The Pre-Flowering Phase is the transition between vegetative growth and the flowering stage. Plants enter a period of rapid stretching, and the first signs of pistils (pre-flowers) appear. This stage requires careful adjustments to light, nutrients, and environmental conditions to ensure a smooth transition into full bloom.
| Parameter | Ideal range |
| Water pH (Soil) | 6.0–6.5 |
| Water pH (Coco Coir) | 5.7–6.2 |
| Water pH (Hydroponics) | 5.5–6.0 |
| EC Soil (mS/cm) | 1.6–1.8 |
| EC Coco Coir (mS/cm) | 1.8–2.0 |
| EC Hydroponics (mS/cm) | 2.0–2.2 |
| Day Temperature (°C/°F) | 24–28°C / 75–82°F |
| Night Temperature (°C/°F) | 20–24°C / 68–75°F |
| Root Zone Temperature (°C/°F) | 20–24°C / 68–75°F |
| Leaf Surface Temperature (°C/°F) | 24–26°C / 75–78°F |
| Related Humidity (RH%) | 45–60% |
| VPD (kPa) | 1.2–1.5 |
| Optimal CO₂ (ppm) | 1200-1500 |
| PAR (μmol/m²/s) | 700–1000 |
| Lights Hrs/Day | 12/12 (Photoperiod) or unchanged |
| Light Intensity (%) | 90–100 |
| Light Distance (cm/in) | 20–40 cm / 8–16 in |
| Substrate Moisture | Alternating moist and dry periods |
| Primary Nutrients | N, P, K (high) |
| Secondary Nutrients | Ca, Mg, S (high) |
| Micronutrients | Fe, Zn, Mn, B, Cu, Mo |
| N-P-K | 3-3-3 |
| LST | ScrOG, Bending, Tying |
| HST | Super Cropping, Light Defoliation |
| Medium | Frequency | Volume (ml/L) | Runoff % |
| Soil | Every 2–3 days | 400–500 | 10–20% |
| Coco Coir | Daily | 500–600 | 20–25% |
| Hydroponics | Continuous | Maintain aeration | Ensure reservoir |
Nitrogen requirements decrease, while phosphorus and potassium uptake increase to support bud development and energy production. Secondary nutrients like calcium and magnesium remain vital to strengthen cell walls and enhance photosynthesis.
| Milestones | ⬜ | Plant height increases by 40–100% during the stretch. |
| ⬜ | Pistils (white hairs) are visible, indicating flower sites. | |
| ⬜ | Canopy evenly spread and light exposure optimised. | |
| Checklist | ⬜ | Light schedule adjusted to 12/12 for photoperiod plants. |
| ⬜ | Last low-stress training completed. | |
| ⬜ | Nutrients transitioned to bloom formulas. | |
| ⬜ | Environmental parameters fine-tuned for flowering. |
The pre-flowering phase is the transitional period where plants stretch and prepare for flowering by showing their first pistils.
Look for white pistils (hair-like structures) emerging at the nodes, indicating flower development.
Yes, for photoperiod plants, switch to a 12/12 light schedule to trigger flowering.
Transition from nitrogen-heavy feeds to bloom nutrients with higher phosphorus and potassium.
Use techniques like ScrOG, bending, or tying to control vertical growth and ensure even canopy spread.
Perform light defoliation to improve airflow and expose bud sites, but avoid heavy pruning.
Water every 3–5 days in soil or daily in coco coir, ensuring proper runoff to prevent salt buildup.
Yes, you can use low-stress training (LST) to manage canopy shape, but avoid high-stress techniques.
Plants can stretch 40–100% of their original height during this phase, depending on the strain.
Gradually reduce nitrogen and increase phosphorus and potassium over 7–10 days.
Yes, increase CO₂ levels to 800–1200 ppm to enhance stretch and bud site development.
ScrOG and light defoliation work well to manage canopy structure and improve airflow.
Yes, remove weak or shaded lower branches to focus energy on upper bud sites.
Use environmental controls like dehumidifiers, heaters, or AC to maintain stable conditions.
Yes, but introduce them gradually to avoid overloading your plants with nutrients.
