How much water your plants need, how often you should water, and what influences a cannabis plant´s water absorption rate. Watering cannabis plants may seem simple, but there is an art to it. Learn how to avoid the usual pitfalls and make the most out of any grow! Wondering how often to water cannabis or the best time to water weed plants? Check out our How to Water Cannabis Guide to get all the answers.
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!
Watering Cannabis Plants: How, When, And How Much?
Watering cannabis plants doesn’t sound like a big deal; any idiot can do that, right? Well, wrong, actually. There’s a bit more technique involved in watering weed than simply sloshing some H2O at your pots every once in a while. At least, that’s not going to do if you’re aiming for strong, healthy plants with big, beautiful buds. Watering cannabis plants is all about finding that sweet spot between giving too much water, or giving too little instead. If you approach watering marijuana the wrong way, you may cause nutrient shortages, or your plants could get sick. To prevent that from happening, this blog gives you a clear guide to wearing cannabis plants, including how much to give, when to do it, and in what way.
The Art Of Watering Cannabis Plants
Watering cannabis plants may not be the first challenge that comes to mind when ordering marijuana seeds to grow. Most people think they’ll be fine as long as you just keep their feet wet. It’s not quite that simple, though. Growers looking for strong, healthy plants should be careful about how much water they give; when they do it, and how they keep them watered. Sure, talking about the art of watering weed may sound awfully zen, but there is an art to it nonetheless. If you just keep the following guidelines to heart, it can really up your growing game.
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Why Weed Needs Water
Without water, there would be no weed plants – it’s that simple. But what do cannabis plants actually use all that water for? It seems so obvious, but here are six reasons for watering your marjuana grow – bet you didn’t know all six of them…
1) Cannabis plants are almost 90% water. They need water to keep their cells firm so the plant remains steady and upright while retaining its structure.
2) Plants need water for photosynthesis. That means without water, plants would have no energy to store, or to use for growing and flowering.
3) Seeds won’t germinate without water. As you can see, even the very first step of any grow is 100% dependent on water.
4) Water is necessary for transporting and absorbing nutrients. Although a plant’s roots absorb nutrients from the soil, they can only do so if nutrients are dissolved in water.
5) Plants use water for ‘transpiration’ so they can keep their temperature stable when it gets (too) hot.
6) Soil life needs water, and without the right life forms in the ground, many vital processes would stop working.
Right. Now that we know why we need to water our cannabis plants, let’s proceed to the best water management techniques.
The Main Danger: Too Much Of A Good Thing
Everyone knows that water is essential for a plant’s survival. What many people don’t know, however, is that too much water can harm or even kill a plant. It’s all about having too much of a good thing, really. Most rookie growers tend to give too much water to their plants rather than letting them dry out. That is why you should always be sparing in watering cannabis plants, as you’re more likely to cause problems by overwatering than by dehydrating them. In fact, for very young plants, even the splash that your average watering can produces can be harmful. There’s your first lesson on watering cannabis plants already, then: don’t damage shoots and roots by using a watering can for seedlings and young plants. The best way to go with the little ladies is to use a spray nozzle instead.
Spraying water is better for young plants.
The next tip is more of a where than a how, really. Always start watering cannabis near the stem of the plant, and work your way towards the edge of the pot from there. This encourages the plants to extend its roots outwards to all sides. A more elaborate root system equals a stronger plant with better resilience to outward influences. This applies both to plants raised in pots and to marijuana grows in open soil.
Learning When To Water Cannabis Plants
Too much or too little water can be equally bad for marijuana plants. How much water any individual plant needs depends on several factors, including the stage of its life cycle, soil type, and temperature. As a basic principle, keep in mind that cannabis plants have to be watered every two to three days. The exact watering frequency is determined by the variables listed below.
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Indoor Or Outdoor Grow?
Let’s start with an obvious one: watering outdoor grows is very different from watering cannabis indoors. Inside, growers provide every last drop of water themselves, while outdoor growers have to take drought and rainfall into account. Although this is part of the charm of growing weed in a natural environment, it does add some complications to the process (or at least, different complications). The following tips all apply to outdoor grows, with one crucial addition. Always keep close track of how much rain falls, and when, using a simple rain gauge or similar technique.
While applying the tips from this blog, always take into account what nature has already provided. In dry, hot weather, water evaporates from the plant and from the soil at increased rate. That means you’ll have to water more often. Rainy days can make watering almost unnecessary. In fact, if it keeps pouring for days on end, finding your plants some shelter can be a good idea. Obviously, that’s not going to work for plants out in the open soil, but this problem is partly offset by better drainage than your average flower pot.
Indoor grows grant much more control over the grow environment. Temperature and air humidity can be kept stable, allowing growers to curb evaporation rates. However, watering cannabis indoors poses its own set of challenges. If you forget to water your plants, there is no natural backup rainfall to save them. On the other hand, you don’t want to overwater them either. That is why indoor growers usually work by cycling from wet to dry, letting their grow medium dry out almost entirely before adding new water.
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Indoor growers differ in the level of automation they use. Some grow systems are fully automatic, watering at given times with all the nutrients added to the liquid. Others just use a watering can instead, and then there are many grow setups that are somewhere between these ends of the spectrum. Generally speaking, the less tech and automation you use, the more you should use the guidelines in this blog for careful watering of your cannabis grow.
Ebb And Flow
When growing weed indoors, watering can be arranged by using an ebb and flow setup. This involves temporarily submerging the roots of the plant, allowing them to absorb water rapidly. Usually, nutrients are already added to the water in advance, and the water is flushed out afterwards. That calls for regular refreshment of the water reservoir to deny fungi and bacteria a foothold.
Grow Medium And Watering Cannabis Plants
The soil type in which you decide to grow your cannabis affects the preferred frequency of watering. Different grow mediums have different properties. Clay, for instance, has very good water retention, while sand has excellent drainage properties. Cannabis prefers loose soil that is capable of draining away excess moisture fast. That’s why you should remember to drill a few holes in the bottom of your pots. If you don’t, water will collect in the lower soil strata, which will get you in trouble eventually.
No matter whether you grow indoors or out, the following summary lists some of the main benefits and drawbacks of various grow mediums:
(Potting) Soil: Depending on composition, soil or potting soil provides growers with rich organic soil life, good drainage, and adequate retention capacity (ability to trap moisture). Many soil types offer their own supply of nutrients, reducing the need to add fertilizer. Natural soil also has high buffering capacity, which adds stability to the grow and limits the impact of mistakes.
Perlite/ Clay Pellets: Growers often add perlite or clay pellets to their grow medium to amp up water retention capacity. This extends the wet-to-dry cycle, reducing the need to water often. Clay pellets can also help keep evaporation in check in hot weather.
Coco Fibre/ Coco Peat: Coco fibre can be used as a grow medium instead of potting soil. It is highly effective at trapping water, thus prolonging the wet-to-dry cycle. That means you should pay extra attention to remaining moisture, because the risk of overwatering is bigger
Rock wool: Rock wool is an alternative to soil used almost exclusively indoors. This fibrous material has excellent water retention power as well as good drainage capacity, which generally decreases the required watering frequency, too.
Hydroponics: Growing cannabis using hydroponics is an altogether different affair. This method involves growing plants directly in water, without using soil or any grow medium whatsoever. The water holds all the necessary nutrients if you do it right. As you’ll understand, the guidelines in this blog do not apply to hydroponic grows. You can read more about hydro grows in our dedicated hydroponics blog.
Especially when growing weed indoors, water quality makes all the difference. This is where individual approaches differ considerably, though, mainly because many weed growers only have access to regular tap water. Of course, tap water quality varies wildly between regions and countries, but generally speaking, cannabis plants can handle whatever spills from the tap. Growers living in hard water areas (where groundwater and tap water contain high levels of calcium) may want to purify their cannabis water supply to prevent mineral deposits, though. Weed can suffer from calcium and other mineral deposits. High-tech indoor growers should note that mineral deposits can damage automatic irrigation systems too.
Ideally, the purest and – according to many – best water quality comes with purified reverse osmosis (RO) water. This can be tricky to come by in large quantities, however, so we are just going to leave the suggestion here and repeat that generally speaking, clear tap or rain barrel water will do nicely.
Outdoor growers can also install a rain barrel for a water reservoir. This takes some planning ahead, but on the plus side, it can seriously cut water expenditure and ecological footprints, as well as supporting any attempt to grow weed organically. Incidentally, building your own filter for water barrels is not as hard as it may seem.
Clean, fresh water is always a good idea; however, pH values and nutrient contents are equally essential.
The Right pH For Watering Cannabis Plants
Cannabis plants can make the best use of water that is slightly acidic, at pH values (representing acidity) of about 6.5. You can use a pH meter to gauge whether your water is too acidic, or too alkaline instead. If that happens, the roots become unable to absorb the nutrients from the grow medium. That will slow down growth and could eventually be fatal. Here too, outdoor grows in open oil are less vulnerable to acidity fluctuations; indoor growers should pay extra attention to pH.
pH meters are useful tools for any grower.
Adding Nutrients, Yes Or No?
Then there is the question of which nutrients, if any, to add to the water you’re using. There are as many preferences as there are growers when it comes to nutes, but being cautious is always a good idea. Nutrient deficiency harms plant development over time. Overfeeding can cause ‘nutrient burn’, which will also prove fatal in the long run. Here too, the grow medium makes a big difference. In potting soil, for instance, many of the important nutrients are already naturally present, whereas rock wool offers no nutrition at all. As mentioned earlier, many indoor growers automatically use premixed vats of water and nutrients, with different composition for growth and flowering stages, specifically attuned to what the plants need at any given time.
The Life Cycle Stage Of Your Plants
Young plants and seedling require less water than larger, more mature plants. Generally speaking, the bigger a plant gets, the more water it needs. Yet even though nutrient requirements can change as cannabis passes from growth to flowering stage, the demand for water tends to rise stably with plant size irrespective of these stages.
Flushing Before The Harvest
Growers also use water to flush their plants before harvesting. By giving only pure, nutrient-free water in the lasts two weeks before harvest time, the plant flushes out any leftover nutrients, for a harvest that is as pure as can be.
Temperature And Light
Light and temperature also co-determine your cannabis watering regime. Generally speaking, your plants will grow more slowly in cool conditions than in warm weather. That is why a rapid-growing plant standing in the full sunshine will need more water and nutrients than a grow in colder conditions, all other things being equal.
How Much Water Does A Cannabis Plant Need?
So how much water should you give to one pant? As a rule of thumb, watering up to 25-30% of the total pot volume (the flower pot, that is) should do the trick. That gives the plant enough water to absorb all the nutrients it needs, without soaking the soil to the point where problems arise. Still, even if you know how much water to give, you’ll need to know when to water your plants for successful growing.
When Is It Time To Water Cannabis Plants?
To some extent, growing marijuana is always a matter of intuition. Good growers, however, will keep a close watch on their plants to detect just when they need a splash of fresh water to drink. For outdoor growers, the advice is not to water plants during the hot hours of the day, as the sun can easily burn the leaves at high noon. Wait until the sun starts to set, or get up early and water your plants before the sunlight hits them.
For indoor growers, the best course of action is determining their own wet-to-dry cycles. Do keep in mind, however, that plants will finish their water rations faster as they grow bigger, or if temperatures rise for instance. Indoors as well as out, paying constant attention to water conditions remains crucial.
Whether you grow inside or out, though, you can use the following simple checks to quickly determine the moisture balance of your plants:
Fingers In The Dirt
A very simple method of finding out whether your plants are thirsty is simply to stick your finger in the soil, down to about 5cm depth. You’ll feel whether the top soil stratum has dried out easy enough. Even though you won’t get all the way to the middle of the pot in this way, you will have a rough indication of whether it’s time for water yet. In normal conditions, the top 5cm of the soil will dry out in two or three days, so you’ll know when it’s time to get your hose or watering can ready.
Another method to check whether the soil is dry is to weigh your pots. Put your pots on a scale while the soil is dry. Now, water the plants and weigh again. Regular weight checks are a good indication of when it’s time for watering.
How To Recognize Water Issues
Now that you know how and why to water cannabis plants, we round up with a few water issue symptoms. That will help you detect moisture management problems early on. There is a catch, however: some of these symptoms can signal water deficiencies as well as surpluses. So if you spot the signs of water issues, always check whether your grow medium is too dry or too damp (once again using your fingers). That way, you’re making sure you don’t pick the wrong solution and kill of your grow instead of saving it!
Limp Leaves: Not Enough Or Too Much Water
Dehydrated plants lack so much moisture inside their cells that they grow limp. Be sure to check whether the soil is dry, though. This is important, because plants can go limp after receiving too much water, too. Thirsty plants will display fragile, softened leaf structures, though, whereas drowning plants have dark green, curling leaves.
If the soil turns out to be dry, water your plant right away and watch the leaves pop back up. Don’t wait too long; weed can handle a bit of a dry spell, but regular droughts will make it difficult for them to bounce back up.
Leaves Turning Yellow Or Brown: Nutrients, Water, And Balance
If your plants are chronically dehydrated, you will notice the signs in their discoloured leaves. They may turn yellow or brown on the edges, or the leaf can lose colour altogether. What actually happens is that your cannabis grow is unable to absorb sufficient nutrients, which will retard growth and prove fatal if left unchecked.
Don’t jump to conclusions, however, as yellow leaves can signal other problems than water shortages as well. Too much water can cause discolouration too, so check your grow medium before you intervene. Moreover, too much or too little nutrition can produce similar symptoms, as can light stress. That’s why you should always pinpoint the actual cause of leaf discolouration before you act.
If the leaves of your weed plants appear swollen, similar to basil leaves for example, you are probably giving them too much water. In this case, you’re fairly certain to tackle the issue by cutting back on your watering schedule. Do make sure your drainage is in order, though, as blockages can cause water to accumulate at the bottom of the pots.
Muddy Or Bone-Dry Soil
If the soil in your pots keeps looking like mud or damp clay, you are either messing up your drainage, or you are giving too much water. Add some clay pellets or similar material to your medium to improve drainage capacity. Also make sure the drainage holes at the bottom of the pot are unobstructed. A bit of gardening mesh or some pottery shards at the bottom of the pots can help prevent them clogging up.
If the top stratum of your soil resembles a patch of the Sahara Desert, chances are you’re working with dry dirt. Try to increase the water supply, but be gentle about it or you may end up drowning your plants instead.
Conclusion: Watering Cannabis Plants, Done Right
Watering cannabis plants is not as simple as you may have thought at first, then. No matter how tricky, though, it is still one of the most important parts of growing weed. In fact, it is nearly as crucial as picking the best cannabis seeds to work with. If you want to give your crop the best shot at making it from germination to harvest, be sure to water them with proper care and attention. In your expert hands, they are bound to flourish and yield the harvest you were hoping for. Meanwhile, be sure to check out our other grow blogs, because the right knowledge can help any grower get more joy and better results from every single grow!
The germination of cannabis seeds is illegal in most countries. Amsterdam Genetics cannabis seeds are exclusively sold as collectable souvenirs to customers living in countries where the cultivation of cannabis is illegal. All information on this website is intended for educational purposes only and is not meant to incentivize people to engage in illegal activities.
When is the best time to water weed plants?
Cannabis plants use a lot of water, and regardless of what sort of setup you’re using, you’re going to want to make sure you know the best time to water your weed plants.
Water acts as a vehicle for dissolved nutrients and minerals, being absorbed through the roots before spreading through the rest of the plant.
It also cools a plant down, fills up cells to keep the plant structurally sound, and is required for photosynthesis.
How to water weed plants
All plants, including marijuana, consist of about 80% water.
Therefore it makes sense that issues with water management could cause damage to a marijuana plant Outdoors.
A marijuana plant usually has enough water in the soil and from nature.
Depending on the quality and the structure of the soil, it can also help regulate the amount of moisture.
When growing indoors using pots, however, it is very easy to give your cannabis plants too much or too little water.
How to tell if a cannabis plant needs watering
There are no hard and fast rules when it comes to watering cannabis plants since the amount of water that you’ll need is based on the environment it’s growing in.
In general, water enough so that your soil is faintly moist, but not wet.
If the environment is very hot, the plant will use more water, but you should never give a marijuana plant more water than it can absorb.
If it seems like you are giving your plants a lot of water, don’t worry.
Cannabis plants can consume a lot of water.
A large portion of the water is also excreted from the plant through evaporation from the leaves.
Only a small amount of water remains behind and is used as building blocks.
Water also helps to absorb and transport nutrient salts and carbohydrates, enabling life.
Understanding how to water correctly can make a substantial difference in the quality of your harvest.
This guide will explain how to identify, schedule and deliver this vital ingredient for a growing cannabis plant.
The quality of the water you give your cannabis plants makes a difference.
Ideally, you could use filtered, or reverse osmosis water.
You may have some trouble finding reverse osmosis systems in a lot of hydroponics and gardening supply shops, depending on where you live.
Most growers simply use unfiltered tap water. Some places are blessed with pure tap water from municipal systems or wells.
However, most places in Europe and North America, are likely to have some impurities in their tap water, especially in large cities.
Regardless of the source of your tap water, most unfiltered tap water will contain extra minerals.
The type of minerals depends on your location, but Calcium, Sodium, and Magnesium are common.
The harder your water is, the more minerals it will contain.
There is a vast variety of potential minerals that your water could contain.
Some water companies know which minerals are in the water and can tell you if you ask, but sometimes they don’t.
While the severity of these impurities can vary, many growers crave precision in their operations, and tap water can sometimes have too many unknown variables.
If you are not using filtered reverse osmosis water, you’ll want to test your water to make sure it is suitable to feed to your cannabis plants.
In terms of its ability to carry nutrients (EC), tap water can have an EC that ranges from 0.2 to 0.8, or even higher. It can also have various pH levels, but water for feeding should be between 6.0 and 6.5.
The real issue here is that even when you take an accurate measurement, there is no way for you to know what sort of elements are in your water or the ratio at which they occur.
This means that all the extra money you’ve spent on expensive, carefully measured nutrients is for naught: the mix is instantly unbalanced by an unknown quantity of other nutrients.
In a worst-case scenario, this can cause nutrient burns or lock-outs and inhibit the growth of your plants.
You can also use rainwater, although it is not always better than some tap water.
If you collect rainwater to water your plants, store it in food-grade plastic containers to prevent any airborne contaminants from entering the supply.
Water temperature is also important. Your water should be at room temperature of around 20 degrees Celsius, 68 degrees Fahrenheit.
If it is too hot or cold, the roots could experience thermic shock.
Download our free Grow Bible for more information about watering cannabis plants.