Maximum Yield USA 2015 November | Page 106

AEROPONICS 2.0 A eroponics 2.0, a.k.a. high-pressure aeroponics, is different from the aero systems that first appeared commercially in the ’90s. These systems produce a very light mist that floats around in the air and looks like fog, so the term fogponics is often used to describe this style of growing. In a fogponics system, water and nutrients are atomized and distributed in a mist with droplets in the range of 30-80 microns. A droplet of 50 microns is the optimal size roots can uptake, as dete rmined by NASA’s research on aeroponic potatoes in the International Space Station during the ’90s. Because most droplets in this range are lighter than air, they float around the root chamber until colliding with roots or other obstructions. The root chamber remains humid with roots dangling in air, which is why it is called an aeroponic system. For the atomization and mist to occur, an external, high-pressure pump is needed instead of the submersible, pond-style pump that is typically used in aero systems and usually produces low pressures (under 4 psi). To produce the mist or fog, pumps must run pressure in the range of 80-100 psi. Low-pressure aeroponics uses low-pressure, highflow pumps, whereas high-pressure aeroponics uses high-pressure, low-flow pumps. For this reason, the mist is extremely gentle and floats around like a fog in a properly tuned high-pressure, aeroponic system. In a fogponics system, water and nutrients are atomized and distributed in a mist with droplets in the range of 30-80 microns.” 104 Maximum Yield USA  |  November 2015 High-pressure aeroponics is the most efficient way to grow. Ultrasonic Foggers There is another kind of fogponic system that includes the use of an ultrasonic fogger, much like the kind found in humidifiers. With an ultrasonic fogger, a small ceramic plate is vibrated by an oscillator more than one million times per second and creates droplets only 3-5 microns in size. This thick fog can actually suffocate roots because it displaces available oxygen. However, if the root chamber is well-aerated and properly cooled, the roots will be under the right conditions to grow. With enough oxygen and the proper temperatures, cuttings often root faster in this type of system. However, with greater rewards come greater risks in the sense that the roots are extremely sensitive to high-temperatures and lowoxygen levels. Using a lower dose of nutrients when using ultrasonic foggers is recommended because the salts of the nutrients can damage the equipment. In addition, the nutrient mix cannot be easily carried in a fog consisting of such small droplets. For this reason, this type of set-up is best suited for propagation and early vegetative cycles. For flowering or fruit production, nutrient-craving plants perform much better with a droplet size closer to 50 microns, which can fully support the plant’s hunger for nutrients. Growing with HPA High-pressure aeroponics (HPA) is the most efficient way to grow, as NASA determined with its aeroponic potato production. When this type of efficiency is achieved, roots develop fine hairs called trichoblasts that are more efficient at taking up nutrients and can provide a higher rate of growth than roots growing in other methods. This style also happens to use the least amount of water and nutrients possible, which is what motivated NASA to give it a try, as it looked for ways to minimize cargo costs for space missions. When cloning or germinating with HPA, it is important to provide the roots with enough humidity so they can develop a strong root system. This is done by setting timing cycles so they are almost always on, or with a shorter ON/OFF ratio than later on in the growth cycle. After roots have developed, it is good to dial back ON times and increase OFF times. This will be done continually, from the time of initial rooting until later in