Contents
Growth Stage Definitions
Standardized definitions ensure consistent communication about plant development across research and breeding programs.
Seedling and Early Vegetative Stages
| Stage | Days from Germination | Key Characteristics | Development Milestones |
|---|
| Germination | 0-3 days | Seed coat cracking, radicle emergence | Tap root 5-10mm, cotyledons still closed |
| Seedling | 3-10 days | Cotyledons open, first true leaves emerging | First set of true leaves with serrations |
| Early Vegetative | 10-30 days | 2-5 nodes, active vertical growth | Lateral branches begin forming from nodes |
| Established Vegetative | 30-60 days | 6+ nodes, branching structure | Secondary branching, established root system |
| Late Vegetative | 60+ days | Robust branching, slowing vertical growth | Pre-flower development may begin |
Flowering Stages
| Stage | Photoperiod Cannabis | Auto-flowering Cannabis | Key Characteristics |
|---|
| Pre-flowering | Week 1 after light change | Week 3-4 from germination | First pistils appear at nodes, stretch begins |
| Early Flowering | Week 1-3 | Week 4-5 from germination | Pistil clusters form, bracts develop |
| Mid Flowering | Week 3-6 | Week 5-7 from germination | Bud structures form, rapid calyx development |
| Late Flowering | Week 6-8 | Week 7-9 from germination | Bud expansion, trichome development |
| Ripening | Week 8-10+ | Week 9-11+ from germination | Trichome maturation, pistil darkening |
Vegetative Phase Metrics
Height and Structure Measurements
| Metric | Measurement Method | Typical Range | Notes |
|---|
| Plant Height | Soil surface to apical tip | 15-200+ cm | Genetic and environmental influence |
| Internodal Spacing | Distance between successive nodes | 2-10+ cm | Indicator of stretching, light conditions |
| Stem Diameter | Caliper measurement at base | 0.5-3+ cm | Indicator of structural strength |
| Node Count | Total count of stem nodes | 5-15+ | Cultivar-dependent |
| Branch Count | Total count of lateral branches | 4-20+ | Training-dependent |
| Leaf Span | Widest point of mature fan leaf | 10-25+ cm | Genetics and maturity indicator |
| Canopy Diameter | Widest point of overall canopy | 30-150+ cm | Training and space-dependent |
Leaf Development Metrics
| Metric | Description | Measurement Approach | Significance |
|---|
| Leaf Serration | Depth and number of serrations | Count and measure depth | Genetic indicator, taxonomic significance |
| Leaflet Number | Leaflets per compound leaf | Count on mature fan leaves | Age and genetic indicator |
| Leaf Color | CIELAB values or comparison chart | Colorimeter or visual reference | Nutrient status, genetics |
| Leaf Thickness | Physical measurement | Micrometer at center of blade | Vigor and environment adaptation |
| Leaf-to-Stem Ratio | Leaf mass divided by stem mass | Weight measurement after separation | Growth efficiency indicator |
Root Development Metrics
| Metric | Measurement Method | Optimal Range | Notes |
|---|
| Root Ball Diameter | Measure widest point | Container-dependent | Should reach container edges |
| Root Density | Visual rating (1-10) | 7-10 rating | White, healthy roots throughout medium |
| Root-to-Shoot Ratio | Dry weight comparison | 0.5-1.0 ratio | Balance indicator |
| Root Tip Color | Visual assessment | White/cream | Brown/dark tips indicate stress |
| Root Mass | Wet/dry weight measurement | Strain-dependent | Comparative measure between phenotypes |
Flowering Phase Metrics
Inflorescence Development
| Stage | Visual Indicators | Trichome Development | Pistil Status |
|---|
| Early (Week 1-3) | Small pistil clusters at nodes | Minimal, clear stalked trichomes | 100% white, extended |
| Formation (Week 3-4) | Distinct bud structures forming | Increasing density, still clear | 90-100% white, curling begins |
| Development (Week 4-6) | Buds gaining size and density | Capitate stalked trichomes abundant | 70-90% white, 10-30% orange |
| Bulking (Week 6-8) | Significant size increase | Cloudy trichomes dominate | 40-70% white, 30-60% orange |
| Ripening (Week 8-10) | Maximum density, some swelling | Cloudy to amber transition | 10-30% white, 70-90% darkened |
| Peak Maturity (Week 9-12) | Calyxes fully swollen | 10-30% amber trichomes | 0-20% white, mostly receded |
Trichome Assessment
| Trichome Appearance | Cannabinoid Status | Harvest Timing | Effect Profile |
|---|
| Clear/Translucent | Immature, developing | Too early | Underdeveloped, potentially stimulating |
| Milky/Cloudy | Peak THC production | Peak psychoactivity | Balanced effects, potent |
| Amber/Honey | THC degrading to CBN | Later harvest | More sedative, body effects |
| Mixed (20-30% amber) | Balanced profile | Optimal for most | Full-spectrum effects |
Inflorescence Architecture Metrics
| Metric | Measurement Method | Typical Range | Significance |
|---|
| Calyx-to-Leaf Ratio | Visual assessment (1-10) | 6-9 rating | Higher values indicate less trim work |
| Inflorescence Density | Squeeze test (1-10) | 5-9 rating | Indicator of yield and mold resistance |
| Bud Structure | Morphology classification | Foxtail, spear, round, etc. | Genetic characteristic |
| Trichome Coverage | Visual rating (1-10) | 5-10 rating | Potential potency indicator |
| Trichome Size | Microscopic measurement | 50-500µm | Genetic trait affecting resin production |
Maturity Assessment Guide
| Harvest Window | Trichome Appearance | Pistil Color | Calyx Appearance | Effect Profile |
|---|
| Early Harvest | 0-5% amber, mostly cloudy | 30-40% darkened | Slightly swollen | More cerebral, energetic |
| Peak Harvest | 10-30% amber | 70-90% darkened | Fully swollen | Balanced effects |
| Late Harvest | 30-50%+ amber | 90-100% darkened | Very swollen, some receding | More sedative, body effects |
Standardized BBCH Scale
The BBCH scale (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) provides a standardized system for describing plant growth stages across species. This adaptation for cannabis facilitates precise communication in research and breeding.
Principal Growth Stages
| Code | Description | Visual Indicators |
|---|
| 0 | Germination | Seed imbibition through cotyledon emergence |
| 1 | Leaf development | First true leaf through 9+ leaves unfolded |
| 2 | Formation of side shoots | First side shoot visible through 9+ side shoots |
| 3 | Stem elongation | Beginning of stem extension through 90% of final height |
| 5 | Inflorescence emergence | First floral structures visible through all primordia visible |
| 6 | Flowering | First flowers open through 90% of flowers open |
| 7 | Fruit/seed development | First seeds/fruits visible through advanced development |
| 8 | Ripening | Beginning of ripening through fully ripe |
| 9 | Senescence | Post-harvest maturation, dormancy, death |
Detailed Secondary Growth Stages
| Code | Description | Visual Indicators |
|---|
| 00 | Dry seed | Dormant seed |
| 03 | Radicle emergence | Seed coat cracking, radicle visible |
| 05 | Radicle 5mm | Root development begins |
| 09 | Cotyledons emerge | Breaking soil surface |
| 10 | Cotyledons completely unfolded | First true leaf visible at <1mm |
| 11 | First true leaf pair unfolded | First serrated leaves fully expanded |
| 12 | Second true leaf pair unfolded | Two nodes developed |
| 13-19 | 3rd-9th true leaf pairs | Corresponding nodes developed |
| 21-29 | Side shoots development | First through 9th side shoots visible |
| 31-39 | Stem elongation | 10%-90% of final height |
| 51 | Floral primordia visible | First pistils at nodes (pre-flowers) |
| 55 | First flower buds visible | Distinct bud formations |
| 59 | First bract with pistils visible | Flower cluster development |
| 61-69 | Flowering progression | 10%-90% of flowers with pistils |
| 71-79 | Seed/fruit development | Size progression of bracts and calyxes |
| 81 | Beginning of ripening | First trichomes cloudy |
| 85 | Advanced ripening | 50% of trichomes cloudy/amber |
| 89 | Fully ripe | Optimal harvest point for purpose |
| 92 | Over-ripening | Post-peak degradation |
| 97 | Plant death | Complete senescence |
Data Collection Methods
Measurement Frequency Guidelines
| Growth Phase | Recommended Frequency | Key Metrics to Track | Purpose |
|---|
| Seedling | Every 3-5 days | Height, node emergence, leaf development | Early vigor assessment |
| Vegetative | Weekly | Height, branching, internodal spacing | Structure development tracking |
| Early Flower | Every 5-7 days | Stretch percentage, bud site development | Transition monitoring |
| Mid Flower | Weekly | Bud development, trichome emergence | Production potential assessment |
| Late Flower | Every 3-5 days | Trichome maturity, calyx development | Harvest window determination |
| Tool | Usage | Precision | Notes |
|---|
| Measuring Tape/Ruler | Height, width, internodal spacing | ±1mm | Basic but essential |
| Digital Caliper | Stem diameter, bud dimensions | ±0.1mm | More precise measurements |
| Digital Scale | Fresh/dry weights | ±0.1g | Yield projections |
| USB Microscope | Trichome examination | 40-1000x | Maturity assessment |
| Color Chart | Leaf/pistil color assessment | Visual reference | Standardized comparisons |
| Data Logger | Environmental conditions | Varies by parameter | Correlating growth with conditions |
| Smartphone Apps | Integrated measurements | Various | Convenient but validate accuracy |
Standardized Phenotype Data Sheet Template
CANNABIS PHENOTYPE DATA SHEET
Plant ID: ________________ Cultivar: ________________ Date Started: ____________
VEGETATIVE MEASUREMENTS
-------------------------------------
| Date | Days | Height | Nodes | Internodal | Branch | Leaf | Notes |
| | | (cm) | (#) | Space (cm) | Count | Width| |
|------|------|--------|-------|------------|--------|------|-------|
| | | | | | | | |
| | | | | | | | |
FLOWERING MEASUREMENTS
-------------------------------------
| Date | Days | Height | Bud | Trichome | Pistil | Aroma | Notes |
| | (F) | (cm) | Density | Status | Color | Profile | |
|------|------|--------|--------|---------|--------|--------|-----|
| | | | | | | | |
| | | | | | | | |
HARVEST DATA
-------------------------------------
Harvest Date: _____________ Days in Flower: ________ Total Life: ________
Fresh Weight: _____________g Dry Weight: _____________g Yield Ratio: _______
Trichome Status at Harvest: _______________________________________
Aroma Profile: ________________________________________________
Effect Profile: ________________________________________________
Phenotype Evaluation
Vegetative Trait Scoring System
| Trait | Score 1 | Score 5 | Score 10 | Importance |
|---|
| Growth Rate | <1cm/day | 1-2cm/day | >2cm/day | High |
| Branching | Minimal | Moderate | Extensive | Medium-High |
| Leaf Size | Small (<10cm) | Medium (10-15cm) | Large (>15cm) | Medium |
| Node Spacing | Very tight (<1cm) | Medium (2-4cm) | Wide (>5cm) | Medium-High |
| Stem Strength | Weak, needs support | Moderate | Strong, self-supporting | High |
| Root Development | Minimal | Moderate | Extensive | High |
| Transplant Recovery | Slow (>5 days) | Moderate (2-4 days) | Rapid (<2 days) | Medium |
| Stress Tolerance | Poor | Moderate | Excellent | High |
Flowering Trait Scoring System
| Trait | Score 1 | Score 5 | Score 10 | Importance |
|---|
| Flower Onset Speed | Slow (>14 days) | Moderate (7-14 days) | Rapid (<7 days) | Medium |
| Stretch Factor | Low (<25%) | Medium (50-100%) | High (>200%) | Medium-High |
| Bud Density | Loose, airy | Moderate | Dense, compact | High |
| Trichome Coverage | Sparse | Moderate | Heavy | Very High |
| Trichome Size | Small | Medium | Large | High |
| Calyx-to-Leaf Ratio | Leafy | Moderate | Mostly calyx | High |
| Aroma Intensity | Mild | Moderate | Strong | High |
| Aroma Complexity | Simple, one-note | Moderately complex | Complex, layered | Medium-High |
| Flower Period Length | Long (>11 weeks) | Moderate (8-10 weeks) | Short (<8 weeks) | Medium |
Harvest Quality Assessment
| Trait | Measurement Method | Evaluation Criteria | Importance |
|---|
| Yield | Dry weight per plant or per m² | Comparison to standard | High |
| Bud Structure | Visual assessment | Uniformity, density, appeal | Medium-High |
| Trichome Maturity | Microscope examination | Optimal cloudy/amber ratio | Very High |
| Aroma Profile | Sensory assessment | Intensity, complexity, appeal | High |
| Moisture Content | Moisture meter or bend test | 10-12% ideal | Medium-High |
| Trim Quality | Visual inspection | Leaf remnants, manicuring | Medium |
| Cure Quality | Jar assessment | Even moisture, aroma development | High |
| Effect Profile | Testing panel | Onset, duration, character | Very High |
Note on Objective Measurements: While many assessments involve subjective scoring, using standardized references and multiple evaluators can improve consistency. When possible, supplement subjective measures with quantitative data (weights, dimensions, lab testing) for more reliable phenotype comparisons.
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