Regulating and Maintaining Reservoir Temperature

By Matt LeBannister
Published: December 27, 2016 | Last updated: April 21, 2021 07:18:46
Key Takeaways

Maintain your indoor gardening reservoir’s ideal temperature and you’ll soon be watching your plants thrive.

There are many factors that must be regulated when gardening indoors. One of the most difficult elements of indoor gardening to control is the temperature of the nutrient solution in your reservoir.


The ideal temperature of the solution is important. It regulates the amount of oxygen the water can hold, the reproduction of harmful root-born insects, the metabolicrate within the plant, and it can also affect the concentration of nutrients present as evaporation takes place.

There are many ways to regulate and maintain the ideal nutrient solution temperature in your reservoir to be between 60 to 75°F. Maintain the ideal reservoir temperature and watch your plants thrive.


Problem: Nutrient Reservoir is too Cold

Solution: Often we might find that the nutrient solution in our reservoir is too cold. This can cause a number of problems. When the nutrient solution is too cold (below 60°F) it will shock your plants and slow down the metabolic processes within the plant. This can stunt the growth of your plants.

There are a few ways of dealing with reservoirs that are too cold. Cold reservoirs are more often than not caused by plants being grown in basements during cold winter months. You can often remedy this by simply keeping the reservoir elevated off of the cold floor. A lot of heat can be transferred between the floor and the reservoir. If this doesn’t solve the low temperature problem, utilizing an aquarium heater is the next solution. They can be purchased at aquarium supply stores or many hydroponic retailers. They can be set to maintain the ideal nutrient solution temperature during the colder months of the year.

Problem: Nutrient Reservoir is too Warm

Solution: It is far more common for the temperature of the nutrient solution in your reservoir to be too warm (above 75°F) than too cold. This is largely due to the lights used to garden indoors. High-intensity discharge lighting can give out great amounts of heat, especially if you are growing in a small, confined space such as a closet or spare bedroom.


It is important for the temperature of your nutrients to stay in the range of 60 to 75°F because if it exceeds this range, the oxygen levels in the water are significantly reduced and plants need plenty of oxygen to survive. Overly warm nutrient solution evaporates more quickly and can become too concentrated, which might end up burning plants. It can also lead to the production of harmful bacteria, fungi and root-born insects.

Exhausting the warm air with a high-powered fan can usually reduce the temperature of your grow space but there are other methods that can help keep your nutrient solution within the ideal temperature range. Keeping your reservoir outside of the growroom is one great way to keep it from getting too warm. This can be accomplished by using a more powerful submersible pump to move the water greater distances. Another way is to keep the reservoir covered with black and white plastic with the white side facing up to reflect the light away.


If these methods are not effective enough, you may want to consider implementing a reservoir chiller to maintain the ideal nutrient solution temperature. Reservoir chillers are like air conditioners for your reservoir.

They can be set for a certain temperature and will remove the excess heat from the solution. Reservoir chillers are not the least expensive methods for regulating temperature, but they are extremely effective and will reduce the need to crank the air conditioning in your growroom.

In conclusion

Following these guidelines will certainly help any gardener regulate and maintain the temperature of the nutrient solution in their reservoir. This will lead to healthy and strong plants and happy, carefree gardeners.


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Written by Matt LeBannister

Profile Picture of Matt LeBannister
Matt LeBannister developed a green thumb as a child, having been born into a family of experienced gardeners. During his career, he has managed a hydroponic retail store and represented leading companies at the Indoor Gardening Expos. Matt has been writing articles for Maximum Yield since 2007. His articles are published around the world.

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