Keeping Your Greenhouse Cool
While one of the main purposes of a greenhouse is to keep your plants warm, excess heat will do far more harm than good. It is important to make sure that your greenhouse does not overheat. If it is too hot your plants will show signs of stress. If plants appear to be wilted despite watering or are failing to produce fruit, heat may be your problem.
In order to first diagnose the problem, you may want to do a little bit of research first to find out the optimal growing temperature for your favorite plants. By using a min/max thermometer, you can find out exactly how hot your greenhouse becomes during the day. If it looks like the greenhouse is too hot for your plants to thrive, it is time to address cooling in your greenhouse.
One of the simplest ways to prevent overheating is the use of a shade cloth. This will help to block out some of the sun, which is the primary source of the heat. Shade cloths are most typically used from around June to August (depending on the climate), when there is plenty of sun for your plants.
Ventilation is important in a greenhouse for many reasons, but during hot weather it is especially crucial. Circulation fans will help to keep the greenhouse evenly warmed, while exhaust fans will push out stale air so that fresh air can move in. Proper ventilation also prevents pest infestations, which can be a problem when plants are stressed.In some areas of the United States, the only way to sufficiently cool a greenhouse will involve the use of an evaporative cooler. These small units will allow heat to leave the greenhouse, keeping your plants cool. If you live in a particularly warm climate or plan to actively grow during the summer within your greenhouse, this is a wise investment.