When gardening hydroponics and aeroponics systems it is absolutely imperative that you control the temperature of your garden environment. Temperatures over 85 F create a stressful environment for your plants. This can cause a reduction in yield, and quality. Also, insects such as spider mites reproduce 2-3 times faster in hot, dry environments. In addition, stressed plants are prone to root, and foliar disease. A few things that you can do to control the temperature of your hydro garden, and reduce plant stress are cool your lighting, air condition your garden environment, and/or give your plants additives that help them fight disease.
There are two basic ways to cool your hydroponic lights. Air cooling your lights is the simplest. To do this attach ducting to the vents on both ends of your light hood. Connect one duct to an air intake port, and connect the other duct to an exhaust fan that is connected to an exhaust port. Your lights need to have a lens. This way your lights are sealed off from your growing environment. This method will reduce the temperature of your hydro garden by 5-10 F. Water cooled lighting systems are also available. During the summer air cooled lighting may not be as effective. Water cooled lights work all year. However, water cooling is much more expensive, and complicated.
Using an air conditioner is another way to reduce the temperature in your garden environment. This method can be used in conjunction with light cooling. The recommended ratio, when using air conditioners to control the temperature in your garden environment, is 4500 btu/1000watt light. For best results, the air conditioner should be placed in the window of a separate room. Set the temperature on the ac unit to a desired temperature. To cool your garden space duct the cool air, from the spare room, into your grow room, and duct the warm air, from your grow space, into the spare room. This way, your spare room acts as a lung for your garden space, treating the air that goes in, and retreating the air that comes out. When using this method the spare room should be larger than the grow space. Because this method is essentially a closed system, very little outside air is being introduced into the grow environment. Therefore, CO2 supplementation is required. There are many CO2 systems available for this purpose. If a spare room is not available, duct the air conditioner directly into the garden room.
Another thing that can be done to reduce the stress in the garden environment is to strengthen plants against disease, and a warm climate. To do this, foliar spray, and apply at the roots a beneficial fungi, and, a potassium silicate additive. Potassium helps to regulate the openings on the under-sides of the plants leaves. These openings control the water loss from the plant. Silicate coats plant cells, making them more resistant to disease, and water loss.
If the edges of plant leaves are curling upwards this means the grow room is too hot, and the plants are stressed. To control the temperature of your garden environment, and reduce the stress of your plants cool your lights, air-condition your grow space, and strengthen your plants. The most important thing is to enjoy gardening hydroponics, and aeroponics systems, and live to grow.