• Post last modified:October 10, 2021
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Leaning how to water marijuana plants correctly is essential because it delivers nutrients to the plant and also aids in the production of photosynthesis thus allowing the plant to grow.  So if you want to produce good quality bud you need to know precisely how and when to water your plants. There is no straight forward rule to watering them as this will massively depend on what medium they are growing in and what the environment is like, if they are in a hot dry environment then they will require lots more water then a warm humid environment.

How do I know when to water marijuana plants?

The answer is simple, you water them when the soil feels dry up to around 1 inch.

  1. Wait until the growing medium feels dry in roughly the first inch of soil.
  2. Water the plant until you begin to see some water running out the bottom, allow only a little to run out the bottom of the pot.
  3. Clean up any run off water.
  4. If the water takes a long time to come through then you either have not poured enough water or you could have a draining issue (see below).

How to water marijuana seedlings

It is just as important to properly water your seedlings, remember seedlings are very delicate so too much or too little water can easily kill them. Seeds don’t have any roots so let them dry out and it can kill them, equally over watering can drown them. Ideally you should keep them moist but not wet, you can do this by spraying them with a mist instead of pouring water over them, this prevents the risk of over watering.

As the plant grows you can begin to water it, make sure you keep an eye out for any signs of mold as this can easily kill a plant and is common in the hot humid environments that are created in a grow room. If your soil is wet and you are worried that you have over watered then allow the soil to dry out for a few days, this will allow the plant to absorb all the water it can and any excess water to drain off preventing the risk of mold developing.

​Top tips for Improving drainage

It is very important to have good drainage as this is one of the major causes of mold and bacteria build up and if a plant becomes waterlogged it can cause damage to its structure which will then begin to droop.

To improve drainage follow these simple rules:

  • how to water marijuana plants correctlyMake sure your pot has holes in the bottom for drainage or use a fabric pot (image right) these are made with a breathable cloth like material that allow the water to come out of any part of the pot and also assist with getting oxygen to the roots. 
  • Add perlite into your growing medium, this creates tiny air pockets in the soil and keeps it loose allowing water to drain more effectively.
  • DO NOT use wood chips or bark, they are notoriously bad for growing marijuana and can retain water allowing mold and bacteria to build up.
  • Make sure you water the plants slowly and evenly, by this I mean do not pour the water fast in one corner of the pot, pour it evenly around the entire surface of each pot. If you pour the water in just one part of the pot it can create channels through the soil which then allows the water to drain through the pot too fast not actually giving the plants roots enough time to absorb the water it needs.
  • Water in the morning – Ideally you should water the plants in the morning if outside or when the lights have just turned on if inside. This means the plant has an entire day of sunlight ahead of it and plenty of water on board to help it carry out the process of photosynthesis. Watering in the morning also reduces the chances of mold building up.
  • Use a larger pot (once the plant is big enough to be repotted) – If you use a larger pot than needed not only will it give the plant ample room for growth, but it also will save you lots of time as the plant gets bigger. This is because larger pots can retain more water and therefore you can afford to water the plants less frequently.

Growing with compost​

When growing with compost or any amended soil such as super soil you will not need to add nutrients into the water because they will be provided automatically by the soil. Make sure when you are watering and using this soil that you do not allow too much run off as this will cause the nutrients in the soil to drain out of the pot and go to waste. If you are adding the nutrients into the water manually then don’t worry about a little run off, this will actually assist in preventing nutrient build up in the soil.

Signs of over or under watering​

To prevent over or under watering make sure you are getting around 10-20% run off each time you water and make sure your plants are watered evenly, if you wat er lots in just one corner of the pot the water can easily drain through without the plant absorbing enough eventually causing under watering.

Under Watered  

  • Plant and leaves become droopy and limp (see image on right).
  • Leaves are dry and crispy and not as rounded.
  • Leaves feel dry and thin.
  • Soil is very dry to the touch

Over Watered 

  • Plant begins to droop and leaves begin to curl downwards.
  • Leaves feel firm and are well rounded
  • Leaves can begin to turn yellow
  • Soil is still damp to the touch

Watering your plants correctly is vital to their health, equally important is providing the right nutrients to allow them to thrive, have a read of our comprehensive guide to nutrients or how pH effects cannabis plants.

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