Greenhouse Controls
Environmental control in your new greenhouse. In order to manipulate the environment of your greenhouse there are three basic controls to be aware of: Temperature, Humidity, and Water. Luckily all of these can be maintained auto– or semi-automatically.

Posted Tuesday, January 24, 2006

In order to manipulate the environment of your greenhouse there are three basic controls to be aware of: Temperature, Humidity, and Water. Luckily all of these can be maintained auto– or semi-automatically.

For temperature you’ll need a greenhouse thermostat. In fact it is debatably the most important of all greenhouse accessories. Thermostats will keep room temperature at optimal levels if installed correctly. They work in the same way as an in-house thermostat. Whether you grow in harsh weather conditions, or a natural paradise, it's still crucial to maintain constant temperatures. If the temperature ever falls below desired levels a thermostat switches on to heat the room again. You’ll find a great selection of thermostats available in gardening stores or online.

There are many kinds of thermostats on the market today and we recommend sticking with a name brand for quality and durability. For those growing everyday plants without a big budget, there are inexpensive thermostats that automatically keep the temperature between 70 and 78 degrees Fahrenheit. Research the needs of your plants before deciding upon which thermostat to use. For example: A sensitive plant may need a higher-end thermostat that can narrow the temperature range.

When installing a thermostat, it should be placed near the center of a greenhouse, as close to plant height as possible. A popular way to do this is to erect a piece of wood and then mount the thermostat onto it. It's important to have the thermostat shaded from direct sunlight; also, paint the wood white to prevent it from absorbing heat. Be sure to place the plank of wood in the middle of your greenhouse where it isn’t affected by walls which can lose heat.

Typically, growers have simple plants that require set temperatures. Keeping the temperature between 70-78 degrees Fahrenheit is usually enough to keep most plants healthy. For those who don’t want to spend a lot of money on expensive thermostats, there are several on the market which keep the room at this temperature, and retail for under $20.

A humidistat is an important way to control the humidity of your greenhouse kits or growing area. If you're unsure as to whether you need to worry about the humidity take some measurements. Find out the desired humidity range for your plants, then take several readings of the humidity in your growing area--try late at night, early in the morning, noon, and evening.

There are two main types of humidistat— there are simple humidistat and then more advanced ones that control both the high and low end of the humidity. Most plants don't require such rigid care; a regular humidistat can be used to raise the humidity when it drops too low. If high humidity is also a concern, then a total humidity controller is probably in order. A humidity controller should be easy to use--no more difficult than thermostats. Most come with a dial, and an on-off switch. Turn the dial to select the desired humidity, activate the power source, and you're set--most hook up to any kind of humidity-regulating device.

Many growers use an internet vendor to get a reliable source for their humidistat. In addition to increased selection, a recommended web vendor will offer the most competitive prices possible. For humidity you’ll need a product that keeps the air between 20 and 80 degrees Fahrenheit for plants to survive. For plants with special needs you can find products that will keep the humidity within a narrower range. Fortunately, there are automatic humidistats that can keep any room at comfortably humid levels.