Root growth and development in soilless culture – a review

Soilless cultivation largely supports specialty crop production systems, where field-grown fruit and vegetable crops continue to transition to containerized production techniques. These soilless systems mostly utilize porous soilless substrates to maintain an optimal balance of air and water, and retain mineral nutrients needed for crop production. Unlike in field production, where roots have the opportunity to explore the vast soil profile, 100% of the container-grown rhizosphere is restricted to the container volume. Therefore, containerized crop roots are subjected to different environmental conditions and growers employ different production management decisions, which are primarily designed to support yield (fruit, flowers, and vegetables) and foliage productivity. However, plant root health and quality can have direct influences on crop development, growth, and overall plant performance. Thus, root growth, while not always a priority, continues to be an important consideration in horticultural research. Growing scientific evidence continues to expand our understanding of how substrate characteristics impact root growth and development, particularly with container-grown roots. As soilless substrate science continues to evolve, it is important to identify not only optimal growing media for specialty crop production, but also substrate impact on root growth and development. Several soilless materials are used in these production systems to attain desired hydraulic and chemical characteristics, which can modify root growth and performance. Accordingly, this paper will serve as a review which explores root responses to soilless cultivation systems and substrate-root interactions.