Coming up to summer, you will quickly find your indoor growing temperatures exceeding the friendly range for plants at around 25 degrees Celsius. There are a number of things you can do to continue to grow through the summer, read on to find out how.
CHANGE YOUR VENTILATION
Intake air from under the house or from another shaded area – colder air in means a cooler growing environment. If you can intake air from an air conditioned room, this is even better. Often growers use an air conditioner actually inside their growing area, so there is no wasted cooling capacity
INCREASE VENTILATION FLOW
The more air that is flowing through the room refreshes the CO2 for plants and removes the excessive heat and humidity straight away. If you can increase you room air turnover to once every 1 or 2 minutes, the plants will respond with better growth, and your temperature is likely to come down. If you can keep the temperature high during the night cycle, it can have the effect of reducing the “stretch” in plants – that is the amount they grow vertically instead of out sideways.
CHECK YOUR EQUIPMENT ARRANGEMENT
Keep your ballasts and water reservoir outside of the growing room, to make sure they are kept cool. Electrical equipment all gives off heat, so keeping it away from the plants is best. The water reservoir should be kept in the range of 18C to 21C for the plants roots, and you can add ice to the water or use a water chiller to keep the water cool in recirculating hydroponics systems.
CHANGE YOUR LIGHTING
LED grow lights are a lot cooler that HPS and MH grow lights – they use less power too. Just be aware some models use fans to cool themselves, and these fans may blow air down into the grow area, also making it hot for plants.
Cool tubes take the hot air away from your lamps instantly, but reduce the life of your lamps and also slightly reduce their effectiveness due to the glass between the lamps and the plants.
Running your lighting during the night, when temperatures are slightly cooler, can also help to keep the heat at bay. Ensure to keep the area completely dark, otherwise the plants will be stressed.
LETTING THE TEMPERATURE GO UP AND USE CO2
CO2 will bring the time to harvest down 20% or 30%, with the benefit of letting the grow run at temperatures of around 30 degrees and above. The ventilation method is different – using pure CO2 as the growing air for the plants doesn’t need an exhaust fan at all, however many choose just to boost the CO2 in the room with TNB CO2 bottles or CO2 Enricha during lights-on, and running a vent fan very slowly. Then run the fans as per normal through the night when CO2 isn’t required.
Using a dehumidifier will reduce the stress on the plants from excess humidity and speed up transpiration – also a great idea if you are running a closed room with CO2.