“These microbes also require oxygen,” he said. This can seem counterintuitive in a hydroponic system because the roots are sitting in water, but the tops of the plants look like their wilting if there isn’t any oxygen in that water.” As the flow rate increases in a NFT system, more oxygen is delivered to the roots so water isn’t sitting in the channel as long.īaras said the need for oxygen in an organic hydroponic system is even more important because of the presence of living microbes in the fertilizer solution reservoir. Low oxygen in the root zone can appear as wilting at the top of the plants. If there isn’t any oxygen in the root zone no water will make it up through the roots to the top of the plant. “But there is a stage where the plants use energy to actively pull up water through the roots. “Most of the water uptake in plants is passive,” he said. In our hydroponic NFT system I have been aiming for about 1-2 liters per minute.”īaras said oxygen is necessary for plant roots to perform metabolic processes. In conventional hydroponic NFT systems the flow rate is about ½ liter per minute. This allows freshly oxygenated water to be delivered quickly to the roots. As the flow rate increases, more oxygen is delivered to the roots so water isn’t sitting in the channel as long. “For NFT, it appears more oxygen can be delivered to plant roots when the flow rate is increased per channel. This is an effective method for increasing dissolved oxygen. “This can happen in multiple stages where the water will drop several times. “This can also be done in vertical farms where the water will fall down large return pipes to the reservoir,” Baras said. As water returns it is allowed to fall and break the surface of the reservoir so that the water can pull in oxygen. There is the benefit of moving around the solution and the air being drawn in increases the level of dissolved oxygen.”Ī method that organic growers use to increase oxygen levels is cascading the water when it returns to the reservoir.
“As the pumps operate they draw in air through a ¼-inch emitter. “The pumps aren’t injecting air into the irrigation lines, but simply into the reservoir to circulate the water and to create a circular flow within the fertilizer reservoir,” he said. In the conventional production systems Baras is studying he has installed water pumps with a Venturi attachment to add oxygen to the nutrient solution reservoir. Tyler Baras, special projects manager at Hort Americas, is studying methods of adding oxygen to both conventional and organic hydroponic production systems. We have removed all air pumps and air stones from the organic systems we are trialing. In organic systems these tend to be hot spots for biofilm development. “A lot of times in conventional hydroponics, growers use air pumps and air stones to add oxygen. “One of the big differences is how growers add oxygen,” Baras said. Tyler Baras, special projects manager at Hort Americas, is studying methods of adding oxygen to both conventional and organic hydroponic production systems in the company’s 12,000-square-foot research and demonstration greenhouse in Dallas, Texas. Oxygen is critical in the development and growth of edible crops grown in hydroponic systems such as nutrient film technique (NFT) and deep water raft culture. Growers have affordable options for ensuring plants receive sufficient oxygen in hydroponic production systems to maximize growth and to reduce the chances of disease.