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Growing Indoors

How Often Should Indoor Plants Be Watered?

How Often Should Indoor Plants Be Watered

Water is among the most vital necessities that must be provided to cannabis plants in the right amount to make it flourish. However, as mundane as the task might seem, several factors that must be considered such as its quality, frequency, and pH level.

Failure to adequately provide hydration to plants can result in stunted growth, vulnerability to diseases, mold infestation and other pathogens, and in worst case scenarios – death.

The Essentials Of Watering Indoor Plants

Indoor cultivation entails more attention concerning watering schedules and amounts. In the absence of rain or other natural phenomena that could serve as a water source, indoor plants solely rely on the water provided by cultivators.

Cannabis Water System

Water Quality

Cannabis plants require specific water requirements for it to thrive. This is because unsuitable or poor water quality can negatively impact various physiological processes such as transpiration and photosynthesis. When this happens, the plants will manifest signs such as wilting and drooping. Ultimately, leads to sickly plants with fewer yields. In extreme cases, it could hinder the absorption of nutrients resulting in an irreversible catastrophe.

To prevent such problems from occurring, the Potential of Hydrogen (pH) levels and parts per million (PPM) of the water to be used should be monitored.

pH level. This is the numerical scale used for measuring the acidity and alkalinity of water. The pH level has a significant impact on how the plants absorb nutrients. As such, tilting too much towards the alkaline or acidic ends of the spectrum causes problems in nutrient uptake. For this reason, the water must be kept within the ideal pH range of 6.0 to 6.8 where plants could best absorb the different minerals it needs for growth.

It is also noteworthy that the growing medium has its pH levels, too. Hence, when monitoring, pH meters should be used on the run-off water. If it is observed to be too acidic, dissolving garden lime can increase pH levels. On the contrary, if the water is too alkaline, adding white vinegar will reduce the pH levels.

PPM. Parts per million is a measurement that determines the volume of nutrient minerals present in the water. It could be measured and monitored with the aid of TDS meters. Too much of these minerals can cause burning, while the lack thereof will lead to deficiencies. Hence, ensuring the appropriate ppm prevents excess or deficit provision of minerals.

In the case of cannabis plants, the appropriate levels depend on the current growth phase. Plants in the vegetative phase flourish at 500ppm whereas 1000ppm is ideal during the flowering stage.

However, not all minerals and other dissolved solids in the water are advantageous to cannabis plants. Harmful bacteria and pollutants may contaminate water, and those can only be prevented through the use of filters such as reverse osmosis filters which can remove 95% to 99% of dissolved salts and bacteria in the water.

Amount And Frequency Of Watering

It is not enough to provide suitable water for the plants to make it flourish. The amount and frequency of watering should also be monitored. This is because plants in different aspects of growth have different water requirements. Moreover, several other important factors must not be overlooked. Otherwise, improper watering practices can cause problems such as wilting, drooping, and root rot among others.

1. Stage Of Growth

Cannabis Seed Sprout

Cannabis plants in different stages of growth require different amounts of water. However, it is difficult to accurately state how much because this will depend on other aspects such as the growing medium, pot size, and environmental factors.

  • Seedlings. Naturally, seedlings would need fewer amounts and less frequent watering because it has not yet developed an elaborate network of roots.
  • Vegetative stage. During this phase, the plants will need just enough water for some of it to flow out of the pot drainage. At this stage, it needs all the water and nutrients it could get to have sufficient energy to grow. Plants could also absorb moisture from the leaves. Spraying directly on the leaves help keep the moisture in plants but also lessens the growth of more roots. Hence, it should be limited to once or twice per week so as not to cause adverse consequences.
  • Flowering stage. During the flowering stage, the need for water decreases. The watering amount and frequency must be reduced progressively because too much of it can attract molds in the buds. Moreover, the plants must also be watered without fertilizers during the last 3 to 4 weeks before harvest.

2. Geographical Location

In warmer climates, plants need to watered more often because the heat causes moisture in plants to evaporate and transpire at a faster rate. Usually, the soil dries out in just one day or less.

Plants in colder locations need to have different watering frequencies adjusted depending on the season. Watering frequency is fewer, though, due to a wetter environment and soil could take longer than three days to dry.

3. Size Of The Plant And Container

New Grown Marijuana On Bucket

Generally, large plants must be planted in large containers. This, in turn, need more water for it to seep all the way through to the bottom. Providing insufficient amounts can lead to wilting. Conversely, young and minuscule plants must be nurtured in small pots. With fewer amounts of soil, less water is needed. Too much and it gets stagnant and attracts insects and fungus that causes root rot.

As a rule of thumb, seedlings are planted in small, 1×1” starting pots and given small amounts of water. Once its root system develops more extensively and outgrows its container, the plant is then transplanted to bigger pots. This is also an excellent opportunity to see if the plants have healthy roots. White, thick, and well-developed roots are indications that the plants have been watered well.

There is also an option to plant the seedlings directly into a larger container to circumvent the hassle of transplantation. If this method is preferred, then even if a big pot is used, it would still require less watering as the seedlings cannot take in much water in its current state. Only when the plant has developed roots should more water be gradually provided.

4. Room Temperature

Geographical location affects the temperature of the grow room. Growing indoors, though, has one significant benefit over the outdoors – the virtually endless options for customization meant to not only control the environment but to optimize it further.

One routine but essential task is closely monitoring the temperature as well as the humidity. These are variables affected by equipment such as grow lamps and ventilation fans. Even the stage of growth would require a certain level to be maintained.

5. Growing Medium

Cannabis Sprout On Soil

Different growing mediums have varying ways of absorbing and retaining water. For this reason, each media also needs different watering amount and frequency.

  • Soil. In this traditional medium, the best way to determine if it needs watering again is by poking a finger 1 to 2 inches deep from the topsoil. If it feels dry, then it is time to water it again. Otherwise, it is not necessary. And, when watering, it is important to keep watering until some water has leaked out of the bottom hole to ensure it is adequate and well-distributed.
  • Coco coir. This medium has excellent water retention, but its watering requirement is similar to soil. Generally, it has to be watered every 1 to 2 days. Do not wait for it to dry out before watering again but do not sprinkle water yet if its top inch still feels wet. If the coco coir stays hydrated for more than 3 days, then that means that it received too much water previously and the amount should be lessened in the next watering schedule.
  • Rockwool. This medium has dense and porous fibers that allow for some breathing space and high water absorption. Additionally, Rockwool also provides excellent drainage. Its watering frequency is lesser compared to soil because of high water absorption and retention level.
  • Perlite. This pH neutral medium can trap water and slow down evaporation. It require less frequent watering due to high water retention properties.
  • Vermiculite. Generally, vermiculite is a light medium that has excellent water retention. Hence, it is often mixed with other mediums. It holds water as a sponge would, until the soil begins to dry. Vermiculite, when used alone, requires less frequent watering.
  • Clay pellets. This pebble-like media has high water retention. Clay pellets, because of its porous surface, drain water quickly thus requiring more volume of water but less watering frequency.

6. Humidity

The amount of moisture in the air mostly depends on the temperature and ventilation of the cultivation area. In an enclosed space, and most especially with plants profusely stretching outwards, humidity level could fall out of the optimal range due to lack of air circulation. Grow lamps such as HPS could be emitting excessive heat and affect the moisture too.

Sitting in humid environments prompt the plants to decrease transpiration or water evaporation through the leaves. Therefore, less frequent watering is needed. It is vital to determine the moisture level to prevent overwatering.

Drainage System

It is crucial for pots to have holes at the bottom. This serves as the drainage system that allows run-off water to flow outside the container – thereby preventing stagnant water from teeming inside it. When water accumulates, the roots get submerged and consequently drowns due to lack of oxygen. This could also put plants at the mercy of pathogens and diseases such as root rot.

To ensure that a pot or container has a proper drainage system, observe how long the water drains out. If it takes more than a few minutes for the water to leak out, then the medium itself may be holding off too much water. It is recommended to mix dense mediums with lighter ones, such as perlite, to loosen the soil.

Additionally, a drainage system is also useful for saving water. The excess water that comes out of the drain can be collected for future use. This is especially useful during dry weather, or when there is a water shortage.

Flood-and-Drain System

In the case of water shortage, it is recommended to use a flood-and-drain system for cannabis plants. This is useful for stimulating the plants to grow faster and healthier. Moreover, it is an easy way to have a consistent watering schedule across all the plants in a large growing area.

Healthy Roots Of Marijuana

The flood-and-drain system involves placing potted plants in a tub that is attached to a reservoir. When it is time to water the plants, a water pump is turned on until the entire tub is “flooded,” letting the plants absorb water through the drain holes. After a few minutes, the water is then “drained” back to the reservoir.

However, this system is only limited to plants with roots that have reached the bottom of the container. Also, the water needs to be replaced every week to prevent bacteria and pollutants from building up.

Watering Problems And How To Fix It

Seeing how vital water is to plant’s survival, a deficiency or excess come with unpleasant consequences. Remedying, though, is easy.


Excessive watering inhibits plant growth. Some problems that result are drooping and root rot. However, the signs are easily observed thus corrective measures can be promptly applied.

  • Drooping. The abundance of water and lack of oxygen commonly observed in overwatered plants causes drooping. This is because overwatering can force plants to store more water in its leaves in an attempt to get rid of the excess water drowning the roots. This, in turn, causes the leaves to curl down and droop. Unlike wilting leaves, drooping leaves will look very firm with some discoloration. It appears limp because the leaves are holding the weight of too much water. This condition negatively impacts the growth of the plant by stunting it.
  • Root rot. This plant disease occurs when the roots of the cannabis are deprived of oxygen, as well as when there is not enough oxygen dissolved in the water. This will cause the plants to grow slower, lose strength, and become prone to pathogens – hence, causing the root to rot.

The Solution

When the symptoms of overwatering occur, it is best to water less often. The key is to wait for the soil or medium to feel dry before watering it again.

Furthermore, provide the plants with a proper drainage system to ensure that no water accumulates at the bottom of the pots. Drainage helps expel excess water and leave the soil with a healthy moist.

In case of root rot, adding a few tablespoons of hydrogen peroxide into the water helps by killing bacteria and provide oxygen to the roots – thereby solving two problems at once.


This problem occurs when the plants are supplied with scarce water. It could also be caused by using a large pot for growing small pots or an environment that is too hot. Either way, it causes wilting and significantly slows down the plant’s growth. Upon receiving insufficient water, the leaves will appear shriveled and weak. It could lead to death if not resolved immediately.

The Solution

Such predicaments can be easily remedied simply by providing adequate water. However, it may be difficult – if not impossible – to revive severely damaged plants that have been underwatered for a long time.

Use water with a pH of 6.0 to 6.8 helps in rehydrating and recovery. Moreover, water could be sprayed in the leaves to revitalize it. Once the plant seems to have regained strength, use fertilizers to help restore the nutrients that were lost.

Maximize Yields With Proper Watering Practices

One of the goals of cannabis cultivation is reaping prolific yields. Thus, the plants must be nurtured and carefully grown with the right amounts of the vital elements it needs – one of which is water.

High Potency Cannabis

Watering practices can make or break a plant’s growth. Poor watering practices lead to weak roots, sickly leaves, smaller buds, and ultimately, lesser yields with dismal quality. As such, gaining knowledge on these proper watering practices is a must for maximizing the growth.

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