A healthy and vigorous root system is essential in soilless plant cultivation. The primary function of roots in soilless systems is water and nutrient uptake. Root nutrient uptake has three characteristics: (1) selective, (2) accumulative, and (3) genotype dependent. Many factors can affect root health and root water and nutrient uptake. To create and maintain a healthy and vigorous root system, it is important to take an integrated rootzone management approach, considering the above characteristics and all the environmental factors. This chapter is a review of our current understanding of root, rootzone, and rootzone management in soilless systems; and it also discusses future research directions in this area.