How often should you water your cannabis plants?

Watering frequency for cannabis is critical to the healthy growth of your plants. Overwatering or underwatering can affect their development and productivity. In this guide, you will learn how to set the right watering schedule for your cannabis plants, considering factors such as substrate type, plant size and environmental conditions.

Factors affecting irrigation frequency

Each type of substrate has different characteristics. On the other hand, the size of the plant affects how much water it needs.

• Type of substrate
  The water holding capacity of each growing medium varies. For example, soil retains water differently than coconut fibre or rockwool. This means that if you grow in soil, the intervals between watering will be longer compared to lighter substrates such as coco fibre, which require more frequent watering.
• Plant size
  Larger plants develop roots that take up more space and require more water. A small plant in seedling stage will need less water than an adult plant in full bloom. As you observe growth, gradually adjust the amount and frequency of watering to maintain a suitable environment for the size and development of the plant. Knowing the frequency of watering for cannabis is key at every stage of cultivation.
• Ambient temperature and humidity
  The environment greatly influences the drying of the substrate. In hot, dry climates, the substrate dehydrates quickly, requiring more frequent watering. In a humid environment, the substrate stays wet longer, and excessive watering may cause moisture accumulation and affect the roots.

How to determine the ideal time to irrigate

Observing the moisture level of the substrate is the best indicator of when your plants need water.

• Finger method. Stick your finger about 2-3 cm into the soil. If it feels dry at this depth, it is time to water.
• Moisture meters. A moisture meter is an accurate tool for monitoring the moisture level in the soil, allowing you to adjust irrigation more accurately.

A simple rule of thumb is to wait until the substrate is between 3 and 4 on a scale of 1 to 10, where 1 is completely dry and 10 is saturated. Keeping the substrate slightly dry on the surface encourages oxygenation of the roots and avoids overwatering problems.

Watering frequency according to substrate type

The frequency of watering changes depending on the type of substrate you use, factors such as the type of substrate and the size of the plant influence the frequency of watering for cannabis.

• Coconut fibre and rock wool. These substrates retain less water than soil and need light, frequent watering. Watering several times a day in small amounts is more effective than applying a large volume of water. Avoid overwatering, as this can deprive the roots of oxygen and lead to disease-prone conditions.
• Land. Soil retains water longer and requires less frequent, deep watering. Watering early in the day or at most two hours before lights out is recommended, allowing the plant to absorb the water and avoid moisture accumulation during the night, when transpiration is minimal.

How much water do plants need?

The amount of water depends on the size and growth stage of the plant, to establish a watering frequency for cannabis that maintains the optimum substrate, observe these tips.

• Seedlings and young plants. They need little water, as their roots are small and can absorb sufficient moisture with moderate watering.
• Plants in advanced stages. During the vegetative and flowering phase, plants need more water to sustain growth and flower production.

A useful trick is to watch the drainage: when you water, 20-30% of the water should run out of the bottom of the container. This ensures that the entire substrate is moist and helps to remove accumulated salts and nutrients that could damage the roots.

Set up an automatic watering cycle

If you have an automatic watering system, adjust watering intervals to maintain a constant moisture level without waterlogging the substrate. Perform initial tests to see how quickly the substrate dries out between waterings and adjust the schedule accordingly. Maintaining a stable humidity ensures that plants receive water evenly without risk of oversaturation.

Find the perfect balance

Proper watering of your cannabis plants is a skill that develops with practice and observation. There are no set rules, as every environment and every plant is unique. For this reason, learning to identify the signals from your plants and substrate is key to setting an optimal watering cycle.

Remember that the aim is to keep the substrate at an ideal moisture level, promoting the absorption of nutrients and oxygen by the roots. With dedication and attention, you will master the art of watering and enjoy a healthy and vigorous crop - good luck and enjoy the process!