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Water-Based Growing Systems – Alternatives To Soil Gardening


Gardening without soil

Due to concerns about pesticides and unsustainable growing methods, many people have decided to grow their own veggies. In an effort to conserve water, space, energy, and materials, a variety of soilless, water-based systems have evolved:

These systems all have impressive yields, lower water needs, better environmental control, and efficient use of space. 

Choosing which water-based gardening system to use will depend on your harvest goals, space, and resources. These systems require supplemental nutrition and carefully-controlled environments, meaning you will spend more time and energy maintaining them. Research your options carefully before building a system.

Soilless gardening systems are fun hobbies, but they can be expensive and time-consuming. Whatever system you choose, start small and test the waters. It’s easy to add on to a system if it works for you, but it can be expensive to start over if it doesn’t.

Planning

Before you build a system, decide on your production goals. Determine how many people you want to feed, how often, and what foods you want to grow. 

In general, the more people you want to feed, the less variety of plants you will grow.

For example, if you want to feed a family of four, you will want to grow a wide variety of plants that can supply different fruits and veggies on a regular basis. However, if you want to sell produce at the local farmer’s market, you will probably focus on 2-3 crops on a larger scale. 

Many systems with lower yields support a wider variety of plants. Media-filled aquaponic beds grow at roughly the same rate as traditional soil beds. However, they support the widest variety of plants among aquaponic systems. On the other hand, deep water channel aquaponics shows impressive yields above traditional soil beds, but it can only support leafy greens, herbs, and small vegetables.

Once you decide on your harvest goals, it’s time to decide on a location.

Any outdoor space can be converted to a growing space. Systems can be built to take advantage of vertical space or horizontal space. Pots or pipes can be hung from a support structure or laid on the ground. As long as there is a nearby water source, almost any outdoor area can be structured for growing.

Indoor spaces are a little trickier. Windows can provide some light, but most indoor systems will need supplemental lighting and ventilation. It is easier to control temperature, insects, and moisture levels on indoor systems, but diseases spread quickly in confined areas.

Any space you choose should be sturdy, easy to access, and able to handle moisture. 

Once you have a location, compare your available growing space to your desired harvest size. A 4’x4’ plot won’t feed the neighborhood, and a 40’x40’ plot will produce much more than a small family can use. Make sure your harvest goals line up with your growing space, and remember you can set up more than one system if you have a variety of available locations.

If you have a small space, but your goal is to sell your product, choose one crop and customize your system to fit the nutritional and light requirements. An easy, small-space income-generating crop is fresh herbs. Restaurants love purchasing fresh, local herbs, and they are easy to grow in tight places. 

Outline your goals, crop preferences, space, and location details on a sheet of paper. Then, use that information to narrow down which system will fit your needs.

Hydroponics

water-based growing systems like hydroponics offer solutions to harvesting without soil.

Hydroponics is the foundation of water-based growing systems. Hydroponics is the process of growing plants in a soilless growing media (or no media) with a nutrient solution (source).

Most hydroponic systems are closed, which means water is recirculated through the system to minimize additional water input. The water is tested periodically, and amended with fertilizer to maintain nitrogen, phosphorus, potassium, and other nutrient levels. Temperature and pH are also tracked, and they must stay within a small range to maintain plant health and prevent stress.

The major benefit of hydroponic systems is the ability to provide a customized nutrient profile to specific plants at specific times. This helps to increase yield, and can make it possible to grow some plants that would be hard to grow in local soil.

The major drawback of hydroponic systems is the constant maintenance of nutrients, temperature, pH, and water levels. Imbalances can quickly lead to insect infestations, diseases, and the loss of an entire crop.

Learn to grow vegetables and herbs without the fuss of weeds by using hydroponics. Follow a simple, easy to understand approach Click Here to learn moreOpens in a new tab..

Best for/Worst for

Hydroponics offers a wide range of applications for a wide range of growing goals. However, it’s not the right system for everyone. 

Hydroponics will work well for someone who wants to grow large amounts of leafy greens for sale, or a small, supplemental garden for their family. 

Hydroponics will not work well for someone who wants to grow large amounts of fruiting vegetables (tomatoes, peppers, cucumbers, etc.) without investing in extensive environmental controls.

There are two major categories of hydroponic systems, and many variations and circulation methods:

Deepwater culture system (DWC)

This system is easy to build, and easy to maintain. It has a simple design that circulates water through a grow bed with plants suspended above the water in a frame. Roots are only partially submerged in the water, which allows a balanced intake of oxygen and nutrients.

DWC systems are perfect for growing leafy greens and some herbs. However, they do not support fruiting plants or root vegetables. 

DWC is the most common major system, and most other hydroponic systems are a modified version of a deep water channel setup. Most commercial systems utilize the concept of DWC because it is easier to scale up, and the yields are higher.

Wick systems

Wick systems are a subtype of deep water culture. With this system, plants are grown in pots with a soilless media. Then, they are suspended over water with a wick extending from the media into the nutrient solution. The wick pulls water up into the roots of the plants, which may eventually grow down into the nutrient solution.

This system is easy to set up, but soilless media can be expensive. Wick systems are better for larger, fruiting plants that may be growing for a few months before harvest (peppers, cucumbers, tomatoes, etc.). 

Nutrient-film technique (NFT)

This system is a subtype of DWC. The major difference is that NFT systems use long rows of PVC pipe with holes cut in the top to hold plants, while DWC uses deeper grow beds and a frame. Water is constantly run through the pipes, but at a very low volume (hence, nutrient film). The tips of the roots are always submerged in the nutrient solution, but the rest are able to take in oxygen.

The main benefit of this system is that is incredibly easy to assemble, and it cuts a ton of time off the planting and harvesting process. However, like other media-less systems, it is only able to support leafy greens, some herbs, and other small vegetables.

Media-filled beds

This system is the one that most closely resembles a traditional garden plot. The soilless media provides a stable foundation for larger plants, and it also provides a place for beneficial bacteria to colonize, which helps the system run more sustainably.

Media-filled beds can either have water flowing through them constantly, or be setup for flood-and-drain circulation. Either method works well in these grow beds, which makes them the most versatile option and the best for beginning growers.

Drip systems

Drip hydroponics is a subtype of media-filled beds. Drip irrigation is a simple way to conserve water, and drip hydroponics maximizes conservation with precision. Pots with soilless growing media are suspended in a frame over a collection bin, and each pot is given a dedicated emitter.

A timer activates the irrigation system, which drips nutrient solution onto the roots of the plants. Any excess solution is collected in the bin, and recycled back into the reservoir. 

Drip systems are best for larger, fruiting plants that need more root space and longer growing times. It would work for leafy greens, but it would be an inefficient use of space.

Flood-and-drain 

This is not so much a hydroponic system as it is a method to circulate water through a hydroponic system. Deep water channels and media-filled beds can operate with either a flood-and-drain circulation plan, or a constant flow circulation plan.

With flood-and-drain, water floods the grow bed on a timed system. After a period of time, the bed is drained, and the water returns to a reservoir. The cycle repeats as often as necessary.

This system allows the roots to have time submerged in order to absorb nutrients, and it also allows the roots to have time in open air, which helps them absorb oxygen. Both are necessary for healthy plant function, and this method also results in less cases of root rot.

The major benefit to flood-and-drain systems is that the water temperature is easier to change, since it is sitting in a reservoir between cycles. The biggest drawback is that you must rely on a timer or manual siphon to circulate water each hour, or else you risk losing your entire crop.

Constant flow

This is the more common method used to circulate water through a hydroponic system. NFT, wick systems, and other setups with smaller volumes of water need to maintain a constant flow in order to keep the roots moist.

Constant flow is exactly what it sounds like; a constant flow of water. Instead of grow beds flooding and draining, a constant flow of water is circulated throughout the system. This can help maintain more even water temperatures, but it also makes it difficult to heat or cool larger volumes of water.

The major benefit to constant flow systems is that you don’t need timers or special siphons to flood and drain a system each hour. The major drawback is that roots are more susceptible to root rot.

All hydroponic systems can be used indoors or outdoors, but the risk of disease increases in enclosed spaces. Make sure any area you want to use for hydroponics has good air circulation to keep plants pest-free.

Aquaponics

Aquaponics uses fish waste to fertilize plants.

Aquaponics is a subtype of hydroponics. A fish tank acts as the source of fertilizer for the plants, and the plants act as a filter for the fish waste. 

Most aquaponic systems are closed, which means water will recirculate throughout the entire system. Bacteria within the system transforms the fish waste into basic nutrients for the plants, and the roots absorb the nutrients before the water circulates back through the fish tank. 

Using fish as a nutrient source can help a system become self-sustaining, but it also requires more work than a hydroponic system. Fish tend to like higher pH levels, cooler temperatures, and dark conditions. Plants like lower pH levels, warmer temperatures, and light conditions. This can make it difficult to keep the plants and fish happy.

The major benefit of aquaponic systems is that it provides a self-sustaining source of nutrients for the plant and a self-sustaining filter for the fish tank. It can also provide a protein source if the fish are harvested.

The major drawback of aquaponic systems is that you must maintain the pH, temperature, light, and water quality requirements for two different species with different preferences. The range for error is smaller, which can make an aquaponic system more time-consuming.

You can build a simple aquaponics system to grow your own organic food. Click here to learn moreOpens in a new tab..

Best for/Worst for

An aquaponic system is great for mid to large-scale growers who want a source of protein. The amount of time and energy it takes to maintain an aquaponic system is only worth doing if you want to harvest both the plants and the fish. 

An aquaponic system is not good for small-scale growers who don’t want to harvest the fish. Although small-scale systems work well, they are more difficult to maintain than a simple hydroponic system. If the main focus is the plant harvest, hydroponics will give you a larger margin of error, and require less time.

Systems

All hydroponic systems can be modified to add a fish tank, making them an aquaponic system. The major difference is that you must add a filter after the fish tank to remove solids, and a filter before the fish tank to remove excess ammonia and other waste.

The growing media in an aquaponic system serves a more important purpose than in a hydroponic system. The bacteria that transform fish waste into plant-soluble nutrients will colonize porous surfaces very quickly. The more growing media in an aquaponic system, the more surface area for the bacteria that work the transformational magic. 

This is why smaller hobby systems should always incorporate growing media; it helps the system sustain itself easier, and it gives you a larger margin of error. Larger systems can handle larger numbers of fish, and consequently smaller amounts of growing media.

Vermiponics

Vermiponics is another subtype of hydroponics, with the same basic concept as aquaponics. While aquaponics uses fish as the source of plant nutrition, vermiponics uses water filtered through a worm bin to cycle worm castings through a hydroponic grow bed.

The major benefit of vermiponics is that it can be scaled down to extremely small applications that are unsustainable with an aquaponic system. If you want to grow a few heads of lettuce above a fish tank, the plant roots and grow media may not be able to filter the fish waste, and one fish may not be able to supply the necessary nutrition. However, a worm bin has an ecosystem perfectly suited to these small-scale scenarios, and it is cheaper to feed worms because they eat table scraps.

The major drawback of vermiponics is that it can be difficult to plumb, and difficult to maintain large volumes of water in a large setup. Worm bins in a vermiponics system only filter water through the very bottom, as opposed to a large fish tank full of water. This is fine for small grow beds that use little water, but it can be difficult to filter the water necessary for large grow beds through multiple worm bins.

Best for/Worst for

Vermiponics is best for small, educational systems that can support a personal garden. Compared to an aquaponic system of the same size, vermiponics provides more nutrients, so it is possible to grow fruiting plants (tomatoes, cucumbers, etc.). Worm castings are a potent fertilizer, which makes it possible for a vermiponic system to support a wider variety of plants on a small scale than an aquaponic system.

Vermiponics is not good for an income-producing setup. It is difficult to maintain worm bins on a large scale, because they multiply quickly and supply large amounts of potent fertilizer to the system. Unless a system is tailored to one specific crop that needs large amounts of nutrients, vermiponics is best for small applications.

Systems

Vermiponics works best with flood-and-drain circulation through a media-filled grow bed. Worm bins will have a layer of gravel in the bottom covered by a layer of bedding. Vegetable scraps are placed in the top of the worm bin, and the worms will come up and eat the food, pulling it deeper into the bedding.

Soon, this process builds up a layer of nutrient-rich castings. When water flows through the bottom of the worm bin, it dissolves the castings and pulls it through the system into the grow beds. 

One major benefit of vermiponics over aquaponics is that worms are not as sensitive to water conditions as fish are. Worms can also break down food scraps, which eliminates the need to purchase food for the system. However, this can also introduce pathogens into the water that may contaminate plants. 

Bioponics

Bioponics is yet another subtype of hydroponics. While hydroponics uses synthetic fertilizers to maintain nutrient levels, bioponics is focused on 100% organic methods for providing nutrition.

Here’s the tricky part; bioponics can include aquaponics and vermiponics, since they are both methods of providing organic nutrition. However, it can also be a simple hydroponic system where organic fertilizer is substituted for synthetic fertilizer.

The major benefit of a bioponics system is that it provides an organic environment for plant growth, which results in plants that have a well-rounded nutrient profile. Hydroponic systems that use synthetic fertilizers can grow nice-looking plants that are deficient in many trace elements. Organic sources of nutrition help to provide these trace elements, which results in more nutrient-dense crops.

The major drawback of a bioponics system is that it is difficult to control nutrient levels. Synthetic fertilizers are easy to calibrate for a perfect balance of nutrients, but organic fertilizers will vary for each application. Fish and worm waste will depend on the amount and quality of food they are given, which can change on a daily basis. 

Best for/Worst for

Bioponics are best for growers who want higher-quality products, and who don’t mind spending more time on maintaining the system. Organic fertilizers can affect plants, bacteria, algae, and all other life within a hydroponic system. If temperature and pH are carefully regulated, bioponic systems will thrive and create a sustainable ecosystem.

Bioponics are worst for growers who want complete control over the growing environment of their primary crop. Using fish or worms to provide nutrition into a hydroponic system means you must account for the temperature, pH, and light requirements for your plants and your fertilizer source. This can be difficult especially with fruit-producing crops.

Systems

Bioponics includes a variety of different hydroponic growing methods. Any system that uses an organic source of nutrition is bioponic, but the most common are aquaponics and vermiponics.

Organic fertilizers have one major drawback for hydroponic systems; they can cause buildup that leads to clogs. With drip systems, NFT systems, and other systems with small pipes and fittings, this buildup will lead to blocked emitters, anaerobic pockets, and potentially toxic levels of vitamins and minerals for fish and worms.

Healthy bioponic systems will become increasingly more self-sustaining, but unhealthy systems will quickly self-destruct. These systems are best for growers who devote a large amount of time to research, testing, and maintaining their system.

Aeroponics

Aeroponics is an experimental subtype of hydroponics. It is not available to hobby growers unless they are willing to spend a large amount of money.

Aeroponics is a system that suspends plants in air, and mists the roots with a nutrient solution. This can help prevent rot from the roots soaking in water, but it must be meticulously timed so that the roots do not dry out.

Aeroponics does not work well as a bioponic system. The organic compounds that flow through a bioponic system would clog emitters that mist the roots. 

The roots must be in an extremely fine-tuned environment that takes air temperature, water temperature, water quality, light, and many other factors into consideration. This is why most aeroponic systems are commercial operations that specialize in one crop, or multiple crops with the same growing conditions.

Aeroponic systems are only feasible on a larger scale for mass production of one or two crops. At the time of this writing, the only hobby-sized aeroponic systems are expensive to set up and produce less yield than other hydroponic systems.

Conclusion

Water-based growing methods are quickly replacing traditional agriculture, and this means more and more hobby systems will be available for homeowners who want to produce their own fruits and vegetables. Luckily, this is still an experimental field of plant production, which means new systems are being created constantly.

If you want to get into water-based garden systems, do your homework and research how much time each system will take to maintain. Unlike gardens, these systems don’t have natural downtime. You must shut them down if you need to spend time away, and start over when you’re ready to begin production again.

For more information on specific systems, read through our articles on soilless gardening and modern gardening techniques.

Sydney Bosque

Sydney has over 15 years of experience in lawn maintenance, landscape design, and organic gardening. She has an A.A.S. in Landscape Design/Organic Produce Production from the Nebraska College of Technical Agriculture.

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