We’ve tackled how flexible hydroponics can be and its wide application – from deserts, flooded rivers, to your kitchen countertop. But can it operate in a place man has never conquered – the seas and oceans?
Building a hydroponic system on a boat is possible. Active hydroponics systems can operate on a boat given the availability of electricity and fresh water. Passive hydroponics can be deployed onboard without the need for electricity. The success of a hydroponic system on a boat depends on the 1) type of vessel and 2) the body of water the vessel is situated in.
The complexity of a hydroponics system can vary greatly. There are some big factors that should be taken into consideration even before attempting to build one on a boat.
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It is possible to grow hydroponically on a boat. Floating farms are now becoming a new source of sustainable products due to increasing demand. These floating farms not only grow plants hydroponically but also livestock.
Large companies have already gone to work to make this concept more commonplace as the amount of arable land has become less and less due to desertification, urbanization, and other external factors.
80% of the world’s sustainable land is already in use and it is heavily used for crop production damaging its fertility. Turning to the natural bodies of water to produce food sustainably addresses a key issue of land utilization.
All hydroponics systems can be built almost anywhere, even in a boat or ship. However, the nuances for growing hydroponically will be affected by 1) what your vessel is and 2) which body of water it is located in.
The type of boat you have will determine if you have the facilities for growing such as electricity for the active components in hydroponics (i.e. pumps, grow lights) and watermakers. Where the vessel is situated will also affect the possible sources of where to get suitable water for a hydroponics system.
The most suitable vessels for hydroponics are liveaboards – trawlers, houseboats, catamarans, motor yachts, sailboats, and express cruisers. These boats have enough space and modern amenities such as generators, water tanks, and watermakers for a hydroponics system to function optimally.
As the name suggests, liveaboards are vessels modified for a person to live in during an extended period of time. These vessels have adequate living quarters, restrooms, and water tanks to sustain passengers and plants alike. A roof to cover the hydroponics system is also desirable because it allows the plants to grow under controlled conditions barring weather and heat.
In general, the larger the vessel is, the more space, amenities, and utilities it will have, hence the better it will be for a hydroponic growing space. Water tanks and generators are important because they provide fresh water and energy to the electrical components of active systems like in DWC, NFT, and Ebb and Flow. This is even more apparent in residential ships, storylines, and cruise ships which can provide all of these and more.
Small boats or high-performance boats are not suitable for hydroponics because these vessels are purpose-built for their respective markets such as short-term water activities like fishing or watersports. These do not have the adequate space or amenities to be suitable for hydroponic plant growth.
The source of water is a key factor in hydroponics since the growing method revolves solely around clean and nutrient-rich water. Where the vessel is located has a direct effect on the water available.
Lakes, rivers, and other bodies of freshwater offer a simpler source of water for hydroponics. Water from these sources, if adequately clean (or cleaned) and with caution, can be directly used for hydroponics.
Freshwater is considered anything with less than 1,000 ppm of dissolved salts. Freshwater also has an average acidity (pH) of 6-8 depending on the surrounding soil and bedrock, with surface water having higher acidity compared to deeper water.
It is always good practice to test the water with a pH/EC tester and a TDS (total dissolved solids) before using it for hydroponics. A visual inspection of the water is also needed to make sure that the water is not polluted or full of harmful organisms.
Oceans, seas, and areas where freshwater meets seawater cannot be used for plant growing unless the plant has evolved to adapt to saltwater. The majority of soil plants cannot grow in saltwater because this negatively affects the osmosis process in plants because the salt in the soil dehydrates the plants.
Saltwater or saline water has more than 1,000 ppm of dissolved material, the most common being salt (or so-called sodium chloride – NaCl). Saltwater also has an acidity (pH) of 8. These characteristics make them ill-suited for plant growing.
Saltwater has almost no conventional use such as drinking, irrigation, or industrial application. It only has a few niches uses such as slightly brackish water (~2500 ppm) being used for irrigation in Colorado but not much apart from that.
Water tanks stored in boats can be used to sustain a hydroponics system. Water in these tanks is often tap water sourced from the shore.
Tap water often has a total dissolved solid count of ~100 ppm and an acidity of ~7 pH making it extremely suitable for plant life. This is the same water used coming from faucets, showers, and pipes and the same water we use for plants in gardens.
The best option to have safe and consumable water on a boat is to install a watermaker. Watermakers use reverse osmosis to convert saltwater or freshwater to potable drinking water by forcing high-pressure seawater through a semipermeable membrane which filters out bacteria, organic substances, and mineral salts.
Watermakers are expensive to install and operate, with prices ranging from $3,500 to $11,000. Operating them will also require the boat’s generator system to be turned on to provide electricity for the watermaker. However, the pros heavily outweigh the cons.
Water makes have the benefit of producing clean, drinkable water which can be used for consumption and cultivation. Clean water is preferred in hydroponics because it ensures a sterile growing environment wherein plants do not have to compete for nutrients and oxygen with other organisms in the water.
The ability to produce water in the middle of any body of water is a huge benefit for growing plants and being out in the open water in general. The other practical benefit of watermakers is that this also reduces space and weight since storage tanks and other water containers are not as necessary.
A 120-volt reverse osmosis (RO) watermaker can produce 40 gallons (151 liters) of water per hour which is adequate for the 40 gallons of water needed for cooking, cleaning, laundry, and bathing.
Other vessels which cannot support the same utilities of electricity and watermakers, may opt for a Kratky Method set up. The Kratky Method is simply a deep water culture variant which does not have active electrical components (i.e. air pumps).
The Kratky method can work on almost any enclosed container, the most common being jars. It only requires a certain amount of freshwater mixed with nutrients. The plant roots will gradually absorb all the water in the reservoir, leaving more space for oxygen for the roots.
This entirely passive system does not require electricity to keep it in operation. Its small size, simple construction, and low maintenance makes it an attractive option for growing inside vessels.
Other passive techniques such as Wick and Drip techniques are also viable but they may not be as space-efficient or simple as Kratky. In the case of rough waters, a complex hydroponics setup may not be the best option for the sake of stability and simplicity.
The point of growing on the seas, oceans, or other natural bodies of water is simple – food security and self-sufficiency. The ability to produce food consistently without the need to procure on dock saves on time and cost.
Storylines, cruises, and residential ships are beginning to have inhouse farms to meet food demands during voyages. This acts as a possible buffer on food supply in case of an emergency. It can also increase voyage durations for residential ships. However, we need to note that often the food grown cannot entirely sustain the needs of two or more people due to the space required.
From a practical standpoint, growing hydroponically on vessels lessens the need for frozen provisions for long-duration voyages and the dumping on the soil when entering the territory of countries that forbid the import of soil and plants.
From an aesthetic standpoint, growing hydroponically can provide shipbuilders and designers new and inventive ways to add an aesthetic tinge of green to the otherwise claustrophobic interiors of ships. These can be further augmented with aquariums and other aquatic life to produce aquaponics systems.
Finally, since hydroponic systems use less water and nutrients than conventional soil cultivation, it leaves a lesser carbon footprint as well. These factors combined leave greater reason to push growing on vessels.
The greatest benefit of floating farms is food security and reducing the environmental impact. These systems can be used in conjunction with aquaculture and livestock to provide a sustainable food source without the trappings of conventional soil cultivation.
Areas with limited arable land, seasonal flooding, or coastal areas can turn bodies of water into avenues for agriculture. The products of these floating gardens are high quality without leading to the usual problems of conventional soil cultivation which are limited space, desertification, and soil quality degradation.
Advances with more efficient photovoltaic (PV) solar panels also decrease the carbon footprint needed by these vessels to provide electricity to lights, watermakers, and pumps. The use of biodiesel fuel also provides a sustainable source of energy.
- Hydroponics can be practiced on a vessel. Active hydroponic systems require generators or batteries to keep them operational. Passive systems do not need electrical components to work and can be used in any space, boat included.
- The type of vessel will affect the nuances of growing hydroponically. Liveaboards and larger vessels are more suitable for growing hydroponically because of the space and amenities available.
- Water source is an important consideration. Freshwater from freshwater bodies can be used but with caution. Saltwater cannot be used. The best option to have potable water available on either fresh or saltwater is a watermaker.
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