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.
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.