Comprehensive Guide to Tackling Overwatered and Underwatered Cannabis Plants

Author Sean Prana
30 May 2023
How to diagnose, the way to restore including our top tips to help you on the way to becoming the ultimate grower.
30 May 2023
37 min read
Comprehensive Guide to Tackling Overwatered and Underwatered Cannabis Plants

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  • 1. Understanding the importance of watering cannabis plants
  • 2. Identifying signs of overwatering and underwatering
  • 2. a. Signs of overwatered cannabis plants
  • 2. b. Signs of underwatered cannabis plants
  • 3. Addressing overwatered and underwatered cannabis plants
  • 3. a. Fixing overwatered cannabis plants
  • 3. b. Fixing underwatered cannabis plants
  • 4. Optimizing your watering techniques for cannabis plants
  • 5. Understanding the role of the growing medium
  • 5. a. Soil
  • 5. b. Coco coir
  • 5. c. Hydroponics
  • 6. Role of nutrients and ph in watering practices
  • 6. a. Importance of nutrients
  • 6. b. Importance of ph
  • 7. The crucial role of roots in cannabis plant health
  • 7. a. Root health and overwatering
  • 7. b. Root health and underwatering
  • 8. Understanding cannabis plant water needs at different growth stages
  • 8. a. Seedling stage
  • 8. b. Vegetative stage
  • 8. c. Flowering stage
  • 8. d. Late flowering stage
  • 9. The role of environmental factors in watering cannabis plants
  • 9. a. Temperature
  • 9. b. Humidity
  • 9. c. Light intensity
  • 9. d. Air movement
  • 10. Advanced watering techniques for cannabis cultivation
  • 10. a. Deep watering
  • 10. b. Bottom watering
  • 10. c. Cycle watering
  • 11. Creating the ideal environment for cannabis cultivation
  • 11. a. Light
  • 11. b. Temperature
  • 11. c. Humidity
  • 11. d. Nutrients
  • 12. The significance of proper watering in enhancing cannabis yields
  • 12. a. Overwatering and yields
  • 12. b. Underwatering and yields
  • 13. The influence of water quality on cannabis plants
  • 13. a. Ph level
  • 13. b. Hardness/softness
  • 13. c. Chlorine and chloramine
  • 14. Reviving overwatered and underwatered cannabis plants
  • 14. a. Reviving overwatered plants
  • 14. b. Reviving underwatered plants
  • 15. Watering systems for cannabis cultivation
  • 15. a. Drip irrigation systems
  • 15. b. Soaker hoses
  • 15. c. Flood and drain systems
  • 15. d. Wick systems
  • 16. A comprehensive look at nutrient management in cannabis cultivation
  • 16. a. Macronutrients
  • 16. b. Micronutrients
  • 16. c. Nutrient ratios
  • 16. d. Nutrient deficiencies and toxicities
  • 17. Advanced tips for watering cannabis plants
  • 18. Final thoughts on watering practices in cannabis cultivation

Watering cannabis plants sounds like a straightforward task, but it holds immense importance and requires precision. Overwatering and underwatering can both have detrimental effects on your cannabis seeds' health and yield. This comprehensive guide will help you understand and fix these issues to ensure your plants thrive.

Understanding the Importance of Watering Cannabis Plants

Water is a crucial component in the life of any plant, including cannabis. It aids in nutrient absorption, photosynthesis, and overall growth. The right balance of water is essential - not too little and not too much.

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Identifying Signs of Overwatering and Underwatering

Before we delve into the solutions, let's first understand the signs of overwatering and underwatering in cannabis plants.

Signs of Overwatered Cannabis Plants

Overwatering is a common mistake among cannabis growers, especially beginners. Here are some signs that your cannabis plants might be getting too much water:


  • Wilting: Overwatered cannabis plants often appear wilted or droopy.
  • Yellowing leaves: Overwatered plants may exhibit yellowing leaves, especially older ones.
  • Root rot: Too much water can lead to the development of root rot, a harmful fungal disease.
  • Slow growth: Overwatered cannabis plants grow slower than their adequately watered counterparts.


How to fix overwatered and underwatered cannabis plants: Understanding the importance of watering cannabis plants

Symptoms of overwatering your cannabis plant.

Signs of Underwatered Cannabis Plants

Conversely, underwatering also poses significant risks to your cannabis plants. Look out for these signs:

  • Dry and brittle leaves: Underwatered cannabis plants may have leaves that are dry to the touch and break easily.
  • Wilting: Similar to overwatered plants, underwatered cannabis can also exhibit wilting, but the leaves often appear "crispy" or "curled up."
  • Stunted growth: Insufficient water can hinder your cannabis plants' growth and development.

Addressing Overwatered and Underwatered Cannabis Plants

Now that we understand the signs, let's delve into the solutions for overwatered and underwatered cannabis plants.

Fixing Overwatered Cannabis Plants

If your cannabis plants show signs of overwatering, here's what you can do:


  1. Decrease watering frequency: Adjust your watering schedule to allow the soil to dry out between waterings.
  2. Improve drainage: Make sure your pots have enough drainage holes. If they don't, consider repotting your plants in containers with better drainage.
  3. Use a soil mixture with good drainage properties: Consider using a soil mixture with perlite, vermiculite, or sand to improve drainage.
  4. Reduce humidity: Overwatered plants can benefit from a reduction in humidity. Consider using a dehumidifier if necessary.
  5. Address root rot: If your plants have developed root rot, consider using a fungicide or a beneficial fungus like Trichoderma to combat the disease.

Fixing Underwatered Cannabis Plants

If you suspect your cannabis plants are underwatered, consider the following steps:


  1. Increase watering frequency: Increase the frequency of watering without making the soil waterlogged.
  2. Use a soil mixture that retains water: Consider using a soil mixture with components like coco coir, peat moss, or vermiculite that retain water.
  3. Increase humidity: Underwatered plants can benefit from an increase in humidity. Consider using a humidifier if necessary.

Optimizing Your Watering Techniques for Cannabis Plants

Proper watering techniques can prevent both overwatering and underwatering issues. Here are some tips:


  • Water in the morning: Watering in the morning reduces evaporation, ensuring your plants get the most benefit.
  • Don't water on a strict schedule.


Instead, water when your plants need it. Check the moisture level of your soil before watering.


  • Water slowly: Water your plants slowly to allow the water to seep into the soil and reach the roots.
  • Water evenly: Make sure all parts of the soil get an equal amount of water to ensure the roots can access it wherever they are.

Understanding the Role of the Growing Medium

Your choice of growing medium can significantly influence your watering practices. Let's explore some common options:


Soil is the most traditional growing medium because it’s very forgiving. However, it can retain water, making overwatering a common issue. Using a well-draining soil mix and monitoring your watering habits can mitigate this.

Coco Coir

Coco coir is a popular hydroponic growing medium made from the husk of coconuts. It retains water well, reducing the risk of underwatering. However, it requires frequent watering and nutrient supplementation.


In hydroponic systems, plants grow in water rather than soil. While they offer superior nutrient and water control, they require more advanced knowledge and can be prone to issues like root rot if not managed properly.

Role of Nutrients and pH in Watering Practices

Watering isn't just about hydration. It's also an opportunity to provide your cannabis plants with essential nutrients. Furthermore, the pH of your water can affect nutrient absorption.

Importance of Nutrients

Cannabis plants require a variety of nutrients, including macronutrients (nitrogen, phosphorus, and potassium) and micronutrients (calcium, magnesium, and iron), among others. A nutrient deficiency or excess can manifest in similar ways to overwatering or underwatering, making proper nutrition vital.

Importance of pH

Cannabis plants prefer slightly acidic water, with an ideal pH range of 6.0-7.0 for soil and 5.5-6.5 for hydroponics. Outside of this range, plants may struggle to absorb nutrients, leading to deficiencies.

The Crucial Role of Roots in Cannabis Plant Health

The roots of your cannabis plants are the that supports their overall health and development. They take up water and nutrients, provide anchorage, and store food reserves. 


How to fix overwatered and underwatered cannabis plants: The crucial role of roots in cannabis plant health

Oxygen is vital for a healthy root zone!

Understanding their needs and signs of distress can greatly help in adjusting your watering practices.

Root Health and Overwatering

Overwatering can lead to waterlogged soil, causing the roots to suffocate due to a lack of oxygen. When roots can't breathe, they become susceptible to root rot, a fungal disease that can swiftly kill a cannabis plant. The signs of root rot include wilting, yellowing, and drooping leaves.

To prevent overwatering and subsequent root rot, it's vital to ensure your soil drains well. This can be achieved by adding perlite, vermiculite, or sand to your soil mix. Additionally, containers should have adequate drainage holes to allow excess water to escape.

Root Health and Underwatering

On the other hand, underwatering can cause the roots to dry out and shrink, reducing their ability to absorb water and nutrients. Symptoms of underwatering include dry, brittle leaves, wilting, and slowed growth. In severe cases, the plant may stop growing altogether.

To combat underwatering, increase your watering frequency, ensuring the soil remains moist but not waterlogged. You can also add materials like coco coir, peat moss, or vermiculite to your soil mix to help it retain moisture.

Understanding Cannabis Plant Water Needs at Different Growth Stages

Cannabis plants' water needs change as they move through different growth stages. By adjusting your watering practices accordingly, you can ensure your plants receive the right amount of water at the right time.

Seedling Stage

Cannabis seedlings have small, delicate root systems and thus require careful watering. Overwatering can easily damage these fragile roots, while underwatering can stunt their growth. Aim to keep the top inch of the soil moist at this stage.

Vegetative Stage

As cannabis plants enter the vegetative stage, their root systems expand, and their water requirements increase. However, be cautious not to overwater, as this can still cause root problems.

Flowering Stage

During this stage, plants will need more water than ever. They also require additional nutrients to support bud development. Adjust your watering and feeding schedule accordingly, ensuring the plants receive adequate hydration and nutrition.

Late Flowering Stage

In the late flowering or pre-harvest stage, you may want to reduce watering slightly. This practice, known as "flushing," can help improve the taste and quality of your buds by encouraging the plant to use up stored nutrients.

The Role of Environmental Factors in Watering Cannabis Plants

Environmental factors, such as temperature, humidity, and light intensity, can significantly affect your cannabis plants' water needs. Understanding these factors can help you fine-tune your watering practices.


High temperatures can cause water to evaporate more quickly from the soil and transpire faster from the leaves, leading to increased water needs. 


How to fix overwatered and underwatered cannabis plants: The role of environmental factors in watering cannabis plants

The temperature of the nutrient solution should also be checked.

Conversely, in cooler temperatures, water evaporation and transpiration slow down, reducing the plants' water requirements.


Humidity also plays a crucial role in plant watering. In high humidity, plants may absorb some moisture from the air, reducing their need for soil water. Conversely, in low humidity, plants may require more water.

Light Intensity

Strong light intensity can increase transpiration, leading to increased water needs. If your cannabis plants are under powerful grow lights, you may need to water them more frequently.

Air Movement

Good air movement can help regulate temperature and humidity, reducing the risk of issues like mold and mildew. However, excessive wind or fan movement can dry out plants, increasing their water requirements.

Advanced Watering Techniques for Cannabis Cultivation

To maximize your cannabis plants growth and yield, consider these advanced watering techniques:

Deep Watering

Deep watering involves watering your cannabis plants until water runs out of the bottom of the pot. This technique ensures water reaches the entire root zone, promoting healthy root development. It also helps flush out any accumulated salts in the soil.

Bottom Watering

Bottom watering is a technique where water is poured into the tray or saucer underneath the pot, allowing the plant to absorb water from the bottom up. This method can help ensure the lower root zone receives adequate moisture and can also encourage roots to grow deeper.

Cycle Watering

Cycle watering involves watering your plants in several small increments over a period of time, allowing the water to soak into the soil more thoroughly. This technique can help prevent overwatering and runoff.

Creating the Ideal Environment for Cannabis Cultivation

Creating the ideal environment for your cannabis plants involves more than just watering. Here are some additional factors to consider:


Cannabis plants require ample light to support their growth and flowering. Ensure your plants receive at least 18 hours of light during the vegetative stage and 12 hours during the flowering stage.


Cannabis plants thrive in a temperature range of 70-85°F (20-30°C) during the growing stage and 70-80°F (20-27°C) during the budding stage. Fluctuations outside of these ranges can stress your plants and affect their growth and yield.


Maintaining the correct humidity levels can significantly impact your cannabis plants' health. Aim for 40-70% relative humidity (RH) during the vegetative stage and 40-50% RH during the flowering stage.


Proper nutrition is key to your cannabis plants' health and productivity. A balanced nutrient solution containing macronutrients and micronutrients is essential. Be sure to adjust your nutrient levels according to your plants' growth stage and health.

The Significance of Proper Watering in Enhancing Cannabis Yields

Maintaining the right watering practices is not just about safeguarding your plants' health. It also significantly contributes to enhancing the final yield. Overwatered and underwatered cannabis plants are stressed plants. They spend their energy trying to survive instead of directing it toward growth and bud production.

Overwatering and Yields

Overwatered plants have their roots suffocated, preventing them from absorbing nutrients effectively. This results in slower growth rates and, in turn, smaller plants with fewer buds. Additionally, the buds of overwatered plants are often airy and lack the density of well-watered plants.

Underwatering and Yields

Underwatered plants, on the other hand, are unable to take up enough water and nutrients to support robust growth. 


How to fix overwatered and underwatered cannabis plants: Underwatering and yields

Underwatering can be as damaging and overwatering.

This results in stunted plants with fewer and smaller buds. Additionally, chronic underwatering can stress the plants, potentially triggering a survival response that leads to premature flowering and subsequently reduced yields. By carefully monitoring your plants and adjusting your watering practices as needed, you can ensure your plants are healthy, stress-free, and primed for maximum yield.

The Influence of Water Quality on Cannabis Plants

The quality of the water you use to irrigate your cannabis plants can greatly affect their health and productivity. Here are some key factors to consider:

pH Level

As mentioned earlier, cannabis prefers slightly acidic water. Water that's too alkaline or too acidic can lock out nutrients, causing deficiencies even when nutrients are abundant in the soil. Regularly test your water's pH and adjust it as needed.


Hard water contains high levels of dissolved minerals, like calcium and magnesium. While these are essential nutrients for cannabis, excess levels can lead to nutrient imbalances or lockouts. On the other hand, soft water contains few dissolved minerals, which can make your plants more susceptible to pH fluctuations.

Chlorine and Chloramine

Many municipal water supplies contain chlorine or chloramine to kill harmful bacteria. While these chemicals are generally safe for humans, they can be harmful to beneficial soil microbes and can potentially harm your cannabis plants. If your water contains these chemicals, consider using a filter or letting the water stand overnight to allow them to dissipate.

Reviving Overwatered and Underwatered Cannabis Plants

Realizing that you've overwatered or underwatered your cannabis plants can be disheartening, but don't lose hope. With the right measures, it's often possible to revive stressed plants and get them back on track.

Reviving Overwatered Plants

The first step in reviving overwatered plants is to stop watering them until the soil has dried out. You may also want to improve soil drainage by adding perlite or repotting the plant in fresh, well-draining soil. If you notice signs of root rot, consider applying a fungicide to help control the disease.

Reviving Underwatered Plants

Underwatered plants can usually be revived by gradually increasing your watering frequency. Avoid the temptation to drench the soil, as this can shock the roots and cause further damage. Instead, aim to keep the soil consistently moist. If the plant's leaves don't perk up after a few days, consider checking for root damage or a nutrient deficiency.

Watering Systems for Cannabis Cultivation

For small-scale cannabis growers, hand-watering might be feasible and even preferable, as it allows for close monitoring of each plant's individual needs. However, for larger operations or for those who prefer a more hands-off approach, various watering systems can help automate the process.

Drip Irrigation Systems

Drip irrigation systems deliver water directly to the base of your plants, reducing water waste and preventing the spread of waterborne diseases. They can be set up with a timer for automated watering and are highly customizable, making them a popular choice for many cannabis growers.

Soaker Hoses

Soaker hoses are porous hoses that "weep" water along their entire length. They can be a good choice for outdoor grows or large, linear indoor grows. They deliver water slowly and evenly, reducing the risk of overwatering.

Flood and Drain Systems

Flood and drain systems, also known as ebb and flow systems, work by flooding the grow tray with nutrient solution, then draining it back into a reservoir. This allows the roots to take up water and nutrients while also getting access to oxygen during the drain phase. These systems can be a bit more complex to set up, but they offer excellent control over watering and nutrients.

Wick Systems

Wick systems are one of the simplest types of hydroponic systems. They work by drawing nutrient solution up from a reservoir into the growing medium via a wick. This provides a steady supply of water and nutrients to the roots, reducing the risk of underwatering. However, wick systems may not provide enough water for larger, more thirsty plants.

A Comprehensive Look at Nutrient Management in Cannabis Cultivation

In addition to water, your cannabis plants need a steady supply of nutrients to thrive. Here are some key aspects of nutrient management:


Macronutrients are the elements needed in larger quantities. They include nitrogen (N), phosphorus (P), and potassium (K), often referred to as NPK, as well as secondary macronutrients: calcium (Ca), magnesium (Mg), and sulfur (S).


  • Nitrogen is essential for photosynthesis and is heavily used during the vegetative stage.
  • Phosphorus supports energy transfer in the plant and is vital for flowering and root development.
  • Potassium helps regulate plant metabolism and water uptake.
  • Calcium contributes to cell wall strength and stability.
  • Magnesium is a key component of chlorophyll, which plants need for photosynthesis.
  • Sulfur aids in the production of amino acids, proteins, enzymes, and vitamins.


Micronutrients are required in smaller quantities but are still crucial for plant health. Including boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo), and zinc (Zn).


  • Boron is crucial for cell growth and the development of plant tissues.
  • Copper aids in photosynthesis and enzyme processes.
  • Iron is a key component of many enzymes and some pigments.
  • Chloride is important for photosynthesis.
  • Manganese aids in photosynthesis and nitrogen absorption.
  • Molybdenum is essential for the process of nitrogen fixation.
  • Zinc plays a role in enzymatic reactions and protein synthesis.


How to fix overwatered and underwatered cannabis plants: Macro and micronutrients

A good combination of macro and micro nutrients is needed for optimal plant growth.

Nutrient Ratios

Different growth stages require different nutrient ratios. During the vegetative stage, cannabis plants need more nitrogen to support leaf and stem growth. As they transition to the flowering stage, they require more phosphorus and potassium to support bud development.

Nutrient Deficiencies and Toxicities

Both nutrient deficiencies and toxicities can harm your cannabis plants, leading to a range of symptoms from yellowing leaves to stunted growth. Regularly monitoring your plants and adjusting your nutrient regimen as needed can help prevent these issues. This flowchart outlines the steps involved in effective nutrient management for cannabis cultivation. Starting with assessing your plant's health, you identify its nutrient requirements, adjust nutrient ratios accordingly, monitor for any deficiencies or toxicities, and continually optimize your nutrient management practices. This cycle is integral for ensuring your cannabis plants' health and maximizing yield.

Advanced Tips for Watering Cannabis Plants

Now that we've covered the basics, let's delve into some advanced tips:


  • Use rainwater: Rainwater is naturally soft and slightly acidic, making it ideal for watering cannabis plants.
  • Consider a drip irrigation system: For larger operations, a drip irrigation system can provide precise and consistent watering.
  • Monitor your plants closely: Each cannabis strain may have slightly different watering needs. Observing your plants closely can help you cater to their unique requirements.

Final Thoughts on Watering Practices in Cannabis Cultivation

Proper watering and nutrient management are vital aspects of successful cannabis cultivation. They ensure your plants are healthy, stress-free, and can produce high-quality buds. By understanding your plants' needs and adjusting your practices as needed, you can master these aspects of cannabis cultivation.

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Remember, every cannabis plant is unique, and what works well for one might not work for another. Therefore, close observation, patience, and continual learning are the keys to becoming a successful cannabis grower. By following this comprehensive guide, you are well on your way to cultivating healthy, high-yielding cannabis plants.