The Current Water Crisis and the Need for Alternative Farming Solutions
It’s no secret that drought is a significant problem in the Western US, and the problem is only getting worse. As of this writing, the US Drought Monitor map shows several large regions in extreme or exceptional drought conditions, and nearly all of several western states are in severe drought or worse. Since some of the areas that are worst affected are also our most productive areas for food production, this problem could have far reaching effects on the country’s food supply. We must look for alternative growing methods that use far less water to produce healthy, fresh crops.
How Much Water Does a Traditional Farm Use?
Agriculture is one of the world’s top consumers of water. It accounts for an estimated 70% of all water use annually. And out of that huge amount of water consumption, about 40% is lost or wasted due to poor irrigation systems, evaporation, and general poor management. Clearly, this isn’t a level of waste we can continue to support, but how can it be fixed?
There are several current concepts for conserving water in the agricultural process, and the truth is it will likely take many of these ideas working in conjunction to replace the antiquated and wasteful irrigation processes of the past. One of the most exciting methods being proposed is hydroponic vertical farming. But how can a system that replaces soil with water save water? Read on to find out.
Hydroponic Vertical Farming Water Usage
Hydroponic vertical farms work like this:
Plants are grown in towers or trays, stacked vertically, and often indoors.
Rather than being rooted in soil, these plants’ roots are suspended in water.
The nutrients needed for plant health are added to the water, allowing plants to absorb them more efficiently than in traditional soil-based growing methods.
The water in the system is recycled repeatedly, allowing the most efficient systems to boast 98% less water use than traditional farming methods.
Does Hydroponics Save Water?
Yes, you read that right. These systems can function with only 2% of the water use that other growing methods might use. But that’s a hard concept to understand in the abstract. So let’s talk numbers. We’ll use spinach as an example since that’s one of the most common crops grown on a hydroponic farm.
On a traditional farm, producing one pound of spinach takes about 35 gallons of water. This is considered a relatively low water consumption rate, but hydroponics can improve it. If your hydroponic system can grow that same pound of spinach with 98% less water use, you’re looking at 0.7 gallons of water used.
Compare 35 gallons of water used versus 0.7 gallons, and you can see with such numbers, it’s easy to see just how much water can be saved. But how do these farms manage these drastic savings in water?
How Do Vertical Farms Use Less Water?
To understand how vertical farms use less water, you have first to understand where a lot of the water goes on traditional farms. You probably learned as a child that plants need water to grow. While this is certainly true, that’s not the bulk of the water used in crop irrigation. Here are a few of the other places that the water goes:
Evaporation – water goes back into the air
Runoff – water ends up in bodies of water or drainage systems
Lost into the ground – water sinks in too deeply for roots to reach
Other potential losses, such as leaky irrigation systems, may end up losing water between the source and the crops, but these are the main culprits. The good news is that a properly designed vertical farm can eliminate all of these potential losses.
First, no water can be lost in the ground because there is no ground in a hydroponic growing system. Likewise, there is no concern about runoff because the water is intentionally directed through channels designed to reach the plants and then return to the storage tank. Even evaporation isn’t a significant concern when you contain your system within a greenhouse and then use dehumidifiers or similar technologies to remove excess water from the air and return it to the irrigation system.
Other Benefits of Vertical Farming
Of course, vertical farming offers many benefits beyond its incredibly efficient water use. Among these are saving space, no soil degradation, urban farming, and the ability to grow crops out-of-season.
Vertical Farms Save Space
It’s a simple idea to imagine that when you stack crops on top of one another rather than planting them along the ground, you’ll end up needing far less space to grow. But just how much space does vertical farming save? When you think about the idea, you may not be surprised to learn that vertical farms can take up about 99% less land than their traditional counterparts.
Why is this important? It makes it far easier to fit farms into urban areas. These farms can produce up to 500 tons of leafy greens yearly in as little as an acre and a half. That’s less space than many big-box stores and a size that can often fit into even the most densely populated areas. Creative growers have even placed vertical farms on rooftops and inside office buildings.
Vertical Farms Save Soil
Water isn’t the only major problem in farming today. Soil degradation is another serious concern that is becoming an increasingly dire situation. The GEF (Global Environment Facility) estimates that a quarter of the world’s topsoil is already gone, and we continue to lose about 24 billion tons of fertile soil annually. This could mean a 95% loss by the year 2050.
Fortunately, vertical hydroponic farms offer a way to grow fresh, healthy foods with no need for soil (fertile or otherwise) at all. This means that not only are vertical farms not contributing to the problem, but they can also help solve it by taking away some of the strain currently causing the problem.
Vertical Farms and Seasonality
The third benefit of vertical farming is that indoor vertical farms can grow their crops regardless of season or climate. So we can grow fresh, delicious greens year-round, even in some of the world’s harshest climates. No more shipping your favorite salad ingredients from the other hemisphere in the dead of winter. Instead, you can have fresh, locally grown greens year-round with around a dozen harvests annually.
Potential Downsides
Of course, there are a few potential downsides to vertical farming that will prevent the practice from completely replacing wasteful irrigation practices themselves. We would be remiss not to address crop selection and energy use.
Vertical Farming Energy Use
The biggest complaint surrounding vertical farms is the excessive use of energy that some of these systems require. Some farms are set up using fossil fuel-powered grow lights as their primary source of light energy. In systems where crops are grown in trays stacked one on the other, these grow lights may be the only option since each level of plant shades the one below.
Fortunately, there are other options available. Some vertical farms grow their plants in towers rather than trays. These towers are housed inside glass greenhouses and spaced far enough apart for sunlight to penetrate all levels of crops. Systems like Eden Green Technology’s hydroponic grow houses use 90% less light energy than other vertical farming options, leading to a far more sustainable farm.
Vertical Farming Doesn’t Work for All Crops
One reason hydroponic vertical farming will never fully replace traditional farming methods is that some crops simply don’t grow in such a system, and plenty of others aren’t ideal for such a method. Leafy greens, herbs, and microgreens are the best crops for hydroponic growth. Other options include strawberries, tomatoes, and peppers, though these crops are less common in hydroponic growing. Underground crops like potatoes, carrots, garlic, and onions are not suited for such systems and do better when planted in soil.
While vertical farming is one piece of the solution to our current water crisis, it cannot be the only one. Instead, we need to use this growing method with other agricultural technologies to create a more sustainable farming future and a more stable food supply.