1. Tap Water
The number one question in the context of choosing the right type of water for watering marijuana is “Can I use tap water?”. This question is popular because tap water is the obvious and most affordable option for most growers. Moreover, people who grow large amounts of cannabis seek to save on water.
Firstly, tap water may differ: both soft and hard or medium-hard, as it depends on the specific city or area where you live (information about this should be public). It is considered that tap water can not be used for irrigation, as it often has a high content of chlorine, fluoride, and lime, which destroy microorganisms, including those beneficial to the plant. This makes the mineral content too high for normal cannabis growth. To get rid of excess chlorine, you need to leave the water to stand for 24 hours or more. The minerals contained in the water will settle and remain at the bottom, after which the plants can be watered. The second method is osmosis filters, which make water drinkable for humans and plants faster.
If you follow these rules and do not water the plants immediately, tap water may be suitable for watering your cannabis.
2. Distilled Water
Distilled water is water that is devoid of any minerals and microorganisms. It is sold almost anywhere and does not require additional filtration. By choosing distilled water, you will be sure that it is completely clean and filtered. Despite this, such water is also devoid of necessary and useful minerals, so it can not be watered plants directly. To make distilled water suitable for watering cannabis, you have to adjust the level of ppm: add calcium and magnesium. Ordinary distilled water can absorb nutrients from the soil, so they will not penetrate in adequate quantities into the plant.
Rainwater is a great option for watering cannabis. Rainwater is used naturally to water plants growing outdoors. Besides, rainwater is considered to be one of the purest freshwaters with an ideal pH and ppm level. However, there are some disadvantages compared to other types of water. First, you will have to set up your rainwater collection system and minimize its interaction with the environment so as not to contaminate with foreign substances, which is a labor-intensive process. It is also recommended to collect rainwater outside the city, where it is usually dirtier. Second, rainwater should be checked, as its purity cannot be taken for granted.
Thus, despite the affordability and relative purity of rainwater, its use requires additional work and verification of water quality indicators.
4. Reverse Osmosis Water
This type of water is very often used among cannabis growers, as this method is very reliable and simple. All you need is to purchase a RO filtration system that retains most of the minerals and harmful substances contained in the water. However, such a filter cannot filter out chlorine and some solvents, so some growers use other filters in addition to RO filtration. The downside is that you need to purchase a suitable filtration system. Also, the degree of purification and, accordingly, the quality of water depends on the characteristics and price of a particular filter.
5. Bottled Mineral Water
Bottled water is hardly considered as an option, as it is not economically viable for growers. This type of water is purified with a medium pH level, but the bottles may contain too many minerals depending on the brand of water and its characteristics. Excessive minerals, as we already know, negatively affect the growth of cannabis.
6. River Water
River water is considered unsuitable for drinking and watering plants. This is because river water can contain pesticides, industrial waste, the remains of dead and living animals, and various minerals. All this together creates the most unfavorable qualities for watering cannabis. To use such water, it should be unambiguously tested for harmful substances, especially water from urban rivers. River water is unique to each section of the river, so be careful before watering marijuana with river water even if you tested some part of the river.