Urban Ag Issue 4, Dec 2013 | Page 10

“An advantage to the NGS system is the channel can be longer in length,” Baras said. “With an NFT system there can be issues with low oxygen levels if the channels exceed 10 feet. With the NGS system the channels can be 30 to 40 feet long because they run on a pulse allowing plants to dry out and breath between waterings. The NGS system uses channels with multiple layers of plastic similar to a bag inside a bag. The NGS system also uses fewer water emitters than a NFT system.” Baras said a disadvantage of the NGS system is that it is difficult to sanitize. “With a NFT solid plastic channel it can usually be removed relatively easily and dropped into a bleach solution,” he said. “The NGS channels are locked into the system and they are difficult to clean thoroughly with their multiple plastic layers.” Another potential disadvantage with the NGS system is the potential for the plastic channels to tear or to be cut. “Since the NGS channel is like a sheet of plastic it can be cut or torn if workers are using scissors to harvest herbs or microgreens,” Baras said. “This can result in having to replace a whole channel, which are rated to last about five years. A NFT system channel can easily last 15 years or more. The initial cost to install a NGS system is substantially cheaper than a NFT system. But the long term maintenance for NGS can be more expensive since the channels have to be replaced sooner, especially if they are damaged.” For more: The GrowHaus, (720) 515-4751; http://www.thegrowhaus.com. David Kuack is a freelance technical writer in Fort Worth, Texas; [email protected]. An advantage to the NGS hydroponic system is the channels can be 30-40 feet long. 10