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How much water do cannabis plants need?

The cannabis plant is a flexible plant that generally can recover after too much or too little water and after under or over fertilization. When this happens regularly this will have harmful effects, which can result in a low yield, a less good taste and even the death of the plant. Most novice growers use earth, therefor we take this as the starting point for the information on this page.

Watering cannabis plants.

The amount of water that a cannabis plant needs depends on various factors:

  • Is the plant in the ground or in a pot? How big is the pot. Has it rained the last few days?
  • How is the climate? The number of sun hours, the temperature and the air humidity?
  • Thekind of cannabis? (Sativa or Indica). Haze cannabis (Sativa) needs more water during the flowering period than Kush (Indica).

Some tips for beginners:

  • The best temperature of the water is around 19 degrees Celsius.
  • Stick a skewer about 4 inches into the earth. Remove this stick every day and when the tip is dry the plant can use some water.
  • Germinated cannabis seeds and seedlings do not need nutrition. In most soil there are enough nutrients to get through the vegatative phase.
  • Give water to young seedlings long the edge, so the roots actively search for water which results in a firmer root system.
  • Water your plants in the morning or in the evening. When growing indoors water your plants when the lamp turns on. At the hottest time of the day, the water will evaporate faster.
  • Do not spray water over the plants, water with nutrition may damage the leaves. Unless you use foliar nutrition such as Plagron Vita Race.
  • Leaving your plants dry every now and then has a big advantage for the entire metabolism of the plant, this provides extra oxygen in the soil and benefits the development of roots.

Giving the cannabis plant too much water.

Never give your plants too much water. Sometimes if a plant is over watered, they may not recover afterwards. The leaves start to get dull and turn yellow. You try to correct the watering issue but nothing seems to help. Chances are, your plant is suffering from root rot. This will seriously damage the plant. If the roots of the plant are in too wet a soil for too long, they will rot. Root rot (pythium) is difficult to treat. Too high humidity increases the chance of fungi and bud rot. If your plants are in pots, make sure there is a hole in the bottom of the pot so that the excess water can run away.

Image of a Cannabis plant that has received to much water Image of a Cannabis plant that has received to much water

In the case of a cannabis plant that has received too much water, the leaves will go limp, after a time the leaves wilt and turn yellow and brown.

A cannabis plant that has received too little water will try to stop the evaporation of water. The weed leaf will start to curl up and fold up, as it were. After a while the leaves will also hang. The leaves will also curl when the temperature is too high or the ventilation is hard.

Cannabis plant with to little water Leaves curling up because of the ventilation Leaves curling up because of the ventilation closeup

How often do you water the plants

A seedling or young cannabis plant needs only a small amount of water. At high temperatures (for example in indoor cultivation) you can give a small amount of water twice a day. When the plant is more mature, you can raise the amount of water and reduce the frequency. In a weed plant in bloom you can water every 2 days and sometimes even every 3 days. Measuring the soil is key, check the ground every day.

Flushing your cannabis plants for better taste

Rinsing your weed plants is actually adding an overdose of water to flush out the accumulated nutrients in the soil. This is not without risk but can be a solution if you have over fertilized the plants. A better way is to stop feeding the last 2 weeks of flowering. This has the same result as rinsing but without risk. Rinsing your plants provides a better taste of the cannabis.

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