
HIGH-FREQUENCY FERTIGATION RECIPE FOR WEEKS 1-9 OF FLOWERING CANNABIS
Oct 6, 2024
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High-frequency fertigation is an excellent method for delivering consistent nutrients and water to your cannabis plants, leading to faster growth and improved yields. It involves splitting the daily required volume of water and nutrients into smaller, more frequent doses. This process keeps the growing medium moist, prevents nutrient imbalances, and maintains oxygen availability in the root zone. Here's how to apply this technique throughout the flowering cycle:
Fertigation Strategy for Flowering (Weeks 1-9)
Watering Volume Per Day:
Each plant in a 2-gallon container should receive 1-1.5 gallons of water daily, broken into multiple feeds. For a 12-plant setup in a 32 sq ft grow area, the total water required is 12-18 gallons daily.
Watering Frequency:
For high-frequency fertigation, split this total volume into 4-6 watering cycles per day, ensuring each cycle delivers between 0.25-0.4 gallons per plant per session.
Ensure 10-20% runoff with each watering cycle to prevent salt buildup in the growing medium (coco coir, due to its drainage properties, is ideal for this approach).
Crop Steering Recipe Breakdown
Nutrient Solution for Flowering (Per Gallon):
Base Nutrients (A+B formula):
Coco-specific nutrients like Canna Coco or Flora Trio are preferred. Use 8 mL per gallon (split into Part A and Part B, typically 4 mL each).
Cal-Mag Supplement:
Since coco coir tends to bind calcium and magnesium, add 3 mL of Cal-Mag per gallon.
PK Booster (Phosphorus and Potassium):
Starting mid-flowering (around weeks 3-4), introduce a PK booster at 2 mL per gallon to encourage more vital bud development and density.
Ideal pH and EC Levels:
pH Range for Coco: Maintain a pH of 5.8-6.0 to ensure proper nutrient uptake during flowering.
EC Levels:
Early to Mid Flowering (Weeks 1-6): Aim for an EC of 1.6-1.8 mS/cm to avoid overfeeding while supporting early bud growth.
Late Flowering (Weeks 7-9): Increase EC to 1.8-2.2 mS/cm as plants demand more nutrients in the final flowering stages.
Weekly Fertigation Schedule (For 32 sq ft with 12 Plants):
Stage | Number of Waterings Per Day | Water Per Session (Gallons Per Plant) | Total Daily Water Volume (for 12 Plants) | pH | EC (mS/cm) | Runoff % |
Weeks 1-3 (Early) | 4-5 | 0.24-0.3 | 12-15 gallons | 5.8-6.0 | 1.6-1.8 | 10-15% |
Weeks 4-6 (Mid) | 4-6 | 0.24-0.3 | 12-18 gallons | 5.8-6.0 | 1.8-2.0 | 10-20% |
Weeks 7-9 (Late) | 5-6 | 0.24-0.4 | 12-18 gallons | 5.8-6.0 | 2.0-2.2 | 10-20% |
Crop Steering Considerations:
Generative vs. Vegetative Steering:
To push the plant towards generative growth (flowering), decrease the volume of each watering cycle slightly and increase the EC. This signals the plant to focus more energy on bud formation rather than vegetative growth.
Light and CO2 Adjustments:
Adjust PPFD and CO2 levels in tandem with nutrient delivery:
Weeks 1-3: Start with 300-600 µmol/m²/s PPFD and 800-1000 ppm CO2.
Weeks 4-6: Increase to 600-900 µmol/m²/s PPFD and 1000-1200 ppm CO2.
Weeks 7-9: Push to 900-1200 µmol/m²/s PPFD and reduce CO2 gradually to 800-1000 ppm as plants prepare for harvest.
Sources:
Claybourne Co. Cannabis. (2023) Crop Steering Cannabis Plants.
Grow Weed Easy. (2024) High-Frequency Fertigation for Cannabis.
Royal Queen Seeds. (2023) Fertigation in Cannabis Growing.
Coco For Cannabis. (2024) Watering Coco: High-Frequency Fertigation.
This fertigation and crop steering schedule should maximize growth and bud production while minimizing stress, ensuring a robust and high-quality cannabis harvest.