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Checking Your Vitals – Nutrient Temperature With Hydro Harvest

Summer temperatures can be both friend and foe to growers. Properly monitored and harnessed, the natural heat of the season can have a profound effect on the development and productivity of your plants.

But when temps get out of control the consequences can be disastrous. Indoor climate crises can happen so easily, especially at a time of year when we’d all rather be off enjoying the light of day, appreciating outdoor organic lifeforms in all their finery.

The good news is that temperature monitoring makes climate problems predictable and preventable. What’s more, the solutions can help you get bigger, better plants, more quickly, and at a dramatically reduced cost.

The two key areas for growers to monitor are room temps and nutrient temps. Because you can experience room temperature it often gets more of a look-in than that of your nutrients (unless you are incredibly unwise you’ll not want to experience your plants food and water first hand). You feel the room temp, you get it, you certainly need to hang a number on it and regulate accordingly, but you’ll always notice a hot or cold climate.

What sometimes gets overlooked is nutrient temperature. That oversight is a problem as there’s a strong argument that, for your plants, the most immediate potential shock is that of fluctuations in nutrient temperature. Getting nutrient temperature wrong can have an extreme effects.

Oxygen availability in your nutrient solution and the rate of nutrient absorption hinge on your feeds being at an optimum operating temperature. At a certain point temperature starts to affect nutrient concentration which can burn your plants. Anything above 26 degrees Celsius is a problem.


Finding out the heat of your nutrient solution is simple. Devices such as the Bluelab Combo Meter allows you to dip in, get a quick, accurate, clear grasp of your reservoir temperature, and act as necessary.

The Bluelab Guardian goes a step further and acts as a permanent monitoring fixture that reads, records, and reports temperatures without your physical presence. The latest models of the Guardian even include optional WiFi communication with your mobile device via the Bluelab app. These monitors are a bit of an investment. But consider that their functionality also includes EC and pH monitoring which allows you to understand the impact of temperature, and temperature correction, on your nutrient concentration.

Correcting a high temperature in your reservoir requires a little experimentation although the steps you can take are, in and of themselves, relatively straightforward.


If you’ve got an overly warm reservoir then you may well want to reduce your overall room temperature anyway by means of extra ventilation. It’s worth seeing how checks or upgrades to your intake and extraction can lower nutrient temperature before making your next move.

Reservoir position

Simply move your reservoir outside of your grow room. This means you can isolate and control reservoir temperature whilst allowing your plants to enjoy their own climate. The issue of how to maintain supply pressure to your watering system is easily resolved by means of a submersible pump.

Reservoir wrapping

Applying a reflective wrap to the outside of your reservoir is an easy and inexpensive way to maintain a steady temperature.

Reflective reservoirs

Want to deflect heat and light away from your reservoir without the fuss of wrapping? For an off-the-peg solution FlexiTank offer Pro models of their fully collapsible reservoirs in 100, 225, and 400L sizes. These feature a tough white skin that keeps your nutrient solution stable and effective even in bright, hot environments.

Reservoir chilling

For maximum adjustability and near-immediate effect deploy a reservoir chiller. These devices go straight to work, rectifying fluctuations in nutrient temperature. They are more of a quick-fix and they aren’t the most efficient if used to fight against an overheating setup, but chillers will get your supply back on an even keel.