Hydro 101

What is hydroponics? Hydroponics is the growing of plants without soil. Literally from the Greek “hydro” meaning water and “ponos” meaning work; growing plants by letting the water do the work. Hydroponics uses a nutrient rich mixture of water and fertilizer to feed plants. By delivering the plant food directly to the root system the plant saves energy it would have used looking for food. This saved energy is redirected, allowing the plant to grow bigger & faster.

Is hydroponics a new technology? Hydroponic gardening dates back hundreds, possibly thousands, of years. Hydroponics was used in the hanging gardens of Babylon. The Aztecs used floating rafts to grow food. Ancient Egyptian hieroglyphics allude to hydroponics in the BC era.

Why grow hydroponically? Is there something wrong with traditional soil farming? Traditional farming is fine. However, one of the largest threats of pollution we face is the agricultural runoff of fertilizer into the water table. Hydroponics produces almost no runoff pollution. Hydroponic gardening also uses up to 90% less water than traditional soil farming, has faster growth rates compared to traditional farming, and hydroponics allows any piece of land (even those with poor soil or little water) to become a productive farmland.

Are there different types of hydroponic systems? Yes, there are several different types of hydroponic systems. Most differ in the way in which the fertilizer/water is delivered to the plants. The different types include: NFT, deep water culture, ebb & flow, drip, aeroponics, raft culture, kratky, and passive. These types are described in more detail below.

NFT (Nutrient Film Technique) is a hydroponic technique where a shallow stream of water and fertilizer (which contains all 16 essential elements to support a very shallow stream of water) containing all the dissolved nutrients required for plant growth is re-circulated over the bare roots of plants in watertight gullies, also known as channels.

Deep Water Culture (DWC) is a hydroponic technique where plants grow suspended (usually in a net pot filled with LECA stone) over a reservoir of water and fertilizer which is being super oxygenated (bubbled) using an air pump and air stone. The splash and humidity supply the necessary moisture to the plant’s roots while allowing the root to maximize its growth with a constant supply of both oxygen and food.

Ebb & Flow Hydroponics is a hydroponic technique that is known for its simplicity, reliability of operation, and low initial investment. Pots are filled with an inert growing medium which anchors the roots and functions as a temporary reserve of water and fertilizer. The pots are then placed in a growing tray. These growing trays are periodically flooded with a mixture of water and fertilizer which drains back into the reservoir; the process repeating several times per day.

Drip Hydroponics is a hydroponic technique where water and fertilizer are pumped through a manifold of tubes, pipes, or ducts which then drip down beside a plant or group of plants potted in an inert growing substrate. The number of plants and arrangement of plants is highly variable making this a popular option for commercial growers and hobbyists alike. In some instances the water / fertilizer mixture is recaptured and sent back to the reservoir (termed recycled), while in other instances it is not reclaimed (termed run to waste.) This technique has been modified in garden and landscape irrigation (think soaker hoses) as a method of supplying water to chosen areas without the waste associated with conventional sprinklers and other irrigation equipment.

Aeroponics is a hydroponic technique that has proven to be very effective at growing robust plants quickly. In aeroponic culture plants are grown in net pots that allow the plant’s roots to hang suspended in a dark, humid chamber where they are misted or sprayed with a mixture of water and fertilizer. As the roots are hanging down in air (hence the name Aeroponic) they are able to absorb the maximum amount of oxygen they can utilize, at the same time they are feed a concentrated fertilizer and water mixture which allows for the greatest rate of plant growth. These systems are highly productive, but do require a greater degree of attention as the misting/spraying devices are prone to clogging.

Raft Culture is a hydroponic technique that is not much more than a simple raft which floats on a pool of nutrient-laden water with plants suspended above the raft & their roots submerged in the nutrient water below. This technique is used by commercial farms and hobbyists predominantly for the growing of lettuce. One benefit of this type of system is that it is possible to control bolting in lettuce by cooling the water temperature even though the air temperature would normally cause crop failure.

Kratky Method is a hydroponic technique that is very new. It contradicts some key elements of established hydroponic theory in that there is no water movement, no added oxygenation, and no reservoir changes. The plants grow in a container which starts out full of water/fertilizer and then as the plants absorb the water; the water level drops and the plant grows longer root to reach the water below. Then the roots suspended in air begin to absorb oxygen for the plants. This is an amazing system (only for growing lettuce and leafy greens) that can be done with minimal investment, minimal time constraints, and produces a great crop. We are very pleased to share more information on the Kratky hydroponic method with our customers.

Passive Hydroponics is a hydroponic technique that relies on capillary action to move the water/fertilizer mixture to an area where the plants roots can absorb it. It is essentially a self-watering planter that utilizes a wick of one sort or another to maintain adequate moisture for the plant to grow. Many traditional hydroponic growing mediums are not suitable for passive hydroponic culture because they do not have enough hydrophilic capability (they do not absorb enough water). Recommended mediums for passive hydroponics include coconut and diatomite.

Is one type of hydroponic system better than another? Yes and no; some types of systems are better suited to certain types of plants based on size, fertilizer or oxygen needs, and efficient use of space. All systems, however, share the benefits of directly feeding the root system, thus expediting the growth rate.

Can any plant be grown hydroponically? Just about any plant that naturally grows in soil can be grown hydroponically. When growing a plant hydroponically, special attention must be paid to match the particular pH and PPM a plant requires with that provided by the hydroponic system. Visit the Atlantis Hydroponics® Tips & Tricks page for a list of ideal pH & PPM levels for your fruits, flowers, vegetables and herbs.

What is pH? pH is a measure of acidity and alkalinity. It is a logarithmic base 10 scale ranging from 1 to 14 with 7 being neutral, 1 being most acidic, and 14 being most alkali. Most plants growing hydroponically thrive in a range of 5.5 to 6.2, although you should check the link above for specifics regarding your chosen crop.

What does PPM mean? PPM or parts per million is a numerical value given to illustrate the amount of fertilizer is in a solution. PPM is based on conductivity, and as more fertilizer is dissolved into water it becomes more conductive, thereby increasing the PPM. The ideal fertilizer levels vary greatly based on type of plant, plant size, and plant age. For specific information regarding your particular plant’s needs please check the above link.

What kind of fertilizer do I use? Can I use Miracle Grow®? Unfortunately most houseplant fertilizers like Miracle Grow® are designed to supplement the nutrition found in soils. Hydroponic gardening necessitates that all mineral nutrition for the plant be provided by the fertilizer; therefore, it is recommended that a fertilizer designed specifically for hydroponics be used.

Do I need grow lights or a greenhouse? It is not necessary to use grow lights when growing hydroponically provided you are able to provide the intensity of light your particular plant requires. If you plan on growing indoors with little to no natural sunlight it will be necessary to supplement the available light with either ViaVolt® T5 fluorescent grow lights for low light plants like lettuce or ViaVolt® HPS/ MH Grow Lights (High Pressure Sodium or Metal Halide) which are better suited to high light plants like tomatoes or peppers.

Can I build my own hydroponic system? Yes you can build several types of hydroponic systems but be careful to use only food grade components like plastics, adhesives, and sealants if you plan on growing consumables like fruits or vegetables.

Hydroponically grown plants are not nutritious… Hydroponically grown plants are as nutritious as or more nutritious than the majority of crops grown via the traditional method. Much of the farmland used by traditional farmers has been depleted of minerals by decades and decades of improper crop rotation and heavy use. By providing a balanced and full complement of minerals and vitamins directly to hydroponically grown plants they are able to absorb that nutrition at a rapid rate and in turn provide those minerals and vitamins to you when eaten.

Hydroponically grown fruits and vegetables are flavorless… The fact is that some hydroponic (and soil grown) plants are not as tasty as we would like. The reason for this however has little to do with the method by which they were grown and everything to do with genetics. The large scale producers of fruits and vegetables have selected for genetic traits like increased size, resistance to disease, and visual appeal over flavor. Let’s face it, most of us pick produce at the grocery store by visual appeal over taste because it is considered wrong to bite into a tomato to decide if it tastes good or not. By growing your own food hydroponically, you can always have the tastiest tomato because you choose the genetics or strain.

Hydroponic crops can not be organic… This is just not true. There are several organic fertilizers available designed specifically for hydroponic growing. Also there are several agencies (like OMRI the Organic Materials Review Institute) that test and certify hydroponic fertilizers as being 100% organic.

Hydroponics is not environmentally sound… If anything hydroponics is more ecologically sound and environmentally friendly than any other type of traditional farming. Hydroponics uses less water, less fertilizer, grows more food per acre, and allows complete control of runoff water to prevent ground water contamination.