Watering Your Cannabis: How To Fix Over And Underwatering
Overwatering and under watering your cannabis plants can cause multiple symptoms and may even slow down growth. It’s all about understanding your plants and finding a sweet spot. We explore how to recognize and fix these issues, as well as take a look at the importance of water quality in general.
There are many contributing factors involved when it comes to a successful and bountiful cannabis grow. Lighting, nutrients, airflow, and humidity all play important roles in optimal growth and vibrancy of a crop. Water, however, is one of the most important aspects of keeping cannabis plants healthy and strong.
Watering isn’t always as simple as it may seem. Many growers are under the impression that completely saturating their crop with water each day is all it takes to help plants obtain their aquatic requirements.
The truth is, there is much more to the watering process. Watering cannabis plants is a balancing act that takes some time and experimentation to perfect. Too much water can lead to some serious problems for plants and may obstruct oxygen intake. On the other end of the spectrum, too little water can lead to extremely dry conditions that will leave cannabis plants thirsty, eventually causing them to wilt.
We take a look how to recognise if you are over or under watering, and how to fix it.
OVERWATERING YOUR PLANTS
Overwatering is an easy mistake to make when growing cannabis, and is most likely caused by worrying that plants need constant doses of water. It is a pitfall novice often fall into.
Cannabis plants actually use their root systems to breath air, in addition to uptaking water, and if their roots are constantly swamped in water, they will begin to drown.
1. One primary symptom of overwatering is drooping leaves. However, it is not the same kind of droop you see when underwatered – where leaves look wilted. It is the opposite in fact. Leaves are so full of water, that they are being forced to curl in on themselves. It results in them becoming very firm.
2. Additionally, the rate of growth of overwatered plants will slow down dramatically or may even come to almost a complete halt. This is due to the anaerobic conditions that arise due to the lack of oxygen accessible to the root system.
3. Another symptom of overwatering a cannabis plant is yellowing of the leaves. This is a sign of a nutrient problem, that is a side-effect of overwatering.
If you are experiencing any of these symptoms within your plants and believe the root cause is overwatering, the best thing to do is water less often. Wait for the top layer of soil to look and feel dry before watering again. A good test is to put your index finger in the soil up to the knuckle. if it is dry, consider watering.
Also, make sure each plant has adequate drainage and that water isn’t building up too much in the bottom of the pots or containers that they are housed within. You want excess water to drain out of the containers, leaving soil moist but not waterlogged.
UNDERWATERING YOUR PLANTS
1. Underwatered cannabis plants will look very weak, lifeless, and will show signs of wilting. Its no wonder they begin to look this way considering the vital role of water in plant physiology. The wilting of underwatered cannabis is different from the plump curling of overwatering – even if only subtly. Leaves will be fragile, brittle and even papery. They will look lifeless and drab. Another sign of an under watered cannabis plant an extremely dry growing medium, such as crispy soil.
2. Underwatering occurs when growers simply aren’t meeting their plant’s demands. Without adequate water, the root system will dry up and growth and yield may be reduced. Be sure to water your plant when the top inch of soil has dried out. Leaving it any longer than this may start to have detrimental effects.
3. One aspect that may cause underwatering is not using the correct pot size at certain stages of growth. For example, growing a small seedling in a large pot may reduce the plant’s chances of uptaking enough water, as the small root system doesn’t have a chance to uptake water before it drains away.
WATER QUALITY IS PARAMOUNT
As well as watering frequency, the quality of the water used to supply a cannabis crop is also a highly important consideration.
Cannabis plants consist of approximately 90% water, and the substance is required during various vital physiological process such as photosynthesis and transpiration. When using a poor quality water source to supply cannabis plants, these processes may be less efficient than they can be, or in worst case scenarios, disruptive.
When these disruptions occur, symptoms may manifest that appear almost identical to an array of other conditions such as over or under fertilisation, under-watering, and possibly even heat stress. This is a perfect example of why to always double and triple check the root cause of the problem when troubleshooting health issue of cannabis plants.
HOW OFTEN DO YOU NEED TO WATER YOUR PLANTS?
This question actually has many different answers, as many different variables are at play. For this reason, there is no exact answer. For example, temperature, humidity, and other environmental factors can all change how often water will be required.
However, there are telltale signs that will display it’s time to once again water your plants. Checking the top inch of soil is a promising way to identify this. Wait for this section of the soil to be dry before watering again in order to avoid overwatering. Once you have done so multiple times, you should start to figure out how long it takes in between each watering, and then you can go by that length of time instead.
Paying close attention to your plants leaves is another way to tell if its time to water. Of course, waiting long enough to symptoms to arrive is not optimal, but any signs of wilting should immediately be followed by a dose of water.
Before the growing process, check the quality of your water source. One important factor when it comes to water quality is pH. pH is a numeric scale used to measure the acidity or alkalinity of a solution, with the middle value of 7 representing neutral. Numbers less than 7 represent acidity and numbers above 7 display alkalinity.
PH that is either too high or too low can cause problems in cannabis plants, as the pH of the water source can dictate a plant’s ability to absorb nutrients. Too low or too high pH water can affect the pH of your grow medium over time, which results in symptoms that look identical to those caused by certain nutritional problems.
Cannabis plants tend to thrive at a pH of around 6.5. pH can be measured extremely easily by simply applying a pH metre around a water runoff sample. Runoff is water that drains from your grow container, having passed through your grow medium. If the pH is either too high or too low, pH up and down products can be used to return it to normal levels.
PPM is another important factor when it comes to water quality. Ppm, or parts per million, is a method of measuring the amount of minerals that have dissolved into the water source being used. So, a reading of 90ppm will indicate that there are 90 milligrams per litre of minerals present within the water source.
Being aware of the PPM within water allows growers to avoid giving their plants too many or too little minerals. A lack of minerals may lead to deficiencies, whereas too many may cause burning to occur. Cannabis plants prefer a ppm of around 500 when in the vegetative phase, and favour a ppm of around 1000 during the flowering stage of the grow cycle.
TDS meters, devices that measure total dissolved solids, can be used to measure the ppm of a water source.
Monitoring ppm is quite advanced, and while useful, is not essential for novices finding their feet. Just bear it in mind as you look to expand your knowledge and skill.
REVERSE OSMOSIS WATER
Although the total dissolved solids within your water profile might be adequate, not all substances within a water source are beneficial for your cannabis crop. Water might be contaminated with other factors such as pollutants and bacteria. Reverse osmosis filters are a great option to almost completely remove everything within a water source, allowing growers to add back only what they want their plants to come into contact with.
Reverse osmosis filters are capable of removing between 95-99% of dissolved salts within a water sample and is therefore a standard method of cleaning water on an industrial scale.
Once again, using reverse osmosis water is an advanced growing technique.
With the above in mind, you should be well on your way to understanding how over and underwatering affects your plants – as well as overall water quality in general.
TESTING YOUR WATER RUNOFF
To produce healthy plants, you need to keep a close eye on the amount of nutrients your plants are receiving. To do this, use trays to catch the runoff when you water your plants, and analyse both its pH and PPM (parts per million).
WHAT PH SHOULD YOUR RUNOFF BE?
Cannabis plants tend to thrive at a pH of around 6.5. To check your pH, simply test the runoff using a pH meter. Our pH tester by Hanna Instruments is super simple to use and offers fast and accurate readings. If your pH is either too high or too low, you can use pH regulators to bring it up or down.
Too many fertiliser salts can obstruct nutrient uptake and cause wilting. Use the DiST 4 Pocket Conductivity Tester for accurate readings.
Too many fertiliser salts can obstruct nutrient uptake and cause wilting. Use the DiST 4 Pocket Conductivity Tester for accurate readings.
We explore how to recognise and fix cannabis over and underwatering, as well as the importance of good quality water.
How To Solve Underwatering And Overwatering Of Cannabis
Published : Aug 18, 2019
Categories : Cannabis cultivation
Watering cannabis is a balancing act. Too much and you risk root rot, too little and your plant will dry out. Use these tips to fix any issues with overwatering and underwatering.
The success of a cannabis grow depends on how well the cultivator manages to balance all of the factors required for plant health. Too little nutrients can lead to deficiencies, whereas too much can lead to root burn. A lack of light will result in stunted growth, but if the light source is too close, leaves will wilt and burn. If the humidity is too high, mould is likely to form, and if it’s too low, you’ll end up with dry and unhappy plants. The exact same can be said for watering.
Underwatering or overwatering plants is by far one of the easiest mistakes to make when growing weed. The symptoms of doing either are quite similar in that you’ll notice leaves beginning to droop and a general ill and wilted look to your plants. This guide will explain how to identify signs of both underwatering and overwatering, and how to remedy them.
THE SIGNS OF OVERWATERING
Overwatering cannabis plants is a very common mistake in novice growers. It’s usually the result of caring slightly too much and providing an excess of a key resource. For some growers, the sight of slight dryness in the topsoil is enough to induce panic. It looks as though their plant is about to dry out and die, so they proceed by drenching the soil with too much water, too frequently.
One key piece of cannabis anatomy is the root system. As well as anchoring plants securely into the soil to prevent the wind from blowing them over, the roots act to absorb water and nutrients from the soil below. A little-known fact is that plants also use their roots to take in oxygen. If you give your plants too much water, or the correct amount, but too often, you obstruct their ability to intake oxygen, which then results in symptoms arising.
Common symptoms of overwatering cannabis plants include drooping of the leaves directly after watering and yellowing of leaves if the problem persists.
HOW TO FIX OVERWATERING
The remedy for overwatering is quite a simple one: ease off on the fluids! First thing’s first, leave more time between watering sessions. Probe the topsoil with your index finger and wait until the first 3cm have sufficiently dried out before applying more water. This will generally lead to a routine of watering around every 2–3 days. Additionally, during watering, make sure not to drown your plant each time. Water enough to notice runoff leaving the drainage holes for about 60 seconds after watering, and no longer.
Pot size is also an important factor to consider here. You’ll need to start your seedling off in a small pot and gradually transplant it into bigger pots as it continues to grow in size. If you place a small plant into a big pot too early, the roots won’t be capable of taking in a lot of water from the soil, which means the medium will stay saturated for too long.
THE SIGNS OF UNDERWATERING
Underwatering can occur due to a busy schedule that forces a cultivator to forget, or it can arise in areas of high heat where watering is required more often. Underwatered plants will also appear to have an ill and weak look to them. Their leaves will be dry and droopy, and the tip of the plant may be bent into one direction.
HOW TO FIX UNDERWATERING
It’s possible to get your plant back on track after a period of underwatering, depending on the severity of the situation. If your plant has been significantly neglected and is literally lying on the topsoil, then the chances are low. However, if all you’re seeing is slight drooping of the leaves and general wilting, all it takes is readjusting your watering schedule.
Water your plant until you notice runoff for 60 seconds afterwards. Now, use the same advice as above; wait until the topsoil has dried slightly to avoid swinging to the other end of the spectrum and providing too much water.
WHEN IS THE RIGHT TIME TO WATER CANNABIS?
Even if you know how to manage water-related issues, you still need to establish the best time to water cannabis plants. Timing goes hand in hand with the techniques listed above, varying according to the seedling, vegetative, and flowering stages.
Seedling cannabis plants are particularly vulnerable, especially when it comes to watering—less is more at this crucial stage. Using a spray bottle, rather than a watering can, will help overzealous growers keep hydration under control. Give seedlings a light misting when the surrounding soil has begun to dry and your plants should flourish in no time.
Once a root system has developed, you can switch to watering routines that will see you all the way through to harvest. In line with the guidance above, watering should take place every 2–3 days, or when the surrounding soil is dry to the touch. The most effective way to get into good habits with watering is to water at the start of the day. For outdoor cultivations, plants will have an entire day of sunlight to utilise. If growing indoors, it is helpful to set your grow lights to come on at the start of the day, just as you are watering.
Watering in the evening is an option, but the lower evening and nighttime temperatures can lead to a buildup of mould.
PAY CAREFUL ATTENTION TO PH—IT MATTERS
Consistency in watering routines supports another vital building block of cannabis—nutrition. Your plant’s root system will absorb essential nutrients from its growing medium, but only when pH levels are optimal (6.0–7.0 pH for soil, 5.5–6.5 for hydro/soilless/coco). The key is to keep plants watered on a schedule. Not only does it keep plants routinely hydrated, but it will prevent fluctuations in pH—a symptom diagnosed by brown spots on middle or lower leaves.
To maximise nutrient uptake, aim for 10–20% runoff every time you water. Adopting this approach at an early stage should keep pH fluctuations to a minimum. However, it is especially vital if you are increasing nutrient concentrations for any reason (bloom boosters during flowering, for example).
If you are still noticing problems with your cannabis (deformed leaves, fungus, or spots), it could be the pH of your water that’s the problem. No matter how skilled you are at balancing the pH of soil, water that is too acidic or alkaline can throw all your calculations into disarray. Use a pH tester to make sure you have a level playing field BEFORE you start to use pH-up or down to maintain an ideal window.
Underwatering and overwatering produce similar symptoms and are both detrimental to plants. Learn how to manage watering correctly to avoid these issues.