Are you new to growing cannabis? Have you been wondering about the best ways to water your plants? Learn more about some of the best practice for watering marijuana plants to ensure your harvest is bountiful! Water plays a crucial role in keeping your marijuana plant healthy. Get tips from the experts at Leafly to keep your weed plants hydrated, and learn how to flush them properly. Buy Quality Marijuana seeds at Amsterdam Seed Supply – How often should you water Marijuana Seeds? – ✓ High Quality Strains✓ Award winning genetics
Tips for Watering Your Cannabis Plants
“W ater = Good” is a basic equation for all life on this Earth.
That may be why many first-time growers tend to overwater their cannabis plants. After all, if “Water = Good,” then “More Water = Better,” right? Isn’t that how you fast forward that transition from “newly planted seedling” to “leafy bestower of nugs?” Not necessarily.
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Whether you’re watering a cannabis plant or smoking it, moderation is always key. Overwatering your cannabis can lead to detrimental conditions like root rot, halt its growth entirely, or even kill the plant.
That’s why PotGuide is here with some helpful tips for watering your cannabis plant.
Dangers of Overwatering Your Cannabis Plant
Overwatering your cannabis plant submerges some of its most vital organs; the roots are like the plant’s brain and lungs. The roots can “drown” by being unable to pull enough oxygen from the surrounding soil. Too much water may also cause “root rot,” where an infection takes hold or vital nutrients are washed away. This will cause yellowed leaves and twisted or brown roots.
Proper pH Levels for Watering Cannabis
If you want your plant to focus its energy into producing resinous buds, you’ll need to reduce distractions and stressors like improper pH levels. (pH stands for percentage of Hydrogen, and refers to how acidic or basic a solution is.)
Regular tap water works fine for watering your cannabis plants as long as you leave it out for around 24 hours so that its pH levels balance. As an added benefit, water at room temperature won’t shock your plant. Purists may want to filter their water first.
After 24 hours, use a basic testing strip to check the pH level. These strips can be ordered online or bought at hardware/home supply stores. Using a pH-down solution, you’ll need to adjust the pH level of your tap water to whatever the specific needs of your soil are.
In general, the pH level for regular soil ranges from 6.0 to 6.8. Other grow mediums may need their levels to be between 5.5 and 6.0. Your garden supplier will know the correct pH level for the medium you choose to grow in so feel free to ask, and even experienced growers will tell you that finding the right levels for a given strain might take some adjustment as you go.
Using the Right Planter
Your first pot should be large enough to let your plant grow into, with plenty of room for root expansion (moving the plant is stressful to it, and should be avoided). Pots should also have enough holes at the bottom for drainage. You don’t want water collecting at the bottom of the planter where it can oversaturate the roots. You can buy grow pots specifically for cannabis, but a standard 5-gallon plastic bucket from the hardware store and an electric drill will do the job just as well.
Once your seedlings have started developing into plants, you’ll need to start adding nutrients. These can upset your plants if introduced too early or too rapidly, so start slow. Add about half to ¾ of the amount recommended on the product label to your water, then slowly increase over the next week or so until you reach the full recommended amount.
Anything over the recommended amount can cause “nutrient burn.” You’ll know if nutrient burn is happening by the brown or yellow discolorations on your leaves. To fix it, flush the nutrients out of the soil and continue using only the recommended amount. We’ll cover flushing soil at the end.
Watering Cannabis Seedlings
Cannabis seedlings are thirsty and can dry out quickly. Depending on the humidity and the soil you’re using, you may need to water them up to twice a day. However, only use a little water each time, preferably from a mister, to lightly dampen the soil. Too much water and you could disturb those delicate root systems.
Watering Matured Cannabis
Your watering schedule will depend on the grow medium you’re using as well as the environmental conditions. In general, you’ll want to water cannabis plants every two to three days. It’s best to water them in the early morning, or whenever your grow lights click on. This both improves nutrient absorption and reduces the risk of mold.
Larger cannabis plants can go a couple of days without being watered. In fact, it’s healthy for them to dry out a little, since this allows the roots to expand as they absorb oxygen and burrow for water. But, if your plant gets too thirsty, the stress can turn it hermaphroditic so keep an eye on it.
You’ll know if your plant is thirsty if its leaves are pale and wilting. On the other hand, if you’ve overwatered your cannabis, the leaves will be dark green and claw-like as they curl and bend downwards. Neither is preferable, but underwatering is healthier for the plant than overwatering cannabis.
A good rule of thumb (or finger in this case) when it comes to watering is to poke your index finger into your grow medium. Stop at your first knuckle, or about 5 cm deep. If the soil feels dry, it’s time to water. If it’s wet, check again tomorrow.
How To Water Cannabis
This part’s easy. Fill a watering can with your nutrient-rich, pH-balanced water, then pour it evenly over the entire surface of your grow medium. Start from the center, then work your way out to the edges. This will encourage the roots to spread out and send nutrients throughout the pot. Keep watering until you see excess water draining out the bottom. To ensure an even spread of nutrients, about 20% of the water you poured should drain back out.
If your water takes several minutes to drain out, or if your soil is still wet after 3-4 days, you probably have a drainage issue.
Flushing Your Soil
Two weeks before you’re ready to harvest, change up your watering technique and start flushing your soil. To flush your soil, pour a healthy amount of room temperature, non-nutrient enriched water over your grow medium. Wait a couple of minutes for the water to absorb excess nutrients, then flush it again. The plant will absorb any remaining nutrients during that time.
By flushing away nutrients and only using pH-balanced, purified, room temperature water for the final two weeks, you’ll end up with better tasting nugs and less harsh smoke (or so it’s believed). Some people don’t believe in flushing, but most growers will tell you it’s a necessity.
The Wrap Up
It’s easy to get over-enthusiastic about watering cannabis when you’re first starting out. However, much like with people, moderation is key. By following our tips for watering your cannabis plant, you’ll end up with a healthy plant that’s happy to give you back some dank nugs in appreciation.
Frequently Asked Questions
How Often Should Cannabis Plants Be Watered?
Around every 2-3 days, or twice a day if its a seedling
How Can You Fix Overwatered Cannabis Plants?
Hold off on watering again until the soil feels dry when you poke your finger into it up to the first knuckle.
Is It Better to Overwater or Underwater Cannabis Plants?
It’s better to err on the side of underwatering. If you under-water you can always add more, but if you add too much, you’ll have to wait for the soil to dry out and for the plant to process out the excess.
Any tips and tricks for properly watering your cannabis plant? Anything we missed? Share in the comments!
Paul Barach is a Seattle-based freelance writer, editor, and author with experience creating well-researched, edited web articles covering cannabis news, culture, history and science. Paul is a regular contributor to PotGuide and has also contributed to publications such as Medium.com, SlabMechanix, Litro, and The Trek. He prefers to spend his free time outdoors and most recently hiked the Pacific Crest Trail. So far he has only fallen into the La Brea Tarpits once. You can follow him on Instagram @BarachOutdoors and stay up to date professionally through his LinkedIn page.
How to water and flush marijuana plants
Like all plants, cannabis requires water in order to perform its basic functions. Water helps plants absorb nutrients from the soil and then moves up the plant and into the leaves, and without it, the plant can’t survive. But giving a marijuana plant the proper amount of water may be more difficult than you think.
There isn’t an exact science for watering a weed plant. You can’t observe the roots in most cases to see if they need water. Also, a plant is constantly growing and the climate it’s in will fluctuate, so the amount of water it needs constantly changes.
Here are some tried-and-true tips to keep your weed plants healthy and properly hydrated.
How often should you water marijuana plants?
A common mistake first-time growers make is to overwater marijuana plants. A cycle of wet and dry is healthy and necessary for the roots of a plant to grow out and reach deeper into the soil.
Additionally, roots pull in oxygen as soil dries and when soil is too wet, the plant can’t pull in oxygen efficiently and essentially can’t breathe.
Below are general estimates and are meant to give growers a rough sense of frequency of waterings; if a plant needs water and it falls outside of these ranges, water it.
|Plant stage||Water every # of days|
How to tell if a cannabis plant needs watering
The best ways to tell if a weed plant needs water is to:
- Stick a finger 1-2 inches into the soil—if it’s wet, hold off; if it’s dry, it’s time to water.
- You can also pick up a pot and feel its weight to determine if it needs water. This will take some experience—be sure to lift up your pots after watering to get a feel for how heavy they are when full of water. This will also give you a sense of what a light, dry, plant feels like.
An under-watered marijuana plant looks droopy and weak, with yellow or brown leaves; there is no strength in the leaves and they look lifeless.
Leaves of an overwatered plant look slightly similar in that they droop, except the leaves will be dark green and the leaf tips will be curled.
Note how often you water plants and write it down in a log. Get your marijuana plants on a watering schedule—as they grow out of the seedling stage, watering every two to three days is ideal.
Keep in mind that as plants get bigger, they will need more water and need to be watered more frequently.
When growing weed outdoors, you’ll need to water more often as the weather gets hotter and less often as it cools.
When you find the sweet spot between too wet and too dry, your plants will flourish.
How much should you water marijuana plants?
The amount of water your marijuana plants need depends on a few factors:
- Size of plant
- Outside temperature
- Overall health
- Stage of growth
You want to water a plant enough to soak all the soil in the pot. Water should pool up on the surface of the soil when you’re watering, and come out the drainage holes in the bottom of the pot after a couple seconds. If water sits on the surface of the soil, that means it’s too wet and doesn’t need more water.
If a weed plant is very dry, water will run straight through the soil and pot and quickly come out the drainage holes. If this happens, water the plant a little bit and then come back to it after 15-20 minutes and water it again, and maybe even a third time. This allows the soil to slowly absorb water until all of it is thoroughly wet.
Roots are constantly on the hunt for water as they grow and stretch out. As a plant gets bigger, so should the watering radius—the area around the stalk of the plant that you water. Doing this will help guide roots to the edges of the pot as they seek available nutrients in soil.
Watering too far away from the roots can create standing water, which can lead to root rot, mold, and pest issues.
Is your container the right size?
To properly water a cannabis plant, it needs to be in the correct size container, or a big enough hole if it’s in the ground. If a pot is too big, the plant’s roots can’t drink water where they don’t reach. If the roots aren’t absorbing water, water will sit in soil and take a long time to evaporate, which can promote root rot and unwanted insects and fungus.
Conversely, if a container is too small, the roots won’t be able to stretch out, which can stunt the growth of a plant. Less soil also meant you’ll need to water the plant all the time, which will add labor.
Ideally, cannabis plants should start in a small pot and progress to bigger and bigger pots as they outgrow each container. For example, you can start a seedling or clone in a 4″ or 1-gallon pot, then move on to a 2-gallon, 5-gallon, 10-gallon, and so on.
Plants are ready to transplant when a healthy root structure encompasses most of the soil and the roots aren’t bound. When transplanting, take time to look at the quality of the roots: Bright white roots with a strong, thick structure is a sign plants are getting watered correctly.
What is flushing?
Flushing is an important part of the marijuana growing process, when you stop giving a marijuana plant nutrients and give it straight water. This is done to flush out nutrients that may have built up in a plant during its life.
Flushing is done for about a week before harvest, at the end of a plant’s flowering stage when buds are almost ready to cut down.
A flush can also be done to clear plants of nutrients if they have a nutrient imbalance, such as nutrient lockout, when your plants are overloaded with nutrients and unable to absorb new ones.
How to flush weed plants
Flushing marijuana plants before harvest
The final flush should occur for a week or so before you cut down weed plants for harvesting. Water your plants with the same amount as you normally would, but only with water. This will force the plant to use the nutrients stored within it—if its nutrient reserves are not used or broken down, it could affect the quality of your harvested buds.
By looking at the trichomes on marijuana plants, you’ll be able to tell when the plants are ready for a flush—begin when they start turning milky.
Different growing mediums require different flushing timeframes before harvest:
- Soil: 7-10 days
- Rockwool and coco: 7 days
- Hydroponics: 5-7 days
If growing in amended organic soil, it is not recommended to flush plants. This is because the soil already holds all the nutrients the plant needs to thrive, and by flooding the soil you can wash away and damage the complex ecosystem that you’ve worked hard to develop.
When to stop watering before harvest
Water your marijuana plants as normal when in the flushing phase—don’t let them get too dry or too wet. Make sure not to harvest dry or wilting weed plants—they should be nice and healthy when you cut them down.
How Often Should You Water Marijuana Seeds?
After the hassle of choosing a seed and getting it to sprout then grow, another of the big questions is how often should you water marijuana seeds until they germinate. You should not water marijuana seeds once you place them to germinate in a warm moist place. If you give your marijuana seeds water very often you will drown the seedling and it won’t be able to crack out of its seed.
Now that the Marijuana seed has germinated, how often should you water Marijuana seeds?
Once it germinates though, how often you should water marijuana seedlings varies according to the temperature of where the marijuana seeds are growing, but as a rule of thumb, you should water the marijuana plant once the soil is dry. An easy way to tell is if you try and lift the edge of the pot with one finger; if it feels “light” then it’s time to water, if not then leave it a few more days to evaporate and check back often to water. Usually, when you follow this technique, it helps with the formation of trichomes on your marijuana plants during the flowering phase which is equal to dank-er flowers.
You might also find our FAQ submission How Do I Feed A Plant? useful!