There are many good reasons why hydroponic gardening is typically done indoors. The heightened control of an indoor or greenhouse environment is perfect for reaping all the benefits of hydroponic growing. The advantages of hydroponic gardening generally include faster growth rates and larger yields due to the plant’s increased accessibility to nutrients and oxygen (for the roots).

Although indoor environments make it easier to control many of the variables that affect the way a hydroponic system performs, many growers are also taking hydroponic gardening outdoors. In fact, with a few alterations, most outdoor hydroponic systems will offer growers many of the same benefits as an indoor environment. Outdoor hydroponic systems also provide a possible solution for poverty stricken nations, where food security is scarce due to a lack of resources.

Advantages of Outdoor Hydroponics vs. Traditional Agriculture

Outdoor hydroponics’ largest advantage over traditional agriculture is water usage. Traditional soil-based agriculture requires nearly 300,000 gallons of water per year per person supplied with food.

For nations without a reliable source of water, traditional agriculture is either extremely limited or impossible. Traditional agriculture also requires cleared land, which reduces animal habitats and, in turn, reduces animal populations. The use of herbicides, pesticides, and fertilizers in traditional methods contribute to the pollution of land, air, and water. Not to mention this eventually sterilizes the soil, rendering it stripped of sufficient nutrients.

Conversely, an outdoor hydroponic system only requires five to 10 per cent of the water used by traditional agriculture. In other words, the amount of food produced using 300,000 gallons of water in traditional agriculture can be obtained by using only 15,000 to 30,000 gallons of water in an outdoor hydroponic system. Outdoor hydroponic systems do not require the same land clearing or destructive use of herbicides, pesticides, or fertilizers. In fact, most outdoor hydroponic systems will recycle the water and fertilizers so they can be used repeatedly.

Outdoor hydroponic systems offer another advantage over traditional agriculture in that they can be customized to fit many different applications. Outdoor hydroponic systems can be hung, stacked, set up vertically or horizontally, or configured in just about any way to best meet the needs of the space and the crop being grown.

Disadvantages of Outdoor Hydroponics

Although there are many benefits to using outdoor hydroponic systems, there are also some disadvantages. The initial cost of equipment is a large shortcoming of outdoor hydroponics. This is especially true if it is a large system and/or if the system is going to be automated. The larger the hydroponic system, the higher the initial cost. An agriculturist who has a large garden space must consider how long it will take to recoup the initial expense of the hydroponic system.

Automating a hydroponic system adds extra cost. Expensive computer controllers, sensors, pumps, and other mechanical equipment must all be purchased, synchronized, and maintained to ensure a properly running hydroponic system. All this equipment quickly adds up. However, more automation requires less labor. This can reduce costs and increase the amount of time a horticulturist gets a return on his or her investment.

Another disadvantage of outdoor hydroponic systems is the inability to control nature. Unlike indoor hydroponic systems, horticulturists will not be able to control temperature, humidity, rain, etc. They will also not have control over lighting, since outdoor systems rely solely on the sun. Sunlight is superior to artificial lighting in many ways, but its intensity can cause problems over time for outdoor hydroponic systems.

Sunlight can cause damage to plastics and other hydroponic components that are not properly UV protected. Some hydroponic systems are more susceptible to damage caused by temperature fluctuations. Intense sunlight on reservoirs and plant modules can cause temperatures to rise and then exceed the desired temperature range for optimal growth. Modifications may have to be made to a typical hydroponic system to make the system operate as smoothly as possible in an outdoor environment.

As with traditional agriculture, regions with cold winters would not be able to grow crops year-round in an outdoor hydroponic system. Extending the growing season is one of the main reasons horticulturists choose to grow indoors or in a greenhouse.

Types of Hydroponic Systems Used Outdoors

Just about any type of hydroponic system can be used outdoors with success. That said, hydroponic systems in which the root mass is constantly submersed in water (deep water culture) are typically avoided due to the difficulty of controlling water temperature fluctuations. Top feed, flood and drain, and aeroponic systems are all commonly used with great success.

Growers will often modify these commonly used hydroponic systems when operating them outdoors. Lining the hydroponic system and reservoir with a reflective insulating material can help protect the roots from prolonged exposure to intense sunlight and/or temperature fluctuations.

Covering the hydroponic system will also help protect the plastic or other materials from being damaged by sunlight. Plants grown in an outdoor hydroponic system can grow extremely fast, which means they will take up more water and nutrients than when in an indoor environment.

Over the past ten years, three types of hydroponic systems have come into the forefront of outdoor hydroponics. Those systems are vertical hydroponic systems, aquaponic systems, and simplified hydroponics.

Vertical Systems

Vertical hydroponic systems are hydroponic systems that are set up vertically instead of horizontally. The biggest advantage of this type of system is maximization of floor space. Since the plants are set up in vertical rows, more plants can fit in a given garden area. This is the main reason why vertical hydroponic systems are utilized in rooftop gardens and in other gardens where space is limited. There are also many vertical hydroponic systems which can be integrated into urban planning and development. For example, constructing vertical hydroponic systems on the sides of buildings or other structures can be a way to produce food in densely populated areas.

Aquaponic Systems

Aquaponics is a hybrid of aquaculture (fish farming) and hydroponic gardening. Aquaponic systems use the waste produced by fish to feed the plants. Some of the most ancient “hydroponic” methods used to grow crops were essentially aquaponic outdoor hydroponic systems. The biggest advantage of outdoor aquaponic systems is the ability to produce two sources of food (fish and vegetables) from one system. Aquaponic systems also reduce the need for fertilization of the plants. In fact, in a perfectly functioning aquaponic system (with solar powered mechanical pumps), the only input would be the food for the fish.

Simplified Hydroponics

Simplified hydroponic systems are hydroponic systems being used by developing countries or in regions where access to power is impossible. Simplified hydroponics is soilless gardening without the use of mechanical equipment. In simplified hydroponic systems, the circulating or aerating of the system is done manually instead of with a mechanical pump.

The two most common types of simplified hydroponic systems in use today are flood and drain systems and floating bed-type systems. The flood and drain systems are hand-watered once or twice a day with nutrient-infused water. The run-off is collected and reused.

The floating beds are hand-aerated by stirring the water two or three times daily. The floating beds method is more susceptible to temperature fluctuations and would most likely be avoided in regions where dramatic temperature fluctuations naturally occur.

Simplified hydroponic systems offer many advantages to farmers or families in developing nations, including self-sufficiency, the ability to recycle nutrients, and reduced water usage. A simplified hydroponic system can provide about $300 worth of food for around $30 worth of nutrients. The produce grown in a simplified hydroponic system is likely to be consumed shortly after harvest, which means it will retain a higher vitamin content and will be more flavorful.

When managed correctly, a simplified hydroponic garden will provide food three to four times faster than traditional methods. Overall, simplified hydroponic gardens are a great solution for families or small communities in developing countries who seek self-sufficiency and increased access to fresh produce.

Hydroponic gardening’s role in agriculture is growing yearly. Although many outdoor agriculturists still have access to land, water, and nutrients, these resources are quickly diminishing. In terms of agriculture, outdoor hydroponic systems offer a real solution to many of the problems created by the depletion of our resources. Outdoor hydroponic systems also offer unique solutions to the problems facing urban areas and their inability to produce fruits and vegetables locally.

Don’t be surprised if, in the near future, architects include vertical rooftop systems or integrated hydroponic systems to typical building specifications. Finally, outdoor hydroponic systems are currently the best solution we have to combat many of the hunger issues facing under-developed nations.

Simplified hydroponic systems could be the difference between self-sufficiency and starvation for many families and small communities. When you examine the advantages of hydroponic gardening combined with the need for the human race to take serious steps in reducing our depletion of resources, there is no doubt that outdoor hydroponic systems will be a staple in the future of agriculture.