Yes, your shed does need a base. This is to give it a solid, level foundation. Open soil will not help with the longevity of the shed itself or the contents within. The best materials to use to make your shed base are concrete, natural stone or wood.
Killin
Killin is a village situated at the western head of Loch Tay in Stirling (formerly Perthshire), Scotland. The west end of the town is superbly sited around the beautiful Falls of Dochart, the primary road leading down towards the Loch at the convergence of the rivers Dochart and also Lochay. The falls are crossed by a slim, multi-arched rock bridge lugging the major A827 road right into Killin. Killin train station was on the Killin Railway. The railway station was formally closed on 1 November 1965. Killin has a tiny primary school with 56 students. For secondary education pupils travel to Callander 21 miles (34 km) to the south. The local Gaelic tool primary is in Stirling, 37 miles (60 km) to the south.