What water should I water my marijuana plants with?

Variants of water sources that can be used for germination and watering of cannabis plants.

cannabis plant after watering

Whatever water source you decide to use for your marijuana plants, the first step should be to test the water. Let the water sit and measure the pH, especially after adding fertilizers. In case of poor pH, nutrient uptake is impaired or even stopped.

Optimal water quality for cannabis plants

In hydroponic cultivation, we give the marijuana plants water with a pH of 5.5-6.5 and 6-6.8 in the soil. The pH we choose should be maintained. Keeping the pH of the water within an acceptable range allows the roots to absorb more nutrients. The water temperature for marijuana plants should be between 20-22 degrees C.

Description of water sources


Rainwater is usually the best for cannabis plants. It is natural and can be obtained for free in reservoirs. However, due to human pollution, rainwater may not be ‘perfectly clean and pH neutral’.

Spring water:

This is essentially groundwater, which varies from one area to another. Test this water before use and treat it if necessary before feeding it to the cannabis plants.

Tap water:

One of the most affordable sources of water for any marijuana grower. Chlorine is usually added to water to treat it against bacteria and contaminants. Chlorine will naturally evaporate from water when left outside for 24 hours, but if your water was treated with chloramine or fluoride instead of chlorine, you would already need to use a filter to treat your water for such removal.

Bottled water:

It can be a good source if the amount of minerals is within the required range and does not contain harmful chemicals. However, watering cannabis plants in this way is expensive. Most cannabis growers who are not 100% sure of the quality of their water source use bottled water for germination and the beginning of the growing phase.

Distilled water:

This water contains no nutrients whatsoever, so you have to mix all the additives into it , which is ideal because you have control over what you add to it. This is important because distilled water sucks out all the good nutrients that your marijuana plants need to thrive. Distilled water is ideal for hydroponic growing, but is not suitable for watering the soil with pure water.

Osmotic water

The water is purified by a filtration process called reverse osmosis. This process also removes dissolved solids, viruses and bacteria from the water down to one millionth of a metre in size, so that it can be said to be almost perfectly pure water. The same applies to osmotic water as to distilled water.

If you are interested in tips on how to water correctly, take a look at our article.

Published by Peca Sarm


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