By Steve Diver
NCAT Agriculture Specialist
Root-zone heating is a greenhouse production method that focuses on an optimum root temperature by distributing heat to bench and floor growing systems. It is an appropriate technology in the
sense that it promotes energy conservation in modern greenhouse production. To warm roots, hot
water is distributed through EPDM rubber tubing (also known as hydronic thermal tubing) or PVC
piping laid out in a looping pattern. Though modern greenhouses typically use natural gas or fuel
oil to heat water, alternative energy sources include geothermal, solar, wood, thermal biomass
(heat from compost or brushwood piles), and co-generation. The benefits to plant growth from
root-zone heating systems are well documented.