Maximum Yield USA 2016 June | Page 155

G rowing plants in an aeroponic system is simple if certain environmental parameters are met. For example, if your water temperature never reaches above 64°F, bad biology and enemies of aeroponics such as algae and root rot can hardly begin to grow, much less thrive. Maintaining your water temperatures below 64°F requires keeping ambient room temperatures below 72°F, and this can be quite a challenge, especially in the summertime. A water chiller may be necessary to keep the reservoir cool. You may also need to invest in air conditioning or more efficient lighting to shield the root chamber from the heat caused by some grow lights. Many unseasoned aeroponic growers overlook these steps and accidentally allow their roots to cook in between spray cycles. They eventually notice the plants are struggling with early stages of roots that have likely contracted water molds such as pythium or phytophthora. These problems are also commonly found in hydroponic systems when water temperatures are not kept at reasonable levels. However, because aeroponic roots are dangling in the air with no medium to provide an advantageous microclimate where evaporative cooling can occur, aeroponic systems are much more susceptible to pathogen problems. It’s time for some troubleshooting. Troubleshooting If plants begin to slow down in growth and vigor, this is the first sign you need to pay closer attention to what’s going on. When plants look like they are suffering, there is likely a problem with the environment, pathogens or pests. Take a look at your growing environment first. What are your temperature and humidity levels? Are these parameters providing plants with the “ When plants look like they are suffering, there is likely a problem with the environment, pathogens or pests.” environment they need to grow? What works with soil, soilless or hydroponic gardening may not work as well with aeroponics since roots are exposed and hanging in the air. The growth chamber is under a light and can be heated up even more than the surrounding air. For this reason, reservoir temperatures must be kept lower so the water can cool the roots when they are sprayed. Roots are typically misted every 1-4 minutes so they can be kept at the proper temperature by the cooler water in the reservoir. Spraying roots with an aeroponic system will help avoid root aphids, fungus gnats and so on from laying eggs on the roots in the mist pattern, but aeroponics does not completely prevent these types of pests. They will still find ways to reproduce in an aeroponic system by finding areas to lay their eggs that are safe from the spray. Be on the lookout for common growroom problems, but keep a close eye on the roots. They need to be healthy and thriving at all times to maximize the benefits offered from aeroponics. Discoloration can occur when using certain nutrients that are slightly tinted, such as humic or fulvic acids and organically mixed nutrients. For this reason, color is not a reliable indicator of root health and vigor. Observe the ends of the roots to verify they are healthy and growing new tips. In addition to browning, rotting roots will develop a slimy coating and immediately lose their vigor. Clogged nozzles are perhaps the most common problem associated with aeroponics. Fortunately, they are completely avoidable. Clogged nozzles result from the infrequent cleaning of filters, pumps, tubes and fittings. Another common culprit is allowing the system to dry out after harvesting and before cleanup, which leads to nutrient salts accumulating on the inside of the plumbing. When the system is turned on again, these salts break apart and the solids can easily block the nozzle’s orifice. Likewise, nozzles will often clog before harvest time if the filter is not kept clean. Clean the filter in between sprayings, or temporarily power off the pump, leaving the filter assembly submerged to prevent air from entering the lines. Maintaining a Healthy System Maintaining a healthy aeroponic system can be achieved by keeping a sterile reservoir and grow system, or by inoculating and maintaining a population of beneficial biology into the reservoir and grow system. Both of these methods will maintain a healthy system even though they are virtually opposite from one another. In a sterile system, growers use hydrogen peroxide, enzymes or other similar products with their nutrient mix or in between feedings to keep things clean. On the other end of the spectrum is the inoculation of good biology to prevent the bad biology from Maximum Yield USA  |  June 2016 153