Heating a Greenhouse

Unbelievable amount of work.

Dug out a grave sized trench.  Filled it with rocks.  Added venting to heat exchange with the rocks.  Added a fan that pulled air through the vents.  Installed a solar panels on roof of building next to greenhouse.  This was to power the fan that ran the heat sink.

Made me tired just watching it.  Imagine what it would have been like to do it.  I'm much too lazy for that.  Gotta be an easier way!!!!!!!!!!!!!!!!!!!!!!