Preventing Heat Damage
Hydroponics stores Halifax gives you tips on your grow room air control….So you’ve got the lighting right, you’ve got a good growing system and you’re using the best nutrients available. If you fail to provide adequate ventilation and air movement your plants will never give you their full potential. Grow room air control and ventilation is crucial! If you’re growing under HID lights then you know these produce a lot of heat. If you’re not venting this heat out of the room the heat buildup will damage your plants and reduce their yield. Ideal temps for your grow room are between 24c and 27c with lights on and 21c to 24c with lights off. If you draw air from outside the building in the summer months and you’re lights are on during the night then this might provide a little cooling. During the winter months it might be wise to draw air in from the basement or crawl space as the winter air might drive temperatures too low.
Poor ventilation, stale or stagnant air and improper air movement provide airborne pests such as fungus gnats or sciarid flies a suitable climate to infest your crop. By making sure you have constant air movement using oscillating fans or air circulators and by creating a clean and constant flow of CO2 laden fresh air using an extractor fan you will create a less hospitable environment for pests.
Plants growing in an enclosed environment require fresh air to grow properly. The CO2 content of normal externally sourced air is approximately 0.03% and your plants require CO2 in order to photosynthesize, create energy and grow. Because there is such a low percentage of atmospherically available CO2 within the room plants will quickly deplete the available CO2 unless you are constantly replacing the air in your grow room. As a general rule of thumb, you should make every possible effort to replace the air in your grow room at least 20 times per hour simply to maintain a reasonable air quality and sufficient level of CO2.
Inadequate ventilation usually creates high humidity. This can lead to a number of problems at different stages in your growth of your plants. Ideally, you want to maintain a humidity of around 60% RH (relative humidity) during vegetative growth (as your plants do not have a very large root system and you want water to be taken in through the leaves) and during flowering reduce this to around 40% RH. The main reason to reduce the humidity during flowering is rot. After spending months growing and tending your crop, the last thing you want to find come harvest day are rotting flowers or fruits. Very humid conditions provide a perfect environment for rot to begin. Adequate ventilation will prevent the humidity from going to high. High humidity will be less of a problem if you extract humid hot air from your grow room and replace it with fresh clean air.