Man-induced soil compaction is a widespread problem for soil fertility and soil usability. Negative consequences may persist for a long time. However, the burrowing activity of soil fauna (pore creation) and growth of plant roots as well as swelling and shrinking can loosen compacted soil over time. This study was focused on the question if an increased energy supply can promote the soil-loosening action of soil biota in compacted soil. We conducted an experiment where compacted soil blocks of two different substrates (different pH) with and without addition of glucose (as energy supply) were exposed to sites with contrasting potentials for restructuring (mown grassland and acidic spruce plantation). Glucose addition stimulated the burrowing activity of soil fauna in compacted soil blocks. Synergism between earthworms and plant root growth had the strongest effect on soil loosening. The site conditions (notably pore-creating biological activity) and the soil acidity of the compacted soil play a key role for the structural recovery. In soil blocks without earthworm activity glucose amendment inhibited rooting by plants, most likely because microbial metabolism led to oxygen deficit in the compacted soil block.