Evaluate Your Greenhouse Cooling Strategy
While plants can cool themselves to some degree, during the summer months they’ll need help to reduce heat stress, avoid injury to their delicate tissues, and maximize growth. Therefore, it’s extremely important to both reduce temperatures in the greenhouse and keep the air circulating using an effective greenhouse cooling strategy.
You may already have some kind of shade cloth or covering in place, but supplemental cooling methods are also needed now. Let’s take a look at the most common options.
This process of greenhouse cooling basically involves letting out hot, moist air so that cooler, drier air can get inside. There are various ways to do this, including natural means — that is, with passive greenhouse ventilation including: wall vents, louvered windows, and roof vents. For optimum effectiveness, make sure doors are closed so they don’t interfere with ventilation flow.
Circulation fans are also effective at moving the air through, and tend to do so more quickly than natural processes. Depending on the size of your greenhouse, you can use greenhouse fans that are either inset in walls, attached to ceilings or walls, or free-standing. We offer a wide choice of circulation fans of all kinds to suit your space and budget.
A word of caution: don’t over-ventilate, especially in hot, dry climates. Unless you also use an active humidification system, this can seriously dry out the tissues of your plants.
Evaporative cooling systems humidify the air as they cool, and represent a very helpful (and often necessary) supplement to ventilation methods. Many evaporative cooling systems are positive pressure types, involving a through-wall cooler that introduces cool, moist air while pushing hot, dry air out the existing exhaust system. However, another popular, commonly-used evaporative cooling method is the fan and pad system. In this case, air is drawn in through water-soaked pads, resulting in cooler air at a high humidity. Both greenhouse cooling methods are essential if you expect to lower the temperature inside your greenhouse beyond what the outside temperature might be.
To avoid problems with excess humidity and wetting of foliage overnight, which can encourage fungal growth, be sure to stop evaporative cooling early enough in the day for the excess humidity to disperse.
Additional Greenhouse Cooling Methods
You can also use various low-level water delivery systems to supplement both evaporative cooling systems and greenhouse ventilation. Foggers, misters and sprinklers can all be helpful, especially when used in combination with specialized greenhouse fans. They work on a similar concept to an evaporative cooling system, and as with those systems, be sure to turn them off early enough in the day for things to dry out a bit before nightfall.
Greenhouse Ventilation and Cooling Controls
Automated controls can make greenhouse cooling hands free and much easier — they’re vital if you ever have to spend a couple of days away from the greenhouse. We offer both standard and digital thermostats, of course, but our controls can also help you control or replenish humidity, moderate circulation or exhaust fan activity, or even control temperatures by varying vent fan speeds.
However you decide to go about it, greenhouse cooling is absolutely critical during the summer months. This is true in all but the mildest climates. Luckily, we have the products and expertise you need to get the job done, and the necessary systems to control them. Take the proper precautions, and you can be enjoying bountiful harvests and beauteous flowers all summer long!