What's the best temperature for optimal plant growth?

The question of what temperature to keep a grow area is a good one. It's not an easy answer, but it's something that growers think about a lot. We often talk about the ‘threefold cord’ of temperature, humidity and pH value as the fundamental way to support plants and get them to thrive. So where you want to set your thermostat for hydroponic plants?

The answer is a little bit more nuanced than giving a simple set of parameters. It depends on the type of plants that you are growing, the space you are in, and other factors. But here are some of the basics.

Above the Plant Pot

Lots of growers like to keep the actual plant structures in the grow area at just slightly over room temperature. That means anywhere from 75-78°F.

This temperature makes many types of plants comfortable, and keeps them from experiencing the negative effects of either type of temperature extremes.

Reservoir Water

When it comes to the water that delivers nutrients to plants, the equation is a little bit different.

Here, many growers advocate for dramatically lower temperatures, lower than room temperature, and down to a range of around 50-60°F.

Why? There's some specific science behind this. One of the basic ideas is that water at a lower temperature has more oxygenation -- that you can tie a rising temperature to lower parts per million for oxygen. Then you look at how plants use oxygen, and how oxygen works in the water used for irrigation.

Simply put, in warmer water, it’s easier for other things to grow -- certain kinds of bacteria that can be harmful to plants. Most growers have probably heard of pythium, a bacteria that can really devastate crop cycles. Experienced growers understand that having room temperature or heated water in a grow system can invite these kinds of bacteria into the space.

The problem here is that in most cases, it requires specific effort to keep water at a lower temperature. Because of the lights and high-powered gear running in a grow space, water often wants to be warmer than the grower’s ideal range. This might require the use of water chillers or other equipment to keep the water cooler to protect plants.

For more tips on how to do hydroponics the right way, take a look at Dealzer’s website and browse our thousands of pieces of equipment and accessories for successful hydroponic growing.