The right temperature when watering cannabis plants

The temperature of the irrigation water is often not given enough attention, be it for hydroponic growing or for growing on soil. Yet this is an important factor that contributes to the development of the root system.

If the nutrient solution in the tank has too high a temperature, this can lead to further problems and incorrect diagnosis. As a result, cannabis plants may root poorly, grow slowly or not at all, and flowers may develop sub-optimally.

Tap water can have a different temperature depending on the season. A hose used in the garden can heat up quickly in the sun and the water in it becomes hot. In winter, the water from the tap may be freezing cold. But what exactly happens if the water is not at the right temperature when watering or irrigating? What is the best temperature? You can find out more about this below.

Flowers develop poorly and remain small if the temperature of the watering water is too low.

Watering water that is too warm

In certain climates and growing conditions, watering water may become too warm. This problem does not occur as often as water that is too cold. If the watering water is too warm, the overall development of the plants is slowed down and nutrient uptake is significantly disturbed by the lack of oxygen in the watering water/nutrient tank. The problem can only be remedied by regulating the temperature of the watering water and the root area and bringing it to a good level.

Watering too warmly promotes fungal diseases in the root area and can subsequently kill the whole plant. In any case, it should be avoided that the roots come into contact with hot water. Water that is too warm in the nutrient tank can occur especially in the summer months. Then the matter can best be solved with air conditioning in the growing room, increased ventilation and/or the use of a cool tube reflector. There are also water coolers that keep the temperature in the nutrient tank at the desired level.

Avoid the root area becoming too hot or coming into contact with hot water.

Water too cold

Cannabis roots develop excellently in a nutrient solution that is enriched with oxygen and has the right temperature.

Often the water used for watering is too cold. In many areas, the (cold) tap water is not warm enough for watering for many months of the year. If the cannabis plants receive water that is too cold, the leaf stalks and stems first turn purple, which in many cases is due to a phosphorus deficiency. At 15° C, phosphorus is only poorly absorbed, at 10° C not at all. Growth stops and a short time later there is also a magnesium and nitrogen deficiency.

In the flowering period, the buds develop worse due to too cold watering, remain smaller and form many small leaves in between. The problem can easily be solved with a thermometer and the addition of warm water. Set the right mixture of cold and warm water and then use this water for the plants.

Oxygen and water temperature

Water consists of hydrogen and oxygen. However, the amount of oxygen contained in water can fluctuate and depends, among other things, on the temperature and atmospheric pressure. The amount of oxygen contained in the water is of great importance for cannabis plants, because it determines the nutrient absorption capacity of the root system. The roots, in turn, are crucial for the overall development of the plants. For this reason, in deep water cultivation and also in other hydroponic systems, the water in the water tank must be enriched with oxygen with the help of air pumps and bubbling stones. Plants that receive oxygen-enriched water, which is also at the right temperature, perform better and produce more.

The oxygen content of the water can also be reduced by a high occurrence of bacteria.

The ideal irrigation temperature

Plants develop best when watered with an irrigation temperature between 20°and 25° C. At temperatures of 19° the roots can develop even better and the maximum nutrient uptake takes place at 23° C water temperature.

For better results, not only the water temperature should be adjusted, but also the irrigation water should be enriched with additional oxygen. Even if you are not growing hydroponically, it makes sense to enrich the water with oxygen. This can be done with a small Air pumpThis can easily be done with a small watering can, a thin air hose and a bubbling stone. Hang the bubble stone in the watering can for a few minutes and switch on the air pump.