Cultivating cannabis for medical use under Canada’s Access to Cannabis for Medical Purposes Regulations (ACMPR) is a meticulous process that demands a deep understanding of horticulture. One of the most critical aspects of cannabis cultivation is watering, a seemingly simple task that, when mismanaged, can lead to poor plant health and reduced medicinal quality. This article aims to provide an in-depth guide on how to appropriately water your cannabis plants under an ACMPR license, considering various factors like water quality, scheduling, and system optimization.

ACMPR Cultivating cannabis

Importance of Proper Watering

Water is essential for various physiological processes in the cannabis plant, from nutrient transportation to photosynthesis. Proper watering is crucial for:

  1. Nutrient Uptake: Inadequate watering can impede the plant’s ability to absorb essential nutrients from the soil.
  2. Plant Health: Overwatering or underwatering can lead to root rot, nutrient imbalances, and reduced resistance to pests and diseases.
  3. Optimal Yield: Consistent watering ensures that plants grow strong and healthy, leading to better yield and quality.

ACMPR Considerations for Watering

  1. Compliance: The ACMPR requires a stable and consistent cultivation environment for medical cannabis, which indirectly implies proper watering practices.
  2. Documentation: All aspects of cultivation, including watering schedules, water source, and water quality, should be meticulously documented as per ACMPR guidelines.

Understanding Water Quality

pH Levels

  • Ideal Range: Cannabis plants generally prefer a pH range of 6.0 to 7.0 for soil grows and 5.5 to 6.5 for hydroponic systems.

Water Hardness

  • Soft vs Hard: Hard water contains more minerals that might affect nutrient uptake. Using soft water or filtered water is generally recommended.


  • Chlorine and Chloramine: These chemicals in tap water can harm beneficial microbes in the soil. Use a water filter or let the water sit to remove these chemicals.

Types of Watering Systems

  1. Hand Watering: Simple and direct, but labor-intensive.
  2. Drip Systems: Automated and efficient but can be expensive to set up.
  3. Flood and Drain Systems: Effective for hydroponic setups, but require careful timing and monitoring.

Best Practices for Watering

Watering Schedule

  • Vegetative Stage: Young plants require frequent but less abundant watering.
  • Flowering Stage: Mature plants need more water but less frequently.

Moisture Monitoring

  • Finger Test: Stick a finger an inch into the soil. If it feels dry, it’s time to water.
  • Weight Method: Lift the pot; a significantly lighter weight often indicates the need for watering.

System Maintenance

  • Check for Clogs: In automated systems, regular checks are essential to ensure all components are functioning correctly.
  • Calibration: Periodic calibration of automated systems ensures they operate within desired parameters.

Watering is a cornerstone of successful cannabis cultivation under the ACMPR license. From understanding the water quality to selecting an appropriate watering system and schedule, each step plays a crucial role in the final yield and medicinal quality of your cannabis plants. Proper documentation and compliance with ACMPR regulations add another layer of responsibility for medical cannabis cultivators. By adhering to best practices and continuously monitoring the needs of your cannabis plants, you set the stage for a successful and compliant cultivation operation, ensuring a consistent and high-quality yield suited for medical use.