Greenhouse Build

Daveed and Shunya,
Shams and Julie have begun the dig on the slightly in the ground greenhouse primarily for winter vegetable harvesting. I’ll post some pictures later in the day of the present state of the work.
Also we are considerably expanding the Orchard; as you felt it is just too crowded over there. But are waiting on the building of a shed till next year.
Shams

ORIGINAL INSPIRATION: RASHID’S GREEN HOUSE : NEW ZEALAND

GENERAL BUILD (Question: foundation 36 in sides upon which the hoops rest. We must have some sort of retaining wall on the north & northeast sides, as the earth is several feet higher there)

May go with Raised Beds On Both Sides of Cement Center Walkway

If hoops were mounted on a 36in outer wall we might be able to have two walkways right along outer walks, which would mean 3 walkways.

Question: What would this construction be made of? Would one railroad high be sufficient or is that too low ?