Watering Woes: Over and Under Watering in Cannabis Cultivation

Watering is one of the most crucial aspects of cannabis cultivation, and yet, it’s one where both novice and experienced growers alike often encounter difficulties. This article aims to elucidate the effects, symptoms, and solutions for over and under watering cannabis plants. By understanding the significance of proper watering, growers can maximize plant health, growth, and ultimately, yield.

Understanding Cannabis Water Requirements

Cannabis, like any other plant, requires water for multiple physiological processes. Water acts as a transport medium for nutrients, enabling their uptake from the soil and their movement within the plant. It also plays a crucial role in photosynthesis and maintaining plant turgidity. The exact water requirements of cannabis plants vary depending on several factors including the growing medium, the plant’s size and stage of growth, and the environmental conditions.

Overwatering: Causes and Symptoms

Overwatering is one of the most common mistakes made by new growers. It typically stems from the mistaken belief that more water will expedite plant growth. However, overwatering can lead to a variety of issues that impede growth and damage the plant’s health.

When too much water is given to the plant, it fills the air spaces in the soil, depriving the roots of oxygen. Roots require oxygen for respiration, a process essential for energy production and nutrient uptake. In an overwatered environment, roots can become oxygen-starved, leading to stunted growth and even root death.

Overwatering often leads to telltale symptoms. The leaves of overwatered plants may appear swollen and discolored, usually a dark green. They often curl down at the edges in what’s referred to as “the claw.” Growth is typically slower, and in severe cases, overwatering can cause root rot, a condition where roots turn brown and mushy due to fungal infection.

Underwatering: Causes and Symptoms

Conversely, underwatering cannabis plants can also be detrimental. Underwatered plants receive insufficient water for optimal growth, limiting nutrient transport and photosynthesis, and reducing turgidity. An underwatered plant can appear droopy, with leaves hanging down as if wilted.

Underwatering may result from infrequent watering, inadequate water volume, or poor water retention by the growing medium. The effects are typically more immediate than overwatering, as plants rapidly lose turgidity. Symptoms include dry, brittle leaves that often yellow and curl at the edges. Growth becomes slow, and in severe cases, the plant may prematurely enter the flowering stage or die.

Striking the Right Balance: Optimal Watering Practices

Navigating the fine line between over and under watering can be challenging, particularly for new growers. It involves understanding not only the plant’s water needs but also the characteristics of the growing medium and the influence of the environment.

Assessing Water Needs

The simplest method to gauge when to water cannabis plants is the “knuckle test.” This involves inserting a finger into the soil up to the first knuckle. If the soil feels dry at that depth, it’s typically a good time to water. Additionally, the weight of the pot can provide clues. As the growing medium dries out, the pot becomes lighter.

Avoiding Overwatering and Underwatering

To avoid overwatering, it’s best to water thoroughly but less frequently. When watering, continue until you see 10-20% runoff from the bottom of the pot. This flushes out accumulated salts and ensures the entire root zone is watered. Then wait until the top inch of the soil is dry before watering again.

To prevent underwatering, it’s important to provide enough water each time. If only a small amount is given, it may not reach the deeper root zones, leading to underwatering even if performed frequently.

Adjusting to the Environment

Environmental conditions can significantly affect the plant’s water requirements. High temperatures and low humidity can increase water loss through transpiration, necessitating more frequent watering. Conversely, in cooler, high humidity conditions, water loss is reduced, and overwatering can easily occur if watering frequency isn’t adjusted.


Overwatering and underwatering are common pitfalls in cannabis cultivation, each posing a unique set of challenges and symptoms. By understanding the plant’s water needs, learning to identify symptoms of water stress, and applying appropriate watering techniques, cultivators can avoid these issues and optimize their plants’ growth and productivity. As in many aspects of cultivation, attentive observation and responsiveness to the plant’s needs are key to successful cannabis growing.

While this article provides a general overview of watering woes in cannabis cultivation, growers are encouraged to delve deeper into the topic, exploring nuances such as varying water requirements during different growth stages and the impact of various growing mediums on water retention and availability.