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David Rhodes

David has been working in the cannabis industry for the past 17 years with experience working overseas in Amsterdam as a budtender for 5 years! Learn More About David!

Just like various other plants, marijuana necessitates essentials like water, air, oxygen, nutrients, and so forth for growth. However, hydrating a marijuana plant isn’t straightforward as it might seem. Either too much or too little water can inhibit the plant’s growth or even cause it to die.

Overwatering Cannabis and Underwatering Cannabis

If you overwater your marijuana plants, their leaves will droop. Overwatered plants have saturated yellow curly leaves.

Leaves appear lifeless and weak if you underwater a marijuana plant. Additionally, they get brittle upon touching and simply look dry.

Are you planning to start your marijuana grow for the first time? Already have grown plants and intend to water them? Learn some watering strategies to keep your plants healthy and hydrated in the subsequent sections. No matter if you’re growing in a closet, in a greenhouse or outdoors, providing the right amount of water for your plants is essential to the success of your grow.

Why Over-Watering Your Cannabis Is Bad

Beginner and experienced cannabis growers are commonly faced with overwatering problems. Overwatering can affect cannabis in different ways. For starters, it causes the roots to decay.

If you overwater cannabis plants that are yet to reach their growth spurt, the roots begin to rot. Roots play a huge role in holding the plants, facilitating water absorption, and transportation of oxygen and nutrients. Since roots are affected, the small plants die or and if they survive, they become too short.

For indoor plants, the smaller plants are overshadowed by the bigger plants, and they die off. Overwatering commonly happens when you water your plants frequently beyond their needs.

Overwatering your plants is bad because it leads to low yields. It can also cause the plants to die off if you do not address the problem. Giving your marijuana plants too much water also makes healthy ones look unhealthy and make them prone to mold or disease.

When there is excessive watering, nutrient blockage takes place, which affects the plants adversely.

The following factors cause marijuana overwatering;

  • Watering the plants often
  • Giving your plants too much water at a time
  • Poor drainage
  • Failure of leaves to evaporate water
  • Lack of drainage holes on a container

Signs of Over Watering Cannabis

How do you know that your cannabis plants are overwatered? You have to check their reaction when watering them.

signs of overwatered cannabis

The drooping of plants is an indication of root obstruction. If they turn yellow, it’s a sign of persistent overwatering.

Some common signs of overwatering cannabis include:

Brown Edges On The Leaves

Overwatering your cannabis plants can lead to brown spots on the leave’s serrated edges. Some growers find it hard to determine whether the brown spots on the edges result from overwatering or nutrient deficiency.

The burnt spots happen in various parts of the leaves. For nutrient burn, the spots appear at the tips. For overwatering, the spots appear on the edges.

Nutrient Deficiency

Most brown spots resulting from overwatering can be confused with light stress or pH problems. After every watering, the symptoms get worse, and leaves begin to curl.


Another common sign of overwatered marijuana plants is yellowing on the plants, especially on younger plants. Overwatering causes yellowing which is similar to plants undergoing light stress.

Overwatered plants fail to keep up with the growing leaves turning them yellow.

Curling or Cupping

Curling or cupping are symptoms similar to heat stress, where the tip and leaves of the edge curl down or up. If you notice your plant’s leaves are curling down or the bottom yellow leaves are curling up, the plant is suffering from watering issues.

Plants are likely to suffer from overwatering during cold temperatures because they don’t take in much water. You can tell that the brown spots are not due to nutrient burn because they are near the veins compared to the leaf’s tip.

Topsoil Problems

A combination of the above symptoms and the following on your topsoil show your plant is overwatered;

  • Green algae
  • Solid topsoil
  • Fungus gnats
  • Waterlogged soil
  • Divots and indents where you pour water heavily

Mold and mildew

Mold poses a great threat to cannabis. Common molds that affect marijuana include bud rot, fuzzy white mold, and white powdery mildew.

The fungus spreads pretty fast and can affect all your plants. Mold develops in humid environments, which commonly take place from overwatering.

Slowed Growth

Overwatering can cause slow growth or stop plant growth completely. Overwatered plants have trouble growing because they don’t take enough nutrients and oxygen.

Their roots do not function effectively rendering them prone to pathogens that slow their growth.

Pest Infestation

Another sign that should alert you that the plants are overwatered is pest infestation. Root aphids and fungus gnats thrive well in damp environments.

Pests slow plant growth and in severe cases cause total failure.

How to Fix Over Watering Cannabis

The first thing you can do to fix this problem is to allow the growing medium to dry out completely before watering again. Let the plant stay 2-3 days without water.

Other effective ways you can use to fix overwatering include:


If your plants are all grown, overwatering is not that bad if it doesn’t happen daily. If you overwater your plants, let them dry completely. Use enzymes to make the roots grow strong and recuperate from the damages cases by excess water.

Enzymes are an effective catalyst to speed up various processes in your plants for faster growth. They eliminate dead roots in your cannabis plants by turning them into sugar which is then absorbed to provide room for the development of healthy roots.


Another method you can use to fix overwatering issues is choosing the right substrate for your marijuana plants. There’s an array of substrates you can choose from, and they all vary in quality.

Use a substrate that doesn’t hold water longer to prevent overwatering. Substrates with natural peat or perlite are great for marijuana plants. They enable plants to absorb nutrients and water effectively for successful growth.

How to Prevent Over Watering in The Future

You can implement a few tricks to prevent overwatering your marijuana plants. The first step to preventing this problem is to allow the growing medium to dry between watering schedules.

Let the growing medium dry by roughly 60-70% before you water your plants. A soil moisture sensor helps you know the soil’s water content.

overwatering cannabis

Secondly, ensure you don’t have a too compact growing medium. This goes miles to provide ideal drainage for excess water. You can mix your growing medium with clay pellets or perlite.

Thirdly, the bottom part of your growing container should have the right drainage holes to allow the smooth draining of excess water. If the holes in the container are not sufficient, you can always add some by yourself.

Fourthly, when watering, consider your plant’s size, not the container’s. Avoid overwatering your plants thinking they need the excess water. Factors that affect water absorption by the plants include temperature, watering schedule, relative humidity, and root health.

Water your cannabis plants in stages. For instance, if you water one liter of water in a week, about half a liter should be enough the following week. Allow the water to grow media to soak the water until it comes out from the drain holes at the bottom.

Exercise caution when watering smaller plants. Overwatering them can halt their growth.

The following tips should help you water your marijuana plants correctly;

  • Always know the water and nutrient intake of your plants so that you can know when to water them.
  • Before you water your plants, ensure about an inch depth of the growth medium is dry.
  • Lift the growing container to find out the saturation levels before watering.
  • Give your cannabis plants water until you see around 15-20% runoff. This helps to flush by-products in soil and stagnant air. As a result, the removal of unused nutrients rejuvenates the soil.
  • If the medium stays wet for more than 5 days, you need better drainage for your marijuana plants.

Under Watering Cannabis Plants

You don’t necessarily need to water your plants daily. However, the growing medium can get dry, leading to nutrient deficiency, or tired and stressed plants.

Some possible causes of underwatering marijuana plants include:

  • High temperature
  • Infrequent watering
  • Ineffective substrate water retention
  • Anxious beginner grower

Unlike overwatering, underwatering is not common. It takes place when the medium doesn’t have proper water retention. The temperatures can be too high, leading to fast evaporation.

underwatering cannabis plants

When your cannabis plants are under-watered, they appear lifeless, with leaves face down. The root hairs start to dry and become thin. The leaves dry and shrink. Finally, the plant’s aroma reduces.

While plants suffering from underwatering appear lifeless, they take a short time to recover.

How To Fix Underwatering Cannabis Plants:

  1. Provide your plants with strictly the appropriate amount of water. It shouldn’t be less or excess, just sufficient enough for the plant.
  2. Even though underwatering is not as common as overwatering, it can lead to stressed plants. Ensure the substrate doesn’t dry out completely to prevent under-watering.
  3. Always water your plants when the growing medium is damp. Avoid waiting until the leaves are droopy. This is an indication that you’ve allowed the growing medium to stay dry for long.
  4. You should water your marijuana plants after 2-3 days. However, if the soil dries in less than a day, you shouldn’t follow the 2-3-day schedule.
  5. Utilize a soil moisture meter for accurate results on when to water your plants. If the device is not available, use your index finger. If it comes out dry; you should water your plants. If it doesn’t, you can wait for some days.

Final Thoughts On Overwatering and Underwatering Marijuana Plants

Overwatering your marijuana plants can affect the final yield, especially if it occurs often. This is because the plants might not regrow. Additionally, they can suffer from fungi and rot.

However, if you fix this problem on time, you can increase your chances for a better yield. Once you solve the problem, you can proceed with the normal watering schedules.

You need to take care of your schedules to avoid repeating the same mistake. Do not soak the roots when pouring water. Allow the water to go down to the roots instead of pouring it once in the growing container.



About David Rhodes

David has been working in the cannabis industry for the past 17 years with experience working overseas in Amsterdam as a budtender for 5 years! His goal is to help you with your cannabis grow! Learn More About David!

David Rhodes