What Is The Best Temperature For A Marijuana Grow Room?

marijuana temperature grow room

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Temperature and marijuana plants

The temperature in your grow room is very important for the photosynthesis of your marijuana plants. For example, low temperatures reduces evaporation through the leaves. The result is that the suction force, which takes up nutrients via the roots, becomes smaller. The nutrients that are necessary, but aren't absorbed, remain in the growing medium and eventually disintegrates in the root environment. A high acidity in the growing medium reduces the working of the roots which makes the plant absorbs less water and nutrients, and the growth can even come to a halt.

So what posed as a small external imperfection at first, can have serious consequences in an entirely different part of the plant. Therefore it's very important to create a good climate in your grow room. In this article I will explain what the ideal temperature is, and what you can do if the temperature is too high or too low. Download my free marijuana grow bible for more tips about growing marijuana.

Temperature in your marijuana grow room

The temperature in your grow room depends on several factors. The location of your room in the building is an important one; in a basement it's a lot cooler than in an attic with a flat roof. Aside from that, the size of your room, the airflow, the number of lights and the extraction rates play an important role. Keep this in mind when building your grow room.

When the light is turned on, an ideal temperature for the cuttings and seedlings is between 68ºF and 77ºF (20ºC and 25ºC). As the plants get older they can evaporate a little bit more and the temperature may increase to a maximum of 82ºF (28ºC). When the lights are off, the temperature should lie between 62ºF and 72ºF (17ºC and 22ºC). Another important rule is that the temperature differences between day and night cannot be too high, a maximum difference of 10ºC. So when it's 82ºF (28ºC) during the day, it cannot go below 64ºF (18ºF) at night. A temperature difference of 5ºC is ideal. To help keep the temperature lower in an indoor grow room, consider using LED lights. To find out more about LED grow lights, click on the banner below:

Measuring temperature in your marijuana grow room

You measure the temperature in your marijuana grow room with a thermometer. There are analog and digital thermometers, and they're for sale everywhere for a few bucks. I always use a digital thermo/hygrometer with a built-in memory, so I can see what the maximum and minimum temperature was. It's also a good idea to get one with a temperature sensor on a wire, so you can hang the display outside your grow room, and can see the temperature when the lights are off.

Always measure the temperature in the shade, and at various places in your growing room. Provide good air flow by placing several fans. The lamps emit radiant heat which does not affect the air temperature. Therefore it will always be a few degrees warmer right under the lamp than a shaded spot. That is not really an issue, but make sure there's enough distance between the lamp and the plant, so the tips of the plants won't literally burn. Download my free marijuana grow bible for more tips about growing marijuana.

Lowering the temperature in your marijuana grow room


Perhaps the easiest way to keep the temperature low is by running at night. Your lamps will turn on for a few hours after the sun has set, and turn off a couple of hours after sun rise. This way you'll have your lights on at the coolest period of the day. You can imagine that if it's hot weather outside, you'll also suck this hot air into your grow room with your extractor. So, the room temperature never gets below the hot temperature outside. There are professional growers who use an air conditioning unit so they can run it during the day and at night.

Increasing temperature in your marijuana grow room.

When the lights are on, it's not necessary to increase the temperature. The lamps themselves will take care of that. However, it is important to distribute the air over your room evenly so that you'll get the same temperature everywhere. Use swivel fans for this, and aim them between the lamps and the plant. Fresh air from outside should also be well distributed over the growing area, so that there won't be any cold spots. Especially in winter when temperature can get below freezing.



Source: ILoveGrowingMarijuana.Com