A greenhouse thermal plant comprising: a closed structure (10) covering a ground portion (11)； a thermal plant for regulating the temperature of said closed structure； characterised in that said thermal plant comprises a heat exchanger (12,30) inside said closed structure but external to the ground, and a heat exchanger (15) buried in said ground portion； said external heat exchanger and said buried heat exchanger being connected together； a liquid circulating through said external heat exchanger and said buried heat exchanger； a fan (17) conveying an air flow towards said heat exchanger external to the ground.
