Hydroponics
In its most basic form, hydroponics is the practice of growing plants without soil. In a hydroponic setup, plants receive all their nutrients directly from water instead of soil. They are grown in an inert medium such as gravel or coco coir fiber, which provides no nutrients but gives the roots something to hold on to in order to keep the plant upright. The roots of hydroponic plants draw nutrients, oxygen and carbon dioxide directly from the water.
Hydroponic fruits and vegetables are typically grown within a greenhouse or other isolated environment, where plants are protected from harsh weather, insects, and disease. This kind of isolation makes hydroponics an ideal environment for organic produce, since every exposure is closely managed and there is no need for insecticides or toxic weed treatments.
In agriculture, primary crops are those which come directly from the land and are consumed without having undergone only minimal processing (washing lettuce, carrots and berries, for example). For these crops grown in hydroponics systems, regulations stipulate that only potable water be used, since viruses, bacteria, and other toxins could easily be transmitted to the humans who consume the produce, and the simple act of washing does not completely remove all germs.
In addition to using potable water to supply the plants throughout their growth process, potable grade materials are used for growing apparatuses, tank liners, and for any equipment or tools involved in harvesting, cleaning and preparing the produce for sale. Using materials that meet the highest standards for food safety throughout the hydroponic process ensures that your produce is protected from contamination. Failure to use durable, food-safe materials could result in health issues for yourself or your family, or even a lawsuit if you sell your produce to others.
Aquaponics
Aquaponics is a hybrid between Aquaculture (discussed in our next article) and Hydroponics. In Aquaponics, fish or other aquatic animals are grown together with plants, and the waste products from the fish provide nutrients for the plants, while the plants purify the water for the fish. Aquaponics attempts to closely mimic the natural cycles of nature and presents excellent opportunities worldwide to produce high quality, fresh food, even where that hasn’t been possible in the past.
In aquaponics systems, water from the fish environment is circulated among growing plants and returned to the fish tanks. One advantage to aquaponics systems is that very little water is wasted - the water is naturally enriched and purified throughout the cycle. But this also means that any contamination from tank liners, pumping equipment, grow beds, etc., can accumulate and concentrate. This makes it vitally important that the materials in aquaponic systems be carefully sourced for the very highest quality and reliability. Food grade and fish-safe products are simply not enough. Chemicals and plasticizers in liners marked as fish-safe are not safe for human consumption, and even food-grade plastics can degrade over time and release harmful contaminants.
Potable Grade Materials (NSF/ANSI 61)
When you’re choosing materials and liners for your hydroponics operations, make sure they’re specifically tested for food safety. Even better, look for a certification from a group like the NSF, with ratings of 61 for this kind of use. This rating is required for potable water use, so it’s above and beyond what’s required for safe food production. NSF-61 liners are tested over long periods of time to ensure that even when the material eventually breaks down, it doesn’t change what’s released into the water.
Another, more practical and immediate concern when growers are selecting liner materials for their fish and plant habitats is the issue of pH variation. Even food-safe liners can raise the pH of water. It’s common for many PVC and EPDM lined ponds, in fact, to stay around pH 7 despite repeated efforts to keep it lower. If you’re planning on growing plants that need a slightly acidic or even perfectly neutral solution, use a durable, reinforced polyethylene (RPE) liner that won’t react with the water, change the pH balance, or release harmful chemicals into it. BTL Liners’ Aqua Armor line offers a variety of products that are NSF/ANSI 61 certified and meet these requirements.
