Are you turning off your grow tent for the summer? We'll advise you on how to avoid it!

Although Central Europe is no Sahara, many indoor growers are forced to switch off their grow room during the hot summer months. Plants grown indoors thrive best at room temperatures, and although they can withstand more extreme heat for a short time, this has a significant impact on their health and yield. In the end, it may not even be worth switching on the equipment. But how should you set up your grow room so that you can cultivate all year round?

Replace outdated discharge lamps with LED lighting

If you are still using discharge lamps (HPS, MH), summer is the ideal time to switch to LED grow lights. Discharge lamps emit a lot of heat and convert up to 70% of the energy they consume into infrared radiation, which directly heats the growing space and does nothing to support plant growth. LED luminaires have lower power consumption and produce minimal heat, which will significantly reduce the temperature in the growing space. In addition, you will save on electricity bills, because compared with discharge lamps, LED diodes convert much more of the supplied energy into photosynthetically effective radiation in the PAR spectrum.

Pro tip: If you light during the day and are struggling with high temperatures inside the growing space, try lighting your plants at night, when it is cooler.

Improve ventilation and air circulation in the growing space

It is obvious that the better and faster you manage to remove heated air from the growing space, the cooler it will be inside. Before you start buying new equipment, however, first check what you already have. A common cause of ventilation problems is clogged carbon filters and fans, or leaking ducting and joints. If that does not help, try the following:

• Increase extract performance: Check whether your fan can handle the increased load. It may be time for a more powerful model.
• Maintain negative pressure in the grow box: Ideally, the extract performance should create slight negative pressure in the grow tent. You can tell this by the “sucked in” walls of the grow box.
• Add circulation fans: Circulation fans not only help plants develop strong stems, but also prevent hot air from building up in one place.

You may also be interested in: Where and how to position fans correctly in the grow room

Air conditioning and cooling

If you have tried all of the above advice and still need to reduce the temperature in the grow box a little, it is time to use air conditioning. Air conditioning units are relatively expensive to run, so use them efficiently. Always vent the warm air from the air conditioning unit outside or into another room. Use timers and thermostats so that the air conditioning runs only when it is absolutely necessary.

CO₂ supplementation

Although for most growers the best approach is to keep the temperatures in the grow box at optimal levels, under certain circumstances they can be an advantage. Specifically, this refers to supplementing the atmosphere in the growing space with carbon dioxide. Plants use CO₂ during photosynthesis, during which they absorb light and convert it into energy in the form of glucose. Higher concentrations of carbon dioxide allow plants to carry out photosynthesis at higher temperatures. Under normal conditions, the air contains around 400 ppm of CO₂, which allows plants to carry out photosynthesis efficiently at temperatures between 25 and 30 °C. It has been found that if the CO₂ content is increased to 1935, this temperature can rise to as much as 36 °C.

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