How to Save Water in Greenhouse
Water is a crucial component in any type of agriculture. However, the availability of water supplies and pricing of water are slowly becoming limiting factors in many places around the world. This past summer, even European growers suffered from unprecedented shortages.
The issue of water conservation is now on many growers’ minds. The need to save water and reduce water usage is now a part of the horticulture and greenhouse sector.
Fortunately, saving greenhouse water is something most growers can achieve. One thing you can do to immediately save hundreds of gallons of water per day, for example, is install dehumidifiers for humidity control.
How to Save Greenhouse Water – Greenhouse Water Conservation Tips
There are many different actions you can take to improve your greenhouse water efficiency. So, before discussing how dehumidification can save water, let’s go over some simple water conservation techniques.
The most critical change you can make is to your irrigation systems and protocols. Irrigation water is by far the biggest water expense in a greenhouse. So, the way in which you water your plants can have a huge impact on water efficiency.
Drip Irrigation Systems are More Efficient
First, you should water slowly and straight to the soil, ensuring you water each plant with the same amount of water.
Of course, hand watering is out of the question in a commercial greenhouse. So, the best way to irrigate would be using drip irrigation. A drip system provides a steady stream of water which the plants can use as they need it. This is much more efficient than simply dumping full loads of water, which saturate the soil and quickly run-off.
Morning Watering Optimizes Water Usage
Another step you can take to optimize your greenhouse water is morning watering.
Plants are extremely active in the morning. As the sun comes up, radiation starts hitting the plants, and they open their stomata to absorb it. The opening of the stomata also releases water vapor, through transpiration. So, this is the best time to water, as your plants most need it, and use it most efficiently.
Watering greenhouse plants is an important part of your day-to-day operation. So, the more precise your watering systems are, the more water you’ll ultimately save.
Avoid Leaks in Drainage and Other Greenhouse Water Systems
There are many ways to improve the water efficiency of a greenhouse operation. The most important of which is avoiding leaks in the drainage system, as well as greenhouse irrigation system.
Losing water to leaks can lead to massive water loss, which serves absolutely no purpose. On the contrary, having free water in the greenhouse is a catalyst for some of the most common plant diseases, such as powdery mildew or botrytis.
Monitoring Your Greenhouse Water
Like many aspects of a greenhouse operation, the water system can’t be completely efficient without proper monitoring. Taking account of your water inputs and outputs can tell you a lot about what’s going on with your water. It can indicate leaks or other inefficiencies in the system which may go unnoticed otherwise.
Fortunately, tracking water in a greenhouse is relatively simple. The more closed your facility is, the easier it is to monitor effectively.
When it comes to water input, monitoring is straight forward and often appears on utility bills. The output is a bit more complicated, however it can still be done.
There are two main ways in which water “leaves” the system, especially if you water your crops according to the previous tips. First, is through drainage. Excess irrigation water run-off is collected through a drainage system. In most cases, it’s relatively simple to monitor the water collected through drainage.
The second way water exits the system is through evaporation. Plants transpire most of the water they take in. Some water also evaporates from the soil itself. This all amounts to moisture – water vapor in the air.
It may seem difficult to track this water, as it’s in gaseous form and is essentially part of the air. However, high humidity is problematic for the plants. It leads to slower plant growth and development and can also lead to fungal disease outbreaks.
So, most greenhouse growers work to reduce humidity. The most effective way to do so is by using dehumidifiers. Luckily, dehumidifiers also make it extremely simple to track water vapor, and understand exactly how much of it is in the greenhouse.
By adding up drainage water and the water that comes out of your dehumidifiers, you can account for close to 100% of the water in your greenhouse. If this figure is significantly lower than your irrigation water, you know there is a problem somewhere in the system, allowing you to address it.
Using Dehumidifiers to Collect Reusable Greenhouse Water
Of course, dehumidifiers don’t just make it simple to track outgoing moisture or water. They have their own valuable contribution to water efficiency, by extracting water from the air.
The most common dehumidification technology for greenhouses is based on condensation. Air from the greenhouse is run through the dehumidifier, cooled down, in order to turn the water vapor into liquid, and reheated and extracted back to the space.
The water dehumidifiers collect can amount to hundreds or even thousands of liters per day. DryGair DG-12, for example, extracts 45 liters of water per hour. A single unit can provide as much as 1,000 liters in a single day.
This is completely reusable water. You can install a collection tank and collect it for future use.
Of course, as it’s distilled, it can’t be used as drinking water. However, it can be used for various other purposes. Many growers mix this water with run-off irrigation water, in order to adjust and optimize the nutrient balance in the water before reusing it for irrigation or disposing of it in a safe way.
Furthermore, greenhouse operations don’t use water just for irrigation. There are many ways to use dehumidifier water, such as cleaning, maintenance, washing machines, etc.
Collecting reusable from your dehumidification system may not cover all of your water needs. But it will allow you to turn off the taps for many of your day-to-day needs.
At the end of the day, water conservation can’t be complete with one action. It’s an accumulation of various ways to conserve water. With the right mindset, you can save a lot of water in your greenhouse operation, reducing costs, and improving your environmental footprint.
For more information on dehumidification, or a free consultation for your facility, contact us.
