distilled water for cannabis

Best Water for Growing Plants | Cannabis

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Water is one of the most important things when it comes to life as we know it on our planet, including plants, but what is the best water for growing plants? It stands to reason that the quality of the water that you give your cannabis plants directly influences the quality of the final result. People generally tend to use the first water that they can get their hands on, which is usually tap water – combined with the fact that people usually add loads of different products to the water in order to feed their plants without checking pH or EC, this can be disastrous. Your plants will be more likely to catch plant illnesses and attract insect and fungi infestations, which can lead to terribly quality flowers once harvested.

In order to guarantee quality flowers and to make the most out of the nutrients used, the most important thing is to make sure that you know the type of water you’re going to use, and its contents. Secondly, you’ll need to work using specific pH and EC levels so that your plants can absorb everything they need; these levels vary depending on the phase your plants are in and depending on the strain grown. This is why you absolutely need pH and EC meters when growing cannabis, although this post is more about different types of water and how they can be used.

What’s the Best Water for Growing Plants?

We’re going to go through a few different types of water that you can use when growing plants, whether they’re cannabis, flowers, aromatic or decorative plants – many people have misconceptions regarding this issue.

Tap Water

Tap water is probably one of the most used types of water when it comes to watering cannabis, as it’s definitely the easiest to access. Whether you should use this type of water or not depends on where you live, as the water in certain areas has different characteristics than others. You should be able to check this at the town hall or through town officials Tap water can be hard, (EC + 0.8), medium (EC + 0.4) or soft (EC – 0.4), and it generally has a pH of over 7.0 as well as containing a lot of products that help keep it clear. Tap water also contains lime, chlorine and fluoride in some cases, which can kill natural life in soil and decrease its quality.

In order to water your plants using tap water you can do various things; let the water sit for about 24h so that some of the minerals and other components have time to fall to the end of your tank. The second thing that you can to is you can use an osmosis filter in order to clean your water and make it potable for both people and plants.

Distilled Water

Distilled water is sold in supermarkets and drug stores, and it doesn’t contain any minerals or any other type of microorganism, bad or good. This water is perfect for plants and can be consumed by people although due to the fact that it contains no minerals at all it’s not recommended for continuous consumption. In order to use it on plants, all you have to do is keep in mind that it generally has a pH over 7.0 and an EC of 0.0, so we recommend adjusting the pH and adding calcium and magnesium until it reaches 0.4 EC.

Distilled water is obtained through a process of distillation, which essentially heats the liquid up until it becomes vapor. The vapor is then cooled down in order to retrieve the water, with every other component having evaporated.

Air Conditioner Water

Air conditioner water is taken from your very own air conditioner, and you can use this water when it comes to watering your cannabis plants, as it’s essentially distilled water, although we always recommend using an EC meter; depending on how old the AC unit is or its design, it may actually have an EC of 0.4 rather than 0.0. Its pH is usually over 7.0.

Reverse Osmosis Water

Reverse osmosis is a type of water that’s similar to distilled but not quite as pure, as it doesn’t eliminate 100% of all minerals (lime, chlorine etc.) and other impurities in water, but it’s incredibly similar and you can get it from your own type by simply getting a decent osmosis filter and setting it up. Depending on the filter and how long it’s been there for, osmosis filters tend to produce less than 0.4 EC and around 7.0 PH, so you can drink it if you want and you can use it to water your plants without needing to modify it at all.

Reverse Osmosis water is obtained by using filters that trap the minerals and other unwanted elements in the water; depending on the filter and the model, the water will be more or less pure, and therefore higher or lower quality. Reverse osmosis water is always a better bet than tap water or water that you can get from rivers/lakes etc.

Rain Water

Rain water, as the name suggests, is water obtained straight from nature herself, filling tanks up with rain which you can store and then use at a later date. This water is generally not potable, although some studies would suggest that it is. Regardless, it can be used to water pretty much any type of plant, as when rain is gathering it tends to automatically eliminate any harmful elements, plus plants in nature grow using rain water; rain water is one of the cleanest fresh waters on earth. It tends to have a pH close to 7.0 and an EC no higher than 0.4.

In order to get the highest quality rain water possible you’ll need to set up a water collection system, which will need to stay as clean as possible in order to avoid absorbing elements that could decrease the quality of the water. You can also have it set up on an impurity filter. We recommend using rain water obtained outside of cities, as the rain that falls in the city is usually contaminated as it falls through an already contaminated environment.

Well, reservoir, spring water etc.

Water obtained from wells, springs, reservoirs and other similar sources is not entirely recommended unless you actually know its composition via a study done in your area; you need to know its mineral and chemical content. This is absolutely necessary, as it may have been contaminated using chemical insecticides or mineral fertilizer, which might render it useless for your plants. Plus, these types of waters tend to contain large amounts of bacteria, fungi, virus and parasites due to animals and possibly even people.

In order to use this type of water we highly recommend studying it beforehand and then, if necessary, treating the water or preparing your storage area to avoid bacteria from spreading. If it’s a well that you own, you can empty and treat the surface using ultraviolet light, or you can also treat it with chlorine. If it’s a spring or reservoir or somewhere public, you’ll need to talk to the authorities in the area in order to figure out its contents and take the necessary measures if the water isn’t apt for plants or life in the area.

River Water

River water may sound like a great idea for watering your plants at first, and maybe even for drinking, although this is not recommended at all. Rivers are generally kilometers long and can have stretches in which they’re contaminated by pesticides, industrial areas or factories that use the water for residues; rivers can also contain dead animals which contaminate water due to decomposition.

On the other hand, the location of the river can give its water unique characteristics; you’ll never find the same type of water in two different rivers. Plus, due to the content of certain minerals, it’s probably more than likely not apt for cannabis growing and you’ll need to analyze all of its contents, not just pH and EC.

In order to use river water you should probably live near somewhere where your town hall can assure you that the rivers don’t contain any sort of contamination caused by human kind. If you nonly have access to water that’s in rivers near or in cities, we highly recommend avoiding using it.

Bottled Mineral Water

Bottled water is obviously designed for people to drink, although it’s not the best option for cannabis plants. Still, it’s better than using unknown tap, river, or well water. Mineral water is guaranteed to contain no harmful substances, and its EC levels are lower than 0.5, with a pH around 7-0, although it may have high amounts of different minerals which may end up affecting how your plant grows and how the soil behaves, such as calcium.

In order to work using bottled mineral water you need to choose a brand that has the lowest amount of minerals, and you need to adjust the pH and EC like you would with any other type of water; it’s easy.

The Best Water for Growing Plants

So, after going through various different types of water you can use when growing cannabis, including some you may not have thought of, the best water for growing plants is clearly reverse osmosis or distilled water. These two types of water can guarantee that your plants aren’t getting any toxic minerals or anything they shouldn’t get unless you’re adding it to the water – it also makes it easy to give your plants a 100% controlled diet. Let’s have a look at our ranking of the type of water you should use for growing your cannabis plants:

  • Distilled water
  • Reverse osmosis water
  • AC Unit water
  • Bottled mineral water
  • Rain water
  • River water
  • Well, reservoir etc. water
  • Tap water

This ranking is of course just an estimate, and the different types of water mentioned in this post may vary in position depending on their individual characteristics related to location and environment.

Do you want to know what the best water for growing plants is? Read on to find out how to get the most out of your crop through correct water prep!

Water – How to Water Marijuana

Watering marijuana plants properly is essential to any grow. Knowing how to water marijuana and how often you need to be watering marijuana plays a big part on the final buds produced. With a little bit of knowledge on a few things before you start, like what water actually does, what your water should and shouldn’t contain and how frequently you should be watering marijuana plants, you’ll be growing healthy buds in no time and will avoid learning the hard way.

Why do you water your marijuana?
Your plant uses water as a medium to transport the necessary nutrients it needs to live. If you use poor quality water which contains lots of impurities, these will be transported into your plant. Generally, if your water is good enough to drink, then it is good enough to use on your plants, but not always!

What are acceptable pH levels?
You want the water you’re using to have a pH as close to neutral (pH 7) as possible as the medium and nutrients you use will affect the pH levels. Marijuana feeds between a pH of 5.8 and 6.8, which are the levels at which the nutrients are at the most effective. Outside of these levels, the nutrients can “lock out”, which means your plant is unable to use them and starts to starve. To make sure your plant can still feed on the nutrients, keep a close eye on the pH levels of both the water and medium. You’ll find it’s easier and more accurate if you buy a digital pH meter. If you’re struggling to get your pH to where it should be there are products called pH Up or pH Down, which can be used to bring your pH levels in line and can safely be used alongside any nutrients.

Grow Tip: Always check the pH levels of your water/ nutrient solution and medium before watering your marijuana. This might seem like a waste of time, but if you have any problems, it’s good to be able to rule out the pH level before looking for more difficult issues to solve.

Grow tip: Tap water changes throughout the year as the seasons change, so keep an eye on the pH before adding any nutrients you may be using.

What’s the best water to use when watering marijuana?

Can I use tap water?
The simple answer is yes, provided it has a reasonably neutral pH and the correct levels of parts per million (ppm). Water with more than 140 ppm of total dissolved solids isn’t suitable for use on your marijuana grow as it will interfere with any nutrients you’re using, causing them to lock out or toxify your plant. If this is the case, we recommend finding another water source, i.e bottled water. Whether you live in a hard or soft water area will affect any changes you may need to make as hard water can contain too much calcium and lock out other nutrients. Soft water may require you to add a little calcium (CalMag), especially if your medium or nutrient mix doesn’t contain it.

Distilled water
Some growers hold the belief that using distilled water speeds up your marijuana plants growth. Whether or not this is true is another matter, but if you’re growing in a hard water area, you may want to consider using distilled water because hard tap water may cause your plants problems as it contains elements that could stop your plant from feeding on other nutrients. An effective way to purify your water is to bring it to the boil and then let it cool. You can use bottled water from your local supermarket, making sure the bottle is R.O or distilled, otherwise do not use it! Try to avoid using water that has been carbon filtered as it will not remove the impurities and metals found in tap water. If you’re serious about using distilled water, the best way to deal with impurities is by using a Reverse-Osmosis machine, which will remove all dissolved solids from your water! It might seem extreme however if you intend to grow on a bigger scale it’s a worthwhile investment.

Grow tip: Chlorine is not bad for your plants and is essential to help process oxygen in photosynthesis. Most manufacturers of nutrients take the amount of chlorine in tap water into account when making their mixes. Bear this in mind when watering marijuana plants with distilled or R.O water.

How to water marijuana – How much water do I need?

The size of your marijuana plant, the medium you’re using, and the size of the container all have an effect on the volume required when watering marijuana plants. A general rule of thumb is to water every other day, but there is a simple way of telling when you should or shouldn’t. Before watering marijuana plants, tip them to one side, or even pick it up to measure its weight, then water your plant as you would normally and repeat the process. This enables you to measure the weight it should be and when it needs water. Your plant will tell you if you are giving it too much or too little water (see below) and it won’t take long to learn when your plants are in need of some H2O.

Grow Tip: The smaller the container, the more frequently you will need to water the plant.

Grow tip: When watering marijuana plants for the first time, make sure the water is draining out of the bottom of the container. Allow to soak through and water again after 30 mins as this will enable the moisture to spread throughout the whole medium evenly.

Grow tip: Make sure the medium you are using has good drainage as this will significantly decrease your chances of over watering marijuana plants. Perlite can be added to your growing medium to increase drainage.

Over watering and under watering your marijuana plants – What to look for.
For the beginner marijuana growers, over and under watering are the most common mistakes. As plants grow, so does their need for water and nutrients. As you get used to telling how much water is needed, your plant(s) will give some tell tale signs if it is receiving too much or too little.

Over Watering Marijuana
Problems it causes?
Over watering your plant drowns the roots by cutting off the supply of oxygen, causing slow growth and increasing the possibility of fungal attacks. It’s normally the result of poor drainage, and can be avoided by making sure your medium holds a decent amount of oxygen or adding perlite to increase drainage.

What to look out for?
Stunted growth of your plant.
Leaves start to curl down and yellow, but are stiff.
Soil is soggy.

Under Watering Marijuana
Problems it causes?
Under watering plants is common and can cause roots to die off as they dry out, resulting in slow growth and wilting plants. It’s more common in smaller containers where a plant needs more frequent watering as it grows. Pockets of dry soil can also be a cause of under watering so make sure the moisture in your medium is spread evenly by double watering your plant whenever it goes into a new container.

What to look out for?
Stunted growth of your plant.
Leaves will start to curl down and yellow, but will be limp.
Soil is dry to touch.

A basic guide to watering marijuana plants.

Use the following as a basic guide to watering your marijuana plants:

Your water should be around room temperature, ideally 70°F (21°C). If you’re using water out of the cold tap, allow it to sit and become room temperature before you pour around the base of your plants, otherwise it will put them into shock. AVOID HOT TAP WATER as this contains more impurities.

Water at the start of your light cycle as this will give your plant a chance to use it straight away, promoting good growth. It will also help avoid any potential for the water to sit and drowned the plants.

Pour water around the base and not over the top of the plants. If you want to prevent pests through using water, lightly mist your plants at the start of the day when you are watering. Do NOT MIST your plants once they are FLOWERING as this encourages mold to grow on the buds.

Take pains to avoid getting any water on your light bulbs as this may cause them to explode.

Over watering marijuana plants is a common mistake made by many novice and experienced growers. Knowing how to water marijuana is fundamental if you are going to successfully grow big plump buds.

26 comments on Water – How to Water Marijuana

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Too much or too little water is a common problem; ensure your plants stay hydrated with our watering guide and you’re sure to grow blossoming buds.