping; defoliation | Clean and sterilize between plants |
| Garden Wire | LST (coated only) | Use plant-safe coated wire; bare wire can cut into stems |
| Toothpicks/Skewers | Super-cropping leverage | Insert into soil as anchor points for ties |
| Grafting Tape | Repairing broken stems | Used when super-cropping goes wrong |
¶ Related Pages
- Advanced Cultivation Techniques -- Monster cropping, multi-layer SCROG, Schwazzing defoliation, multi-bend supercropping, training recovery, and optimal technique sequences
- Indoor Grow Guide -- Complete indoor grow with week-by-week training timeline and technique selection by grow stage
- Outdoor Grow Guide -- Complete outdoor grow with training for sun-grown plants and trellis netting setup
- Indoor Growing -- Training is especially valuable in space-limited indoor environments
- Lighting Systems -- Training maximizes light utilization across the canopy
- Greenhouse Cultivation -- ScrOG and LST are effective in greenhouse settings
- Pest & Disease Management -- Open canopies from training improve airflow and reduce disease risk
- Harvesting & Drying -- Training affects harvest structure and trimming
- Strains -- Strain-specific response to training varies; sativas respond differently than indicas
See Also: /cultivation/indoor | /cultivation/indoor/lighting | /cultivation/greenhouse | /cultivation/pests-diseases | /cultivation/harvest-dry | /strains