How much water do weed plants need daily and how often should I water my weed plant? These are questions we often receive from starting and aspiring growers.
Whether you grow weed plants in soil or some other growing medium such as coconut coir, watering cannabis plants is an important consideration that is vital to the success of your crop. Cannabis plants cannot survive without water, but when the compost is too wet, oxygen cannot get to the roots, which causes them to choke.
It's rather vital to make sure you to give the right amount, at the right times when you are watering cannabis plants, from the seedling stage to the flowering stage. In this guide we dive deeper in the topic of keeping your weed plants hydrated, and answer all the questions you might have.
How much and how often do I have to water my cannabis plant?
How often and how much water you have to give to your cannabis plant is usually hard to describe. It isn't an exact science. Autoflower seeds generally need less water and can handle a mistake or two more easily when compared to feminized seeds.
Yet, no matter what type you choose when you buy weed seeds, if you do not give enough water to your cannabis plants, they will start to sag, and the growth or flowering will slowly stop. It is, therefore, important that your marijuana plants receive sufficient water, on a regular basis.
If you usually wait until the leaves hang limp before giving water, your marijuana plant will experience stress, resulting in delays in the development of your plants. How often and how much water you need when you water cannabis plants depends on the following two factors:
The size of the pot
The weed plant pot size ultimately determines how often you have to water your weed plant. A large pot with soil dries out much less quickly than a smaller pot with soil, so you will have to water weed plants more often to prevent dehydration. It is important that you regularly feel the earth to see if it is damp enough.
Using a small pot when growing cannabis means that the earth in the pot will heat up much faster, which will cause your earth to dry out extremely quickly. It can dry out so quickly that your pot will be completely dry after 12 hours.
Temperature in the grow room
The higher the temperature in your grow room, the faster moisture will evaporate and, consequently, the moisture in the soil. Since (indoor) weed plants like higher temperatures, there is a good chance that it will be warm in the grow room.
Most of the heat from the grow room comes from an HPS lamp. The higher the wattage of an HPS lamp, the more heat it emits.
Related article: Best temperature and humidity to grow weed
When to water your weed plant?
Knowing when to water your cannabis plant is an art that combines attentiveness, touch, and an understanding of your plant's needs. Just like everything in life, a balance must be struck. Make sure the moisture levels in the soil are not too dry or too wet. Both can be detrimental to your plant's health.
The soil should never be completely dry and crumbly, but neither should it resemble a muddy swamp. Finding the sweet spot in between these two extremes is key to maintaining a happy, healthy cannabis plants.
A simple yet effective method of assessing soil moisture levels is using your own hands. Touch the surface of the soil, feeling its texture and moisture content. Is it dry and loose, or does it hold together? Does it feel parched, or is it damp?
To be sure, you can put your finger in the soil, about an inch or two (up to 5 cm). This will give you a better sense of the overall moisture level below the surface, where it matters most for your plant's roots.
If the soil at this depth feels dry, it's a clear sign that your weed plant needs watering. On the other hand, if it feels saturated and waterlogged, hold off on watering for a while to let it dry out a bit.
Understanding how water behaves in the soil of your cannabis plant pot is essential for maintaining their health. When the top layer of soil dries out, your marijuana plants can lose their ability to absorb water effectively. This is evident when the water you pour in swiftly drains out the bottom of the pot.
If each of your pots sits in its own dish, this isn't much of a concern, as the soil can gradually absorb the water from beneath. However, problems can arise if your plants are all situated in a shared drip tray. In this setup, water tends to gather at the lowest point, causing the plants located there to soak up the excess water, depriving the others.
This can result in some of your weed plants ending up parched, while others might be overwatered. This issue often goes unnoticed by growers initially, but can eventually lead to significant plant health problems.
To prevent this, you can do the following: provide a separate dish for each plant, ensuring that each has their own water source. Alternatively, you could water your plants in stages, allowing the water to be absorbed gradually before adding more.
Another solution involves the use of a surfactant, such as a drop of liquid detergent, to reduce the water's surface tension and thereby improve the absorption into the soil. Be mindful, though, to use only a tiny amount and not too frequently, as excessive detergent can harm your cannabis plants.
Keep in mind that there isn't a one-size-fits-all when it comes to water plants. Their water requirements vary depending on their growth stage and environmental conditions. However, your plants will give you clues about their hydration needs if you know what to look for. Stay tuned into these signs and adjust your watering practices accordingly.
Here are three techniques that can be used to ensure your cannabis plants are given just the right amount of water for their needs.
Method 1: Use your finger
Evaluating the moisture level in your cannabis plant's soil can be as straightforward as dipping your finger into it. If you find soil clinging to your finger after you've probed the earth, it's a clear indication of residual moisture. This is because water combines with soil to form mud, and mud sticks!
Although the surface of the soil may appear dry, the presence of moist soil on your fingertips reveals that there's still water beneath that dried-out layer. You can also a skewer, in case you don't like getting your hands too dirty. When inserted into the soil, it will darken if moisture is present, giving you a clear visual cue without the risk of damaging the plant roots.
Here's a pro-tip for when you are growing marijuana: Always use lukewarm (tap) water for watering your plants. To ensure this, let the water sit for a few hours after drawing it from the tap. This waiting period allows potentially harmful substances like chlorine to evaporate, ensuring that your cannabis plants receive water that's free from unnecessary chemicals.
Method 2. Lift the pot regularly
One of the most effective yet underutilized techniques to gauge the water needs of your marijuana plants involves simply lifting the pot. This method, while straightforward, does require a consistent and regular approach. Here's how to do it: each time you water marijuana plants, make a habit of lifting the pot both before and after the process.
You'll soon notice a distinct difference in weight. The added water increases the weight of the pot, a change that becomes more noticeable with each watering session. With a few weeks of practice, your sensitivity to these weight variations will enhance, and you'll be able to accurately estimate how much water your cannabis plants require at any given time.
Many seasoned growers have honed this skill to such an extent that they merely need to lift a pot to determine if you they need to water cannabis plants. This intuitive understanding, developed over time, allows them to cater precisely to their plant's hydration needs, without writing out an entire watering schedule.
Method 3. View the appearance of the leaves
Your marijuana plants are like babies, they can't exactly ask you to give them the water they need. Your plants however can provide valuable cues. The leaves, in particular, can serve as a reliable indicator of your plant's hydration status.
Pay attention to the orientation of the leaves. Are they reaching towards the sun, their tips angling upwards? If so, these are positive indicators that your plant is content with its current growing conditions.
However, if you notice the leaves drooping or hanging lifelessly, it's a signal you might need to change something about their watering schedule. The leaves may be responding to either an excess or a deficit of water.
Under watered plants typically have leaves that feel thin and fragile to the touch. This is because the lack of water leads to a reduction in the plant's cell turgor pressure, making the leaves appear wilted and feel delicate.
On the other hand, overwatered plants often have leaves that are unusually thick. This is because excess water is stored in the plant tissues, leading to a bloated appearance.
So, take the time to observe your plants closely, particularly the condition and behavior of their leaves. By doing so, you'll gain insights into their hydration needs, enabling you to water them appropriately. In the end, this careful attention to your plants' signals can contribute significantly to their healthy growth and development.
Method 4: Use a moisture meter/tensiometer
Another convenient method is using a moisture meter to measure the soil's water content, however it may not always yield reliable results. Relying solely on a gadget can cause long-term complications, especially in an activity as hands-on as growing cannabis.
It's important to cultivate a personal understanding of your weed plants' needs, which includes being able to determine manually how much you have to give when you water cannabis plants. After all, what happens if your moisture meter's battery dies? How will you assess your plant's hydration needs then?
Here's a helpful tip for your gardening journey: If you notice the soil in your pot is dry and contracted, or if water seems to run along the edges and straight out the bottom, the soil may be too dry to absorb water effectively. In such cases, start by adding half a liter of water to allow the soil to expand and regain its capacity to absorb moisture. After waiting for about half an hour, proceed to water your plant as usual.
Another tip for those who use certified organic nutrients and introduce beneficial fungi to their soil: Your soil may need to remain slightly more moist compared to those on a mineral diet. These fungi and bacteria rely on moisture to thrive and multiply.
The fungi, particularly those involved in the formation of mycorrhizae, also retain and require moisture. It's crucial to avoid letting your carefully crafted 'living soil' dry out too much, as it could compromise the health of the beneficial organisms within it, which would be a real loss.
Create nutrient water
When preparing nutrient water for your cannabis plants, it's essential to adhere to the proper procedure and ensure the water reaches the optimal temperature. Unlike most human beings, your plants do not like to drink very cool (tap) water.
If the water is significantly colder than the surrounding air, it is possible the plant can experience temperature shock. Which can even result in the death of your beloved weed plant. Conversely, water that is too hot can impede the roots' ability to absorb oxygen. Water temperature also plays an important role in determining the pH value.
To avoid these issues, it's best to give the water ample time to adjust to the grow room's temperature. Consider leaving it in the room overnight, allowing it to gradually reach the desired temperature. By doing so, you're not just watering cannabis plants; you're working towards a wonderful harvest!
Related article: Guide to Nutrients for Weed Plants
How to give the water?
If you're managing just a handful of cannabis plants, a watering can might serve your needs perfectly. These tools are quite efficient for small-scale cultivation, but their capacity can limit their utility when dealing with a larger number of plants, given the constant need for refilling.
To nourish your plants, opt for a feed that's specifically designed for tomato plants, as their nutritional needs closely mirror those of cannabis.
For larger grows, consider a hosepipe attached to a sizable container. This setup allows you to add nutrients directly to the water and ensure it reaches the appropriate temperature before application.
To manage excess water, place your plants on trays or saucers. This setup makes it easier to remove any surplus water and prevents your plants from sitting in a puddle, which could lead to health issues of the root system. Trays offer the added advantage of handling multiple plants simultaneously, making them a convenient option for larger grows.
Regardless of the size of your grow, make sure your pots or containers have ample drainage holes. Proper drainage is crucial to prevent water accumulation, which could lead to root rot.
On a side note, you will need to water your plants more often when you are just starting your grow. Young cannabis plants typically require more frequent watering compared to their mature counterparts. To stay on top of their needs, make it a habit to check the soil every two to three days.
What have we learned?
In this comprehensive guide, we've navigated the essentials of watering cannabis plants, exploring factors like pot size, grow room temperature, soil moisture, and plant cues. We've delved into techniques like the finger method, pot lifting, leaf observation, and moisture metering, stressing the importance of balance and attentiveness.
Additionally, we examined the benefits of using trays for excess water management, ensuring proper drainage, and employing nutrient-rich feeds, highlighting the particular needs of young versus mature plants. Ultimately, cultivating a deep understanding of your marijuana plants' hydration needs is a critical step towards a successful grow, fostering healthier plants and promising a bountiful harvest.
To learn more about taking care of your weed plants, you can find more articles like this in our Learning Center. If you are an aspiring cultviator, trying to get the most out of your first grow, you can not go wrong when you grab one of our weed seeds for beginners. Keep our beginners grow guide in the other hand and you should be golden!