Crops need love too! Cannabis plants thrive when provided with the right amount of water and nutrients. Learn everything you need to know about watering your cannabis plants. No more guessing or worrying! How much water your plants need, how often you should water, and what influences a cannabis plant´s water absorption rate.
How to water a cannabis plant
Cannabis is generally a resilient plant, and most strains can tolerate mistakes with feeding and watering to some extent. However, consistently delivering water and nutrients in the wrong concentrations or quantities can cause deep-rooted problems that can prove detrimental—or even fatal—to your crop.
Cannabis plants need abundant water, particularly in the flowering stage. As a general rule, plants should never be deprived of water for too long at any stage of their life cycle, as this can severely slow or even halt growth entirely. As well as this, depriving plants of water deprives them of nutrients, which not only slows growth but can lead to deficiencies.
Moderation is key
However, over-watering is a mistake many new growers make. Over-watering can lead to pythium (root rot), botrytis (grey mould) and powdery mildew, as well as causing nutrient toxicity and anaerobic (oxygenless) soil conditions in extreme cases. These issues can be disastrous, and are often extremely difficult for newbies to correct.
Most growers agree that soil should be allowed to dry out slightly between feeds—this lessens the risk of rot, mould and nutrient burn, and may also encourage the roots to grow denser. However, plants should always be watered before the roots start to dry out.
Finding the right balance is crucial, and it varies according to the strain (tropical sativas may be remarkably thirsty, while many indica strains abhor damp) and the size and growth stage of the plant—as well as other factors such as choice of medium.
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When should cannabis plants be watered?
There is some controversy over the best time of day to water cannabis plants. Most growers believe that cannabis should be watered at night time, but some argue that they should be watered earlier in the day.
Those that believe cannabis plants should be watered at night argue that in a natural environment, precipitation does not fall when the sun is shining, due to cloud cover. Many also state that if water droplets resting on the leaves are exposed to heat and bright light, they may act as “magnifying glasses” and burn the leaves.
It appears that this is just a myth, although leaf burn can occur through prolonged contact with some fertilisers. In any case, possible issues can be avoided altogether if care is taken to simply direct the water towards the soil and not the leaves!
On the other hand, watering earlier in the daytime allows the plant to utilise the available nutrients more effectively, as many of the fundamental processes of plant growth occur in sunlight. Leaving soil damp throughout the cooler hours of night can promote mould growth.
If growing outdoors, watering in the morning rather than the warmer afternoon appears to be optimal, as the rate of evaporation is slower. If growing indoors, watering at around the time lights are switched on may be preferable—while temperatures rise quickly with “hot” lights such as HPS, it usually takes some time for them to peak.
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How often should cannabis plants be watered?
At first, young plants will require small amounts of water at frequent intervals—up to twice per day if room temperatures are high and relative humidity is low. As they mature, they may be fed less frequently with greater quantities. Typically, large flowering plants must be fed at least once every 2-3 days.
The correct time to water plants should become apparent upon testing the moisture level of the growing medium. It should feel dry on top, but still somewhat damp below the surface. If it remains dry to the touch at depths of more than 5cm or so, plants are probably too dry.
This may all vary widely according to the drainage properties of the medium. For example, coco typically requires daily watering at first, then twice-daily as the plants increase in size; this is due to the fact that it retains water extremely well, so giving too much at once can saturate the medium and reduce airflow.
With experience, a visual check or simply testing the weight of the container will aid in determining when to feed, as a dry container obviously weighs substantially less than one full of water.
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A step-by-step guide to watering cannabis plants
First, prepare your equipment. You will need a source of water, a pH meter, pH down (this could be any strong acid), your chosen nutrients, and a watering can, hose or similar.
Water should be around room temperature—hot or cold water can shock and stress plants severely and sometimes irreparably. Most agree that water should be left to stand for 24 hours before use as this allows pH to be more accurately determined.
pH should be between 6.0-6.5 if growing in soil; if growing in soilless medium this value may be somewhat lower (coco prefers the 5.5-6.0 range). Use pH down to reduce pH if necessary, making sure to mix well. Incorrect pH can result in nutrient burn and various deficiencies, as roots are unable to process nutrients as effectively.
Add nutrients according to the manufacturer’s instructions, and mix thoroughly. Nutrient concentrations may be adjusted according to the strain and the stage of growth of the plant—such as when plants are young, or just after being transplanted.
Using a watering can, hose or similar, water the plants until runoff is visible in the trays beneath the pots. Many growers aim for around 10-20% of total water draining off, as this is believed to prevent nutrient build-up—but this is disputed.
Nutrient build-up occurs due to oversupply of nutrients (or reduced uptake by the roots due to overwatering or pH issues), and is fixable by flushing with pure water and not by adding more nutrient solution.
This basic guide should give novice growers all they need to successfully water and feed cannabis plants. However, adjustments to the basic principles may need to be made according to local climate, choice of strain, type of medium, and several other factors.
Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
How Often Do I Water Indoor Marijuana Plants?
If you’re growing marijuana in soil or another growing medium like coco coir, you will have to hand-water your plants. Watering is an important part of growing cannabis indoors, and knowing how to water your plants will save you a lot of frustration!
How often do you give your cannabis water?
Well, you will want to water your marijuana whenever the top of the soil or growing medium starts to feel dry. I like to water when the medium feel dry up to my first knuckle, or about an inch.
- Soil – Water plants when the soil feels dry up to your first knuckle (or if the pot feels light).
- Coco Coir – Aim to water plants every 1-2 days. If coco is staying wet for 3+ days, try giving less water at a time until plants get bigger and start drinking more. Don’t wait for your coco coir to dry out, but don’t water if the top inch feels “wet”. If the container feels light, it’s definitely time to water!
How to water cannabis properly (when using a well-draining potting mixture with liquid nutrients)…
In soil, wait until the topsoil feels dry about an inch deep (up to your first knuckle – just use your finger to poke a hole in the soil and see if it feels dry).
In coco coir, you want to water every 1-2 days if possible and adjust the amount of water you give accordingly. The top inch doesn’t need to completely dry out between waterings.
If you’re regularly adding nutrients in the water, give enough water each time that you get 10-20% extra runoff water drain out the bottom of your pot. This prevents a buildup in the potting mixture because otherwise, you are continuously adding more nutrients to the system.
Go back to step 1. Note: If water takes a long time to come out the bottom, or if pots take longer than 5 days to dry out before the next watering, you may actually have a problem with drainage (more info below) or need to give less water at a time. If your plants are very small compared to the container they’re in, give water more sparingly until plants get bigger.
Growing in Super Soil?
- If you’re growing in super soil or another heavily amended potting mix, you may not need to add extra nutrients to the water because your plants can get all their nutrients directly from the soil.
- Any time you’re not adding extra nutrients in the water, you want to avoid getting runoff water because it will carry away some of the nutrients in the soil.
- Watering until you get runoff is important when using liquid nutrients because it helps prevent nutrient build up, but with super soil try to give just enough water that you wet the entire medium but don’t get extra water coming out the bottom.
Some growers swear by the “lift the pot” method to decide when to water your plants (basically wait until your pot feels “light” since the plants have used up all the water). It’s up to you to decide what’s easier for you.
I usually water my cannabis with a 1-gallon water jug for small grows, or 5-gallon jugs for larger ones. Runoff water is collected in the trays and after a few minutes I suck it all up with a small wet vac .
How to Provide the Water
When I first started growing, I gave my plants water using a watering can. A watering can works great, but it’s hard to water a bunch of plants with one watering can because you have to keep filling it up.
An old-fashioned watering can will get the job done, but they typically don’t hold a lot of water at a time, which is inconvenient if you’re growing a lot of plants
I personally like using a Battery Operated Liquid Transfer Pump to water the plants. You can pump water from a bigger container to your plants. This is a 3-gallon water container from Wal-Mart, and the pump just reaches the bottom.
My grow tent is 2 feet deep and this reaches the plants in the back. However, I don’t think the tube is long enough to reach the back if your space is deeper than that.
Some growers set up elaborate drip feeds to pump water if they have a lot of plants they can’t easily reach, both homemade or pre-made.
Let us know if there’s something we missed. Growers get creative!
How to Collect Runoff Water
It’s important to keep plants on saucers or trays so you can remove the runoff water. You can collect the saucers one by one and dump them out, but that also gets inconvenient with many plants.
It’s inconvenient to empty saucers one by one if you have a bunch of plants, but you don’t want to leave plants sitting in runoff water
If you put your plant on plastic trays, and then put the trays on a slight incline by putting something small underneath in the back, it will catch all the runoff water and cause it to drain to the front. The item in the back only needs to be about half an inch thick, for example a piece of plywood. However, if you can find something more water-resistant, like plastic, that’s even better.
These 1’x2′ plastic plant trays work well if they fit your space. You can fit four of them in a 2’x4′ grow tent (this is the grow tent I use) with up to two plants each as long as your plant containers are 11″ wide or smaller at the base.
Put trays on a slight incline by placing something underneath the tray in the back. This causes all the water to come to the front for easier collection. Each of these trays has a small plastic board (which we found around the house from something else) under the back. Anything that’s about half an inch high will do the trick. These particular trays accommodate plant containers up to 11″ wide at the base.
Not sure how to remove runoff water after watering your marijuana? Wet vacuums can be a great choice, especially if you already have one in the house. I didn’t have one, so I got Bucket Head attachment which can turn any standard 5-gallon bucket into a wet vac. You can buy one online but it’s $10-15 cheaper if you get it in person at a Home Depot. Another similar option is the Power Lid, though it’s also a bit pricey.
A downside to the Bucket Head is it’s a little loud, just like most wet vacs. Luckily you only need to use it for a few minutes after watering your plants!
Removing runoff water is a great start to make sure you are watering your cannabis plants perfectly, but it’s also important to…
Make Sure Pots Have Good Drainage
It’s very important to make sure that water can drain freely from the bottom of the pot, otherwise, the plant can get waterlogged and become overwatered (causing the plant to droop).
In addition to making sure the actual container has drainage (holes on the bottom, or some other way for extra water to escape), it’s also important to make sure your growing medium drains freely. If it takes several minutes for the water to come out the bottom of your pot when you water, it means that there isn’t enough drainage in the actual growing medium (it’s too dense, so water is having a hard time getting through).
How to improve the drainage of your growing medium
- Never use dirt you find outside. Chances are it does not have the correct properties for vigorous cannabis growth.
- Mix in extra perlite to loosen the soil and allow water to drain through more easily.
- Bark or wood chips are not the best choice for growing cannabis plants, even though they’re sometimes recommended to improve drainage in soil for some types of plants. On that note, avoid using soil that contains bark or wood chips. What makes soil good or bad for growing cannabis?
- Use Smart pots – these fabric pots help get oxygen to your roots (which gives you faster growth) and this type of pot makes it harder to overwater your plants. A cannabis plant growing in a tan fabric smart pot is pictured to the right.
This is an example of great soil for growing for cannabis – rich, composted, and well-draining
Composted super soil lets you grow organic marijuana without any extra fertilizers or nutrients
Watering Too Often? Barely at All?
In the beginning of your grow, you will likely be watering your marijuana plants every couple of days. Watering every 2-3 days is optimal for a young plant. If it’s taking too long for your plant to dry out, you may need to give less water at a time until the plant is growing faster.
If you feel like you are watering your plants too often, you may need to give more water at a time. You can also move plants into a bigger pot (which holds water for longer).
If plants take longer than 3-4 days to dry, make sure your potting mixture has good drainage and consider giving less water at a time
If plants are drying out in 1 day or less, try giving more water at a time or transplanting to a bigger pot
Speaking of pot size, it is generally best to start young cannabis plants in relatively small containers (like a solo cup with a few holes cut out of the bottom for drainage), and move plants into bigger containers as they get bigger. Starting in smaller containers makes it a lot harder to overwater your plants when they’re young, and makes it easier to flush plants and/or respond to problems if they occur.
That being said, you can plant your seeds right into their final container. Just be careful not to overwater your seedlings at first if they’re in a big container as they’re not drinking much water in the beginning.
If you started your plants in a solo cup, I’d recommend moving to a bigger pot once the plant is a week or two old, as soon as the leaves reach the edges of the solo cup.
10-20% Extra Runoff Every Time You Water (if you’re providing nutrients in the water)
Every time you water your plants, make sure that you provide enough water to get about 10-20% extra run-off out the bottom of the container, especially if you’re feeding additional nutrients in the water.
Sometimes soil and soilless growing mediums like coco coir start to collect natural salts from fertilizers that never get washed out.
These built-up salts can eventually cause nutrient problems, pH problems, and nutrient lock-out if they’re not removed on a regular basis.
Making sure you keep adding water until you get run-off is also a great way to make sure that your plants are draining properly.
Plus, this practice will immediately alert you to any drainage problems, (as mentioned earlier, cannabis likes well-draining soil) because you’ll be able to notice if the water takes a long time to come out the bottom, or doesn’t come out at all.
Different Nutrients for Different Stages of Life
First, make sure you’re using proper cannabis nutrients for your growing medium. They should be formulated for a plant like tomatoes, and they should have a different feeding schedule for the Vegetative (Grow) and Flowering (Bloom) stage.
If using nutrients on a regular basis by adding them to your water, it’s generally a good idea to give your cannabis plants nutrients every watering. This ensures the amount of nutrients in the plant root zone is kept relatively stable. If you notice the tips of leaves getting burnt from nutrient burn, it may mean you need to lower your overall strength of nutrients. Most nutrient recommendations on the side of the bottle are too strong for cannabis plants, and should be cut in half unless plants appear pale or lime green (which means they want higher levels of nutrients overall).
If Growing in Composted or Amended Soil, Give Just Enough Water That the Soil is Wet All the Way Through
When growing in composted and amended soil, the soil itself is made to slowly provide nutrients to your plant throughout its life. However, if you’re regularly watering until you get a significant amount of runoff, you’ll also be washing away some of your nutrients.
This is good when the plant is getting the nutrients directly in the water, to avoid unwanted buildup in the soil, but try to avoid a lot of extra runoff if you want your nutrients in the container to last until harvest.
Therefore, when growing in amended soil you should only water until you get just a drop or two of water runoff out the bottom. You want to ensure you gave enough water to reach the bottom of the pot without letting a significant amount of water run out the bottom.
Proper watering practices will greatly help reduce the amount of salt buildup and prevent nutrition problems from occurring.
If your cannabis plants shows signs of drooping, often the plant is getting too much or too little water, but not always. Drooping can be caused by….
- Too much water at a time, or giving water too often
- Not enough water at a time, or giving water too infrequently
- Drooping can also occur in hot conditions, or when it’s very humid or dry because the plant isn’t able to move water properly through the plant.
- Plants sometimes get droopy if they are given a lot of water after being allowed to dry out for too long, due to the stress of the water pressure quickly changing at the roots.
- Drooping is almost always associated with something going on at the roots, but plants also tend to put their leaves down a bit right before the lights go off, as if they’re preparing to “sleep” for the night. That can sometimes be mistaken as drooping when its actually part of the plant’s natural rhythm.
In order to prevent over or under-watering, make sure you water thoroughly every time (don’t just water a tiny spot in the middle of the pot unless you plant is very small for the container). You should be getting 10-20% extra runoff water every time if you’re adding nutrients in the water. In soil, wait to water again until the top inch of the growing medium feels dry, up to your first knuckle or so. In coco coir, aim to water the plants every 1-3 days if possible, and don’t let the top completely dry out between waterings.
Underwatered Marijuana Plants
- Wilting is the first sign of underwaterd marijuana plants
- Leaves are limp and lifeless, they may seem dry or even “crispy”
- Will eventually lead to plant death if not corrected
Overwatered Marijuana Plants
- Drooping / Curling is the first sign of overwaterd marijuana plants
- Leaves are firm and curled down all the way from the stem to the leaf
- Will eventually lead to leaf yellowing and other signs of nutrient problems if not corrected
If your plant is experiencing “the claw” and not just normal drooping (like the ends of leaves are just pointing down like talons, then you may actually have a nitrogen toxicity (too much nitrogen).
Nitrogen Toxicity (“The Claw,” tips bent down, dark leaves)
Learn more about Nitrogen Toxicity
How Often Should I Water My Cannabis Plants?
Knowing the right time to feed your plants can depend on many variables, so find out more below about what to consider in order to maintain the perfect watering ratio.
- 1. Factors that influence cannabis watering
- 1. a. Medium
- 1. b. Pot size
- 1. c. Pot type
- 1. d. Environmental conditions
- 2. The best way to water cannabis plants
- 2. a. Soil and coco
- 2. b. Hydroponics
- 3. Plain water or nutrient solution?
- 3. a. Feeding plain water only
- 3. b. Nutrient solution
- 4. Oversaturating the cannabis grow medium
- 4. a. Overwatering
- 4. b. Overfeeding
- 5. Top tips for marijuana watering
- 6. Best recommended heavy feeders
- 7. Cannabis crop watering faq
- 8. In conclusion
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 such as the pot size, strain, conditions, and substrate. In general, you should water when the medium is around 60-70% dry.
Below we’ll explain what you should know when it comes to watering your Cannabis plants.
1. Factors That Influence Cannabis Watering
First of all, every grower needs to understand that a question like “how often should I water?” is basically pointless because your watering schedule will depend on your own specific growing environment. There is no set way to water Cannabis plants or the best time to feed 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.
There are multiple elements that can dictate how much water or how often you need to water your cannabis such as genetics, the phase your plant is in, growing setup and if you’re feeding with every watering or not, but the main ones are pot size, medium, and the environmental conditions.
As you may know, the substrate is where the roots will be growing, and depending on your preferred mix, it can hold more or less water which can affect the amount of water you need to water with and how long it takes for the water to evaporate. For example, if your substrate contains more perlite, it will allow more oxygenation which can increase the evaporation rate, or if it contains a lot of coco fiber it can take longer for the water to evaporate due to coco being able to retain water for longer.
Another factor that can affect how often you water your cannabis plants is the pot size because if there’s more substrate you will have to water with more water and it will take longer for the water to evaporate, obviously, this depends on the stage your plant is in. If your plant is still a seedling you don’t want to water it with a lot of water even if it’s in a 60L pot, but as it grows, you will have to water more and it will take longer for the water to evaporate (when compared to a 10L pot) depending on the conditions.
The type of pot you use, and the conditions inside the pot will have an effect on how often you will need to water your cannabis plants. There is a huge range of options available, but they are definitely not all equal. No matter what type of pot you end up using, drainage should be high on your list of concerns. Many novice cultivators fall into thinking that over drainage is a bad thing, as the plants won’t have a chance to feed properly from the water before it all drains away. This could not be further from the truth. To have the healthiest and most vigorous growth possible, you want your pots to offer high levels of drainage.
If you are using everyday plastic pots you will probably want to drill a few extra drainage holes before you start planting. It’s also a good idea to add a layer of pebbles at the bottom of the pot to help with overall drainage down the line. This stops the drainage holes from becoming clogged and ineffective. Here at FatsBuds, we recommend using air pots or smart pots, especially if you are going to be growing your weed indoors. These pots are made from canvas or fabric and allow for air exchange directly through the material which offers far better root zone oxygenation than terracotta or plastic pots.
This promotes the healthiest and widest-reaching root growth possible and allows for easier root zone temp control. These types of pots do tend to dry out a little quicker than traditional options, so keep that in mind when watering and make the necessary adjustments.
But the main factor that influences how often to water is the growing conditions. This happens because, if the humidity levels are too high it will take longer for the water to evaporate whereas if the humidity is too low, water will evaporate faster.
Also, if the humidity is too high it will encourage the transpiration process, making plants absorb more water and evaporating it faster while a lower temperature slows down transpiration and will take longer for the water to evaporate.
2. The Best Way To Water Cannabis Plants
As said above, there’s no better way to water plants, this will depend on your setup. There are several ways to water plants, either by hand-watering, having a drip irrigation system, and bottom feeding among others.
Soil and coco
Soil and coco (with any other things mixed in such as perlite and etc.) are the most common mediums and allows you to water any way you prefer.
This is the most basic way to water a weed plant. Normally you will add enough water until you see runoff. By watering weed in this instance, the growing medium will always stay well saturated, yet will never be encouraged to dry out and increase air capacity.
A very simple and foolproof way to water your cannabis 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. It can also lead to mold and root rot issues if the system is not maintained to a high standard, so always be careful to drain the remaining feed water between feeds.
Drip irrigation system
A drip irrigation system is not very common amongst soil growers but it can be a great choice for coco or hydro growers. This method consists of a small hose on top of the pot that waters your cannabis plants by releasing drops of water non-stop. So to help you have an idea of how much to water and how often, here’s a small guide to help you water your cannabis properly.
Cannabis watering schedule for beginners
|Coco or Soil||≈100-200ml||≈300-600ml||≈700-1500ml||Usual amount of water + 10-20%||Every 2-4 days|
Just have in mind that this guideline was designed for plants grown in 10-12L pots and under optimal conditions, which are:
- Seedling stage – 65-70% humidity and 20-25°C
- Vegetative stage – 70-40% humidity and 20-26°C
- Early Flowering – 40-50% humidity (lowering approx. 5% each week) and 22-28°C
- Late Flowering – 30-40% humidity and 18-24°C
Your plant’s metabolism is affected by the conditions and will determine how much water your plant absorbs.
Just have in mind that even if your growing the same strain, it all comes down to your plant’s metabolism wich is affected by the conditions, so for example, if you’re growing our Wedding Cheesecake Auto under 30°C in 45% humidity, your plant will need much more water than the same strain under 25°C in 60% humidity.
Now, when growing hydroponically you need to have a drip irrigation system or any other system that waters your plants automatically. Watering using timed irrigation not only saves physical labor but also ensures the cannabis 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.
Cannabis watering guide for aero and hydroponic setups
|Hydro (Perlite, clay pellets, or rockwool)||100-400ppm||500-1200ppm||100-1600ppm||As close to 0ppm as possible||15min ON, 15min OFF (24/7)|
|Aeroponics||100-400ppm||500-1200ppm||100-1600ppm||As close to 0ppm as possible||5s on 4-5min off (24/7)|
So, to help you avoid overfeeding and give you an idea of how much you should feed your cannabis, here’s a table for hydro and aeroponics. Have in mind that the amount needed for soil or coco will differ depending on the brand you’re using so you should follow what they recommend.
When growing in hydro or aeroponics, it’s better to feed your cannabis by measuring the parts per million (which is basically the amount of nutrients in the water in a 1/1000000 concentration) in your nutrient solution.
Measuring ppm instead of measuring by ml/L it’s better because you get a more exact amount of nutrients, water contains a small amount of micronutrients (aka trace minerals) and due to your cannabis being directly exposed to the water, they will end up absorbing it. So when growing in either of these methods, we highly recommend measuring the pH and measuring the ppm of not only your nutrient solution, but also of the water source; Remember that water purity is very important when growing in hydro or aeroponics.
3. 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.
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 (aka flushing) 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.
4. Oversaturating The Cannabis Grow Medium
There is nothing worse than having the best intention, but unfortunately, too much water or nutrients does not result in more growth, so overwatering or overfeeding your cannabis will have a toll on your plants.
In the event your growing medium is inadequate regarding drainage and water-retaining capacity, then the water evaporation 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 oversaturating you are jeopardizing the integrity of the plant’s growth, causing stunted growth.
Also, wilting of the fan leaves is a clear indication you have over-saturated your root zone, and the plants are not happy.
This can also happen when underwatering, which is when your plant is lacking water. 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 cannabis. It is extremely important to keep your root zone oxygen-rich and one reason why felt pots are so popular. And when this happens, cannabis plants will fail to uptake certain much-needed nutrients if the water levels are too great.
Just like when watering in excess, feeding with a too strong nutrient solution will cause the minerals to build up and the results will be a lockout in nutrients and a line of deficiencies to begin occurring one after another. This happens because cannabis can’t use the excess minerals and they end up burning the tips of the leaves and can end up burning the whole leaf if not dealt with fast.
As the nutrient burn continues, the tips of the leaves will start to get brown, crispy, and sometimes twisted; This is very common when using bottled nutrients, that’s why it’s a good idea to look into organic feeding if you have access to them. This is where the importance of pH levels in water comes in; Maintaining pH levels in between the acceptable range (for each specific medium) is one way to avoid this kind of problem because the pH level can block the roots from absorbing the nutrients your plant needs.
So even if you’re feeding your plant properly, higher or lower pH may prevent them from absorbing them and result in similar symptoms as overfeeding but will actually be caused due to the lack of nutrients, known as underfeeding.
When your plants are suffering from pH problems or an excess of nutrients, flushing is the best way to solve your issues, and to do it correctly, you will have to water your plants with plain pH’d water.
This will correct the pH levels and wash off the excess nutrients in the medium and the roots, allowing you to start feeding your plants from scratch or correcting the pH level, allowing your cannabis plants to absorb the nutrients they need once again.
Top Tips for Marijuana Watering
So, if you’re a beginner grower here are a couple of tips to avoid having some of the problems cited in this article.
Know when to water by weighing the pot
A good 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 overwatering.
Use your finger to check if the medium needs more water
If you are hand watering 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.
Water plants with room temperature water
It is better to water plants with room temperature water (around 20-23°C), as cold water can cause shock and encourage a cold root zone.
Water your plants when the lights are ON or up to 30min before
Avoid watering 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.
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.
first time ever growing and got some amazing colors from this strain with low temps ran it at about 58-64 for 2 weeks and got this color
A rock-solid performer who can take heavy and frequent feeding, and she will grow big fat buds in return.
This is a resilient strain that needs that extra nutrients to be able to develop the big fat nugs so make sure you feed it properly, always keeping an eye out for signs of deficiencies.
I grew this with other fast buds strains. I’m very happy how they all grew. I use soil, 19L pots on a 20/4 light cycle. They love it.
When it comes to the biggest autoflowering cultivars around, this lady is certainly up there with extra-large yields and a big thirst.
This plant grows quite big for an autoflower and thanks to its Sativa heritage, it will need that boost when it comes to nutrients to be able to develop big and strong and be able to withstand the weight of the huge amount of buds during flowering.
I got 134g off this gal growing in 3 gal pot with 24 hours of light. i’m stoked with the result! Smells like diesel. Was a great grow overall.
Another big feeder who loves a high nutrient ratio, thanks to her Indica-dominant lineage. This strain grows quite stocky and produces huge yields, that’s why you should feed her properly, and in return, it will produce lots and lots of resinous buds and in a big quantity.
Just remember that despite being heavy feeders, you should always pay attention to any signs of deficiency and increase the nutrient dose gradually to avoid stunting growth!
7. Cannabis Crop Watering FAQ
How Much Should I Water My Crop?
While there is no exact answer to this question, with experience you will get to know how much watering your crop will need. The amount needed will be totally dependent on the stage of growth, the size and types of pots used, the intensity of the light, the cultivar, the environmental conditions, the health of the crop, and the style of cultivation. Keep in mind that it is totally fine to let the plants go without water for a day or two every now and then, and is actually recommended by many experienced cultivators. The thinking behind this is that when the roots run out of water they will spread out and go searching for it, resulting in a larger overall root ball. Remember bigger roots mean bigger plants, which means bigger yields.
How Do I Tell If My Plants Are Thirsty?
As mentioned above, a great way to tell if your plants are in need of watering is by getting used to the weight of the plants. Cannabis plants themselves don’t actually weigh that much, with most of the weight coming from the water trapped in the pot. If you pick up a pot and it seems super light, it’s probably time to feed. Another obvious sign that your crop is thirsty and ready for some water is drooping and weak plants. If your plant looks like it is struggling to hold itself up then there is a good chance it needs a feed, but proceed with caution here.
Why? Well, plants that have been overwatered will display similar signs. If you feel like you have fed your crop often enough for it to be healthy and it is still looking weak and lifeless then there is a high chase that you have actually overwatered. The best thing to do in this situation is to feel the weight of the pots and to let them dry out for a day or two to see if there is any improvement.
How Much Water is Too Much Water?
When watering cannabis plants, a good rule of thumb is to aim for about 20 – 25% of the pot size. So, say you are growing in 12-liter smart pots (which is absolutely perfect for autos) then you should aim to give the plant about 2.5 to 3 liters of feed water. Another way to judge the correct amount of feed water is the amount of runoff. You do not want to water the plants until the substrate is just moist without seeing any runoff, as this can quickly lead to nutrient saturation issues.
Every time you water your plants you want to see about 15 to 25 % of the water running off. It’s also important to be able to remove this runoff, a sitting water can lead to its own range of serious issues for your crop. Be sure that you have a system in place to easily remove any and all runoff, such as drip trays. Inclined trays work great, and a wet/dry shop vacuum can help immensely.
Is There a Timing Guide for Watering my Cannabis Crop in Terms of Growth Stage?
Again, as we have mentioned above, this is really dependent on a huge range of factors. But, as a very general guide, you can aim to water your crop in the following way:
: at least twice a day, if not three times. Seedlings prefer small, frequent waterings. Do not worry so much about seeing runoff here. plants: Daily or twice daily is the best protocol to follow if you are hand watering plants that are in the vegetative growth stage. plants: Plants that are flowering require slightly less water than vegging plants, but once a day should still work well. Some growers recommend 4 times per week, with a break every third day
8. In Conclusion
Having a reference when your growing medium is the most lightweight, is a great start point for a beginner grower to work with. Finding the balance of how much your plants are drinking as well as transpiring is a learning curve that can take hands-on experience and require multiple grows under your belt.
Once you find the perfect mix, your Cannabis plants will respond in kind, and remember less is more sometimes. And remember that if you were wondering how to water outdoor cannabis, the process is basically the same but you should be extra careful on rainy days.
For those of you who have the watering game on point, feel free to leave your tips in the comment section below to help out fellow growers!