I'm after some advice on how best to build a greenhouse base. I currently have a 10 X 8 foot greenhouse on a 100 X 100 mm treated wooden perimeter base. This base is sat directly onto soil and is well over 10yrs old now. Not sure how it's anchored if at all, but the greenhouse frame is screwed into the wood which is badly rotten and needs replacing. I've been tempted to replace like for like but am now thinking of a perimeter base made from concrete blocks as this wont rot. The inside of the greenhouse will be kept as a gravel walkway and a raised bed for growing. My question regards the footings for the blocks themselves. Can I dig a trench, fill with compacted hardcore and lay the blocks directly onto that or do I need to pour a concrete strip footing. I've looked online and some info suggests a concrete footing (more expensive) and some info suggests that you can lay direct onto soil on a (semi dry mix???) as the blocks would only be 1 block in height. I figured my initial thought of using hardcore would fall somewhere in middle and give me a solid foundation on a lower budget???