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How To Water Cannabis Plants: A Comprehensive Guide

Your cannabis plants need water in order to thrive. Seems simple enough, doesn’t it? But did you know that incorrect watering is the most common reason for plant health issues? Learn how and when to water your plants so you can avoid any problems before they have a chance to happen!

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Watering cannabis plants seems like the easiest thing to do, yet many growers, especially those new to cannabis cultivation, make mistakes with watering. Overwatering is one of the most common reasons for all sorts of growing troubles such as nutrient deficiencies and cannabis diseases, although giving your plants too little water can also negatively affect their growth.

HOW MUCH SHOULD YOU WATER CANNABIS?

One issue with watering plants is that it isn’t really an exact science, and many different factors contribute to how much you should administer. As an obvious example, as your plants get bigger, their watering needs will change. But there are other, more complex variables that also determine how much or little you should drench your plants. Let’s discuss some of the most vital:

STAGE OF GROWTH

Cannabis plants have different watering demands depending on their stage of maturity. The specific guidelines we share below apply to mature vegetating and flowering plants. Seedlings and clones require much less water.

In the early stages, avoid watering your plants with a powerful stream that might knock them over and disturb developing roots. Instead, use a light mister to gently moisten the substrate.

Wait for the soil to dry out completely before repeating the procedure. How quickly the soil will dry will depend on your environmental conditions, but this roughly translates to misting once every 2–3 days.

GROWING MEDIUM

The type of growing medium you use largely determines how much water the soil can hold, and drainage plays a huge role in how often/how much you water your plants. Cannabis likes rich yet airy and “fluffy” types of soils that are well-draining. As another consideration, the growing containers themselves must have holes punctured in the bottom to allow the water to escape. More compact soil mixes will hold moisture much longer, so they require less frequent watering as a result. Otherwise, moisture can linger in the soil for some time, which can lead to nutrient deficiencies, root rot and fungus, pests, and a whole lot of other problems.

Here is a quick way to check if your water is draining properly: If it takes several minutes for water to drain after drenching the soil, and/or if it takes longer than 3–4 days for your soil to dry out, it’s likely that you have a drainage issue. Even if you don’t see adverse symptoms now, it could definitely lead to more problems down the line. In this case, you can add perlite or something similar to your soil to aerate the mix and improve its drainage ability. Perlite ensures that water doesn’t stay too long in your pot. The key to good soil for cannabis plants, whether store-bought or homemade, is to balance moisture retention with water drainage. This usually means soil that is dark and rich, but amended with perlite and/or other substances to promote a healthy and efficient medium for plants to grow.

SIZE OF CONTAINER

Then of course, the dimensions of your container will also affect the overall balance between moisture retention and drainage. If you have a tiny plant in a huge pot, drenching the whole substrate is going to drown the poor thing before it gets a chance to flourish. Similarly, you might experience the opposite issue with huge root-bound plants stuck in minuscule pots. This is also the reason that growers normally start seedlings in smaller pots, then up-pot them later as the plant grows. A small seedling pot makes it much easier not to overwater the sensitive seedling.

OUTSIDE TEMPS AND LIGHT INTENSITY

Cannabis plants don’t always grow at the same pace. A plant in a cooler environment, for example, will grow much slower than one under balmier conditions. Light intensity plays another big role here. Plants that receive more heat and light are bound to have higher water and nutrient requirements than those with meagre light and chilly temps.

HEALTH OF CANNABIS PLANTS

The general health and vitality of your plants will also determine how much water they require. If growth is slow or stunted, or if a plant is afflicted with diseases or pests, it will likely not need as much water as one that is thriving.

HOW TO TELL IF YOUR PLANTS ARE THIRSTY

You now know about the factors that determine how much and how often cannabis plants need water, and how these factors can be different for everyone. So now, how can you tell exactly when you should water?

Here are some signs that your cannabis plants are thirsty:

DROOPING, WEAK PLANTS

If your cannabis plants are very thirsty, they will droop. The whole plant will appear rather sickly and lifeless, so it’s difficult to overlook this sign. One catch here though is that thirsty plants can look very similar to those that are drooping because of overwatering. The difference here is that the leaves of overwatered plants are usually dark green and form a “claw” where they curl and bend downwards, so the whole plant takes on a heavy and waterlogged appearance.

If you’re somewhat experienced, you should be able to tell these conditions apart. Most of the time, it should be obvious if the drooping is from over or under-watering: If the soil is bone-dry and you know you haven’t watered in quite some time, the sickly appearance of your plants is less likely from overwatering.

Tip: Know that slightly underwatering your plants is always better than overwatering. If you water thirsty, otherwise healthy plants, they should normally recover their appearance in a couple of hours. Occasional underwatering doesn’t usually have harmful consequences. Overwatering, on the other hand, is a silent killer.

YELLOW OR BROWN LEAVES

Along with your thirsty plant wilting and drooping due to a lack of water, it may also display discoloured leaves in shades of yellow and brown. While it is perfectly normal for plants to develop yellow leaves during the final weeks of bloom, a healthy vegetating plant shouldn’t have any/many dry, yellow, or brown foliage.

JUST CHECK THE SOIL!

Take the guesswork out of your watering routine with a simple method. Placing the tip of your finger into the top 5cm of soil provides a good indicator of how dry the upper soil has become. However, it won’t allow you to detect the water content of the middle and bottom of the growing medium.

Weighing your pots instead will give you a clear picture of how much water remains. You can operate based on a general feeling of how your containers feel in your hands when they are dry compared to when they are saturated. Even better, weigh them to know exactly when they’re ready for some more H₂O.

HOW TO WATER YOUR CANNABIS PLANTS

Here is a simple rule: Water less, but water well! Rather than giving your plants a little bit of water often, treat them to a healthy, less frequent soak. But how much water is sufficient?

A good soak means watering the medium to 25–33% of the pot capacity. This amount of water will provide the root system with all it needs, without causing pooling and potential fungal issues.

When watering, aim for the middle of the substrate first. After letting the roots breathe, water the edges of the container too. This approach will encourage the root ball to reach to the edges of the pot, and also shuttle nutrients sitting in the top of the medium down to the root system below.

This method will deliver the correct amount of water, without creating pools in the substrate. Excess water creates a humid environment—a perfect breeding ground for fungal pathogens that lead to root rot.

DON’T LEAVE YOUR PLANTS SITTING IN RUNOFF

Along with your containers featuring holes at the bottom for water to escape from, the containers themselves should be lifted slightly off the ground so that all the water can drain and plants aren’t sitting in stale liquid. Drainage trays can catch this runoff, but should immediately be dumped after collection to avoid creating a breeding ground for bacteria, pests, and mould.

THE IMPORTANCE OF PH WHEN WATERING PLANTS

If you are growing cannabis organically in soil, you shouldn’t need to worry much about the pH level of your water/nutrient solution. But for the majority of cannabis growers who are using common mineral nutrients and grow weed in soil, coco, or hydroponically, the correct pH level of the water is very important.

The reason for this is that cannabis plants have a limited pH window where they are able to take in nutrients. If the pH level of the water is either too high or too low, the plants are unable to take in nutrients even if they are present, a phenomenon known as nutrient lockout.

When you grow in soil, the pH range of your water should be 6.3–6.8. If you grow soilless (e.g. coco) or hydroponically, the pH level needs to be even lower, 5.5–6.1. To test your water pH, use a pH measuring stick or pH measuring drops. If the pH is too high or too low, use some drops of “pH down” or “pH up” to adjust your water to the right level. Most of the time, if you’re using tap water, your pH will likely be too high.

Also, if you’re adding cannabis nutrients to your water, measure the pH after each feed. This will give you accurate data of how you have influenced the soil. It will also let you know if you need to add more nutes, or modify the dose during next feed.

BOTTOM LINE—WATER WELL, BUT NOT TOO OFTEN!

If you know how and when to water your plants, and are aware of any associated issues along the way, you can prevent most common cannabis growing problems. You will raise happy, healthy plants, and can look forward to fantastic yields!

The HI-98107 pHep pH tester provides fast and accurate pH readings. The easy-to-use device is designed for non-technical users, and can help both novice and advanced growers measure water pH.

HI-98107 pHep pH tester provides fast and accurate pH readings. The easy-to-use device is designed for non-technical users, and can help both novice and advanced growers measure water pH.

Click here to find out everything you need to know about how and when to water cannabis plants. Watering may seem easy, but many growers still get it wrong.

How Often Should I Water My Cannabis Plants?

If you are new to growing Cannabis indoors or outdoors, having a thorough understanding of how frequently you should be watering or how often your plants require it can be quite difficult. There are many factors that play a huge role from the cultivar, the maturity of the plant, grow room temperatures and humidity, the growing substrate integrity to drain as well as retain nutrient solution, the chosen growth cycle and much more. Below we’ll explain what you should know when it comes to watering your Cannabis plants.

1. The Best Way To Water Plants

There is no set way to water Cannabis plants or any type of house plant for that matter, however, each grower has their own set way, based on what is most practical for them.

Top Feeding Small Amounts Frequently: This is the most basic way to water plants without oversaturating them. Normally a grower will add enough water until the growing medium has become moist. By watering in this instance, the growing medium will always stay well saturated, yet will never be encouraged to dry out and increase air capacity.

Watering Until Runoff: This method is the same as top feeding, however with the intention of pouring in enough water or nutrient solution, and waiting around 30-60 seconds for a slow release of water to emerge from the bottom of your plastic or felt pots. One of the benefits of watering this way is oxygen is pulled through the entire grow medium as water escapes and air displacement occurs.

Bottom Feeding Only: A very simple and foolproof way to water your plants by allowing the roots to suck the water up. This only happens correctly when the growing medium is dry enough, to cause a wicking action that will draw the water upwards to the roots. Many growers swear feeding in this manner is the most advantageous, then again many will debate that the buildup of salts is far greater.

Hydroponic Applications: Regarded as the commercial scale farming model, watering using timed irrigation not only saves physical labor but also ensures the plants are fed the exact same amount, on a consistent basis. Organic growing mediums fed with drip stakes will grow much faster than when hand watering, and is replicated on enormous scales in the agricultural sector.

When growing Cannabis organically, using drip stakes will help your plants to grow much quicker. This is commonly replicated in commercial scale farming of vegetables and is also the most efficient way to water a large scale crop.

2. Plain Water or Nutrient Solution?

Hydrating a plant is one thing, however, feeding a nutrient solution is different and there are a few things to consider. The root hairs of a Cannabis plant only need to come into contact with a fine film of water to be able to tap in and extract what they need.

Feeding Plain Water Only

This is basically as organic and simple as one can be, as Mother Nature does all the rest. As all of the necessary primary and trace elements can be found in abundance inside an organic living soil, all that is required is to keep the moisture levels adequate for the living microorganisms. Compost also depends on specific temperatures and moisture levels in order for organic matter to break down over time.

Using Nutrient Solution

Most growers who follow a nutrient feeding chart will feed a mix of different nutrients until the final few weeks. During the last part of the flowering cycle is the flushing period where plain water is fed to the plants for two reasons.

Break Down Undissolved Salts

The build-up of nutrient salts that can develop over a 10 week period or more can be quite excessive. Especially if using chemical-based nutrients that are designed for hydroponic systems. Water is the source of life and is also a solvent in its own way, meaning the final 14 days will help wash away the remaining salts increasing the flavor and quality of the ash.

Using Up The Reserve Nutrients

Even though it may seem a drastic change to switch from a maximum nutrient solution, it is necessary to starve the plant forcing it to use up all of the reserved nutrients. This is when Cannabis plants will begin to exhibit rapid deficiencies and is a sign the nutrients are being used up.

3. Over Saturating The Grow Medium

There is nothing worse than having the best intention, but unfortunately over watering your plants. In the event your growing medium is inadequate regarding drainage and wicking capacity, then the drying process can be very slow causing many issues to occur.

– Transpiration that occurs through the leaves will need to compensate for the excessive amount of water around the roots. As plants find a way of transporting water through foliage or the root zone, by over saturating you are jeopardizing the integrity of the plant’s growth, causing stunted growth.

– Wilting of the fan leaves is a clear indication you have over-saturated your root zone, and the plants are not happy. Even though underwatering shows the same trait, do not feed more water and allow your growing medium to air out until the pot is light to pick up.

– A cold and wet root zone will cause anaerobic bacteria to infect your garden and kill your plants. It is extremely important to keep your root zone oxygen-rich and one reason why felt pots are so popular.

– Cannabis plants will fail to uptake certain much-needed nutrients if the water levels are too great. The results will be a lockout in nutrients and line of deficiencies to begin occurring one after another.

4. Top Tips When Watering Your Plants

– An excellent way to calculate the watering ratio is to feel the weight of your growing medium when it is at the lightest with no water. This is the point your plants need to be each time before watering. By doing this you will always know when to water without running the risk of oversaturating.

– Always use a set measurement of water so the plants receive a consistent amount every time. The easiest way to do this is to use a 1 to 5 litre bottle and accurately fill the same amount.

– If you are hand watering from the top and are not sure if the medium is wet enough, simply insert your entire finger down the side of the pot. Judge how moist or dry your finger feels and this should give you a clear indication of when next to feed.

– Using irrigation and pump to water your organic Cannabis plants is wonderful and will help you to take that back-breaking work out of the garden, allowing you to replicate commercial scale farming concepts.

– It is better to water plants with room temperature water than cold, as cold water can cause shock and encourage a cold root zone.

– Avoid watering late at night close to lights out, as the plants will not get a chance to use it until lights are on. Humidity levels in the garden can increase and oxygen levels and temperatures around the roots will drop.

5. 3 Best Recommended Heavy Feeders

For all the growers who like to give their ladies the best nutrients on the market, we have picked our 3 biggest feeders to keep you company in the grow room.

If you are new to growing Cannabis indoors or outdoors, having a thorough understanding of how frequently you should be watering or how often your plants requir