Maximum Yield USA 2015 November | Page 76

GETTING TO THE ROOT OF IT ALL If roots require more oxygen than what they can get through replenishment, their function begins to slow, as does the uptake of water and nutrients. Eventually, a lack of oxygen can cause root-cell death and increase the risk of root diseases such as pythium. The more restricted the root zone volume, the greater the replenishment rate of oxygen must be. In hydroponics, this can be achieved in a number of ways. Some grow mediums contain larger pores than others and allow oxygen to diffuse faster down into the root zone. Second, nutrient solutions carry dissolved oxygen, so increasing the dissolved oxygen content of the solution via aeration and making sure the root zone is not oversaturated with water will ensure more oxygen is available for root uptake. Root Competition In many hydroponic systems, plants can be grown in separate containers or slabs of substrate, yet some plants are often grown side-by-side to allow the roots of both plants to intermingle. Some studies have found that plants produce more root mass when sharing space with a neighbor as compared to plants growing alone. It is th