CycleMadness, Created for Bikers by Bikers

Meet new Friends & Singles Nearby! Join Now!

How often do I water marijuana plants? (Viewed 1957 times)
Posts: 311
Rating: 3
How often do I water marijuana plants?
Reply #11 Posted on April 13, 2016

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, and knowing how to water your plants will save you a lot of frustration!

Watering a cannabis plant with a watering can - over or under watering are common problems, but if you follow the tips on this page you'll be watering your marijuana perfectly every time!

But 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.

Water plants when soil feels dry up to your first knuckle

How to water cannabis properly...

  1. Wait until the top of the growing medium is 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).

  2. Add water until you see 10-20% extra runoff water drain out the bottom of your pot. 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)

Some growers also use 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. Runoff water is collected in the trays and after a few minutes I suck it all up with a small wet vac.

I like watering cannabis plants with a 1-gallon water jug - easy to find, tough and convenient!

Get a Bucket Head on (or get them much cheaper locally at Home Depot)Not sure how to remove runoff water after watering your marijuana? I use a Bucket Head attachment which can be turned into a wet vac by hooking it up to any standard 5-gallon bucket. You can buy one online but it's $10-15 cheaper if you get it in person at a Home Depot!

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 your watering your cannabis plants perfectly, but it's also important to...

Make Sure Pots Have Enough 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 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

  • 16 colas on this cannabis plant - grown in a Smart PotMix in extra perlite to loosen the soil and allow water to drain through more easily.

  • Never add bark or wood chips! They are not good for growing cannabis plants. On that note, never use soil for growing cannabis that contains bark or wood chips. If growing cannabis in soil, the best soil to start with is composted super soil.

  • Use Smart pots - these fabric pots help get oxygen to your roots (which gives you faster growth) and this type of pot makes it much, much 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

Example of composted super soil - a perfect growing medium for growing cannabis since it's rich and contains lots of essential nutrients for cannabis growth
Composted super soil is 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 week or couple of days. Watering every 3-5 days is optimal. As your plants grow bigger, you will watering them more often unless you move them into bigger pots. 

If you feel like you are watering your plants too often, you can move them into a bigger pot so that it holds water for longer, a cannabis plant will be drinking a lot as she approaches harvest time.

Bigger pots = water less often

Smaller pots = water more often

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 only 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.

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

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.

Rich, composted cannabis soil with a good amount of perlite for extra drainage - starting with the perfect soil makes it easy to water your cannabis correctly every time!The reason for this is that sometimes soil and soilles growing mediums like coco coir start to form natural salts if it the fertilizers just sit in there and never get washed out.

These built-up salts can eventually cause nutrient problems, pH problems, and nutrient lock-out if they're not rinsed out.

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.

If You're Providing Extra Nutrients In The Water...

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.

It's generally a good idea to feed your cannabis plants with nutrients every other watering (at most) and provide plain, pH'ed water the rest of the time.

This will greatly help reduce the amount of salt buildup and prevent nutrition problems from occuring. 

Drooping Plants?

If your cannabis plants shows signs of drooping, chances are you are over or under-watering.

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, you should be getting 20-30% extra runoff water every time), and wait to water again until the top inch of the growing medium feels dry, up to your first knuckle or so.

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

An underwatered marijuana plant


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

An overwatered Marjuana plant Marijuana Plant drooping due to being overwatered This young over-watered marijuana plant is drooping