How To Water Your Marijuana Plants: A Complete Guide

Watering plant when growing marijuana

Knowing how to water your marijuana plants correctly sounds simple, however, striking the right balance is essential to the health and well-being of your plant. Water is one of the many essential parts of photosynthesis. It is a means of transporting and delivering minerals and nutrients from the soil and into the plant. It is crucial to water your weed plants the right amount and at the right time.


How much should you water marijuana plants?

Marijuana plants need a lot of water to thrive and for healthy development. Inadequate water may cause plants to dry up and harm their growth. Contrarily, overwatering can cause nutrient deficiencies and plant diseases. Therefore, it is vital to strike a perfect balance while hydrating them.

Knowing when to water your marijuana plants and how much to give them relies on several different factors:


Stage of growth

The stage of growth your plant is at will make a difference in how much water it will require. Seedlings need much less water. At this stage, the plant is small and delicate so you will also have to be more careful when watering. As they grow bigger cannabis plants require more water, the more sizable the roots grow, the more water they require to grow and stay healthy.



Temperature is another factor to consider. Plants growing outside in warmer climates will naturally require more water than those in cooler areas due to excessive heat. This will also apply to indoor grows where temperatures are higher. It is advisable to keep a thermometer inside your grow area to keep a regular check on the temperature. Using a fan to cool the grow space will help keep things from getting too hot and save you from watering more frequently.


Pot Size

The size of the pot you are using for your plant will make a difference in how often you will need to water your marijuana plant as well. Larger-sized pots will retain water for longer than smaller pots. This also links to the size of your plant at the time as well. If you have a young plant in a big pot then it is not good to completely soak the growing substrate, as it can drown the poor young plant before it’s grown. This also applies the other way around. Large plants with extensive root growth in a small pot will absorb the water you give it in a very short time. This is a reason why many growers transplant their cannabis plants into bigger pots the more the plant grows.

Another factor when considering the container you’re using when watering will be the type of pot you use. You always need a pot that allows excess water to drain out. However growing in containers such as air pots will mean you reduce the risk of overwatering your plant, however, it will mean you have to water it more often.


Growing Medium

The type of growing medium you use largely determines how much water the soil can hold, and drainage plays a big role in how often and how much you will need to water your plants. Cannabis likes rich, yet airy types of soils that are well-draining. More compact soil mixes will hold moisture much longer, so they require less frequent watering. Otherwise, moisture can linger in the soil for some time, which can lead to nutrient deficiencies, root rot, fungus, pests, and a whole lot of other problems.

If you find the soil you are using is retaining water for too long, you can add perlite or something similar to your soil to aerate the mix and improve its drainage ability. Perlite ensures that water doesn’t stay too long in your pot. The key to good soil for cannabis plants, whether store-bought or homemade, is to balance moisture retention with water drainage.


Health of the Plant

Plants affected with diseases or having sluggish growth would need less water, compared to healthy ones.


How to check if your marijuana plants need watering

Knowing when your plants need watering can be determined by a few simple measures. One of the most common ways to check is to insert your finger about 5cm deep into the soil. If it contains moisture, then avoid watering the plants. But if it feels dry, then it’s time to water them.


Another way to check if your cannabis plant needs watering is to lift the pot to determine its weight. If it feels heavy, then avoid watering. Alternatively, if it feels light, then the growing medium has dried up and requires watering.


To get an idea of how a pot containing water feels like in your hands – when they are dry or damp. Do this experiment with the help of a dummy pot.


How do you know if your plant is underwatered or overwatered?

Limp and drooping leaves

When cannabis plants need watering the signs are usually quite obvious. If you see the plant looking generally unhealthy, with the leaves drooping down, it usually means that the plant is thirsty. However, it is worth noting that if a plant has been overwatered it will look similar. If you are struggling to tell the difference, a simple way to check is to feel the surface of the soil, if it is bone dry to the touch then it will most likely be underwatered.


The look of the leaves will also give you an indication as to whether the plant is overwatered or underwatered. Generally, the drooping leaves of an underwatered plant will be droopy and look drier. Whereas an overwatered plant’s leaves will appear darker in color and look heavier.


Yellowing leaves

Another sign that your plants have been underwatered, is if the leaves are discolored or beginning to turn brown or yellow. It is normal for the leaves of a plant to turn yellow during the end of the flowering stage, however, if this begins to happen earlier, it could be an indication of underwatering.


It is normally always easier to fix the symptoms of an underwatered plant rather than an overwatered one. So always be mindful of how often you are watering your cannabis plant.


How do you water your marijuana plants correctly?

It is necessary to provide the correct amount of water to prevent various problems in the future. The frequency and the quantity of water needed may constantly vary depending upon the changing weather and environmental conditions.

About 25-33% of the pot volume would be sufficient and ensure proper hydration for the plants. It will help in preventing fungus/pests and bacteria in the plants.


Water pH level

The pH level of the water you use plays a vital role when watering your marijuana plants.

A pH range of 6.0 to 6.7 is optimum if cannabis plants are grown in soil, and 5.6 to 6.5 if grown without soil. pH levels outside this range will mean the plant cannot take in nutrients, even if they are present, therefore causing nutrient deficiencies.


Collect water runoff

It is an easy and effective way to avoid supplying excessive water to cannabis plants. It is necessary to take corrective action immediately after seeing the signs of underwatering or overwatering cannabis.


Use a tray to collect the excess water from the pot. Make sure that the runoff water has passed through the growing medium and drains from the pot.

If the soil feels dry, ensure that the plants are receiving adequate nutrients and water.


Watering your plants when you’re away

You may have to depart from your plants for several reasons.

The following are a few effective methods to maintain the health of the plants in such cases:


Ask a friend for help

Ask a trustworthy and experienced friend to properly feed, maintain and oversee the plant’s health regularly. Explain to them the watering schedules to be followed. It is the cheapest and most convenient method.


Homemade DIY drip system

This method will ensure a constant supply of water to the cannabis plants while you are away.

To make your own DIY drip system follow these simple steps:

  • Take a plastic water bottle and drill holes in the cap.

  • Fill the bottle with water.

  • Cover the bottle tightly with the cap.

  • Dig a hole in the soil contained in the pot.

  • Place the bottle upside down into the hole.


High-tech and long-term options

These methods require investment in terms of money and technology. It ensures the proper hydration of the plants for a longer time.


Irrigation systems - slow drip system with timer

Management tools like remote sensors detect and monitor moisture levels, collect data, and ensure that all the plants are perfectly watered. Growers control the watering schedules through their devices such as timers and wifi.

The timer turns on, drips the water into the pot for a specified time, and turns off. Install the timer on the faucet and select the start and endpoints. The timer controls the irrigation system by sprinkling water in the plants. It is easy to apply this technique and it automates the watering schedule.

Slow drip system
Slow drip system

Watering your marijuana plants is such an important factor in producing a healthy, productive plant that it’s key to getting it right. The principles are easy and just take care and consideration.


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