Ideal Water Temperature for Hydroponics

• Published 04.14.22

As a hydroponic grower, you know that water temperature is important. But what is the ideal temperature? In this post, we will explain why water temperature is so important, what the ideal water temperature for hydroponics is, and several ways you can control water temperature.  

Hydroponics & Water Temp 

The ideal water temperature for hydroponics is important for a few reasons. The most obvious reason is that different plants prefer different temperatures. But the temperature of the water also affects the plant’s metabolism and nutrient uptake.  

When the water is too cold, it will slow down the plant’s metabolism and plants will absorb fewer nutrients. This can lead to several problems, including stunted plant growth, poor yields, and even death. On the other hand, if the water is too hot, it can cause the plant to wilt and can also lead to nutrient deficiencies.  

The ideal water temperature for hydroponics is somewhere in the middle, where the plant can thrive and reach its maximum potential. So, as you can see, maintaining the ideal water temperature for hydroponics is crucial for the success of your grow.  

Ideal Water Temperature for Hydroponics: Between 65-80°F (With Exceptions) 

The ideal water temperature for hydroponics will depend on the type of plants you are growing. Most plants generally prefer a water temperature between 65-80 degrees Fahrenheit.  

Of course, there are always exceptions to the rule. For example, some plants like cucumbers and tomatoes prefer a water temperature on the cooler side, around 60 degrees Fahrenheit. While other plants, like peppers and eggplants, prefer a warmer water temperature, around 75 degrees Fahrenheit.  

So, as a grower, it is important to research the ideal water temperature for your specific plants. You can find this information in most gardening books or online.  

Oxygen and Water Temperature 

The temperature of the water affects how much dissolved oxygen it can hold. Warmer water will push dissolved oxygen out of the water. Thus, a lack of dissolved oxygen can be a big problem in deep water culture systems, where the plant’s roots are always submerged in the hydroponic reservoir. The hotter the water gets, the less dissolved oxygen it will hold.  

Therefore, it is important to keep the water temperature in your hydroponic system within a certain range. If the water gets too hot, it can cause a lack of dissolved oxygen, and this can be harmful to the plant.  

Moreover, when the water temperature increases by 6°F (3.3°C), the dissolved oxygen levels in the water drop by 3 mg/L. 

Root Systems and Water Temperature 

Plant roots are also very sensitive to water temperature. If the water is too cold, it can damage the roots and lead to root rot. On the other hand, if the water is too hot, it can cause the roots to dry out and die.  

Furthermore, roots have developed to thrive beneath the surface where they are shielded from light and kept cool. For the roots in a hydroponic system to be healthy, you must replicate as much of this environment as possible. 

Therefore, it’s important to remember that root development may be stunted if the hydroponic reservoir temperatures fall anywhere below 55 degrees Fahrenheit. If the temperature falls below a certain level, most plants will stop taking in nutrients, and they won’t be able to produce new growth. 

Regulating Hydroponic Water Temperature 

No matter what type of plants you are growing, it is important to maintain the ideal water temperature. There are a few different ways that you can do this, including using a heater, chiller, or thermostat. By regulating the water temperature and water quality, you will ensure that your plants are getting the ideal growing conditions and will be healthy and productive.  

Raising Hydroponic Water Temp with Hydroponic Heaters 

If the water temperature in your hydroponic system is too cold, you can use a heater to raise the temperature. There are a few different types of heaters that you can use, including aquarium heaters and submersible pond heaters.  

Aquarium heaters are the most popular type of heater for hydroponics. They are easy to use and can be placed in the reservoir or sump. Submersible pond heaters are also a good option and can be used in larger systems.  

Lowering Hydroponic Water Temp with Hydroponic Water Chillers 

If the water temperature in your system is too hot, you can use a hydroponic water chiller to cool it down. Hydroponic chillers are like air conditioners and use a refrigerant to cool the water.  

Essentially, the refrigeration system circulates heated water from your nutrient reservoir over cooling coils. The chilled water is then returned to the reservoir, while the heat that was removed from the water goes back into the surrounding air. 

However, a hydroponic chiller is more expensive than a heater and is typically only used in larger systems. They are also more difficult to install and maintain.  

Maintaining Steady Hydroponic Water Temp with Hydroponic Thermostats 

Another option for regulating the water temperature is to use a thermostat. With a thermostat, you can set a desired temperature, which the thermostat maintains. This is a good option for growers who want to keep the water temperature within a specific range.  

Thermostats for hydroponics can be analog or digital. Analog thermostats are the most common type and are easy to use. Digital thermostats provide more accurate control over the water temperature and are ideal for larger systems.  

By using one of these methods, you can ensure that you are providing your plants with the ideal water temperature for hydroponics. This will help them to grow healthy and produce high yields. 

Keep Your Garden Growing 

As you can see, keeping your hydroponic water temperature within certain parameters is crucial for the health and success of your plants. By using one of the methods we’ve outlined, or by investing in a quality hydroponic temperature control system, you can rest assured that your plants will be happy and productive.