Abstract: A U-shaped flexible tray for a compost bin having a rear wall, a front wall and a floor. The ends of the front and rear walls are releasably attached to upstanding mounting posts. Organic material is deposited into the bin and aerated, thereby forming compost. A tarp cover protects the compost from wind and rain. A forced air system beneath the bin forces air through the organic matter to promote composting. The composted product is unloaded by a bin emptying device having an upper roller that draws the rear wall forward, and a lower roller that draws the front wall forward, thereby shifting the weight of the compost. As the rollers tighten, the flexible tray is transformed from a U-shaped bin into a vertical wall, thereby moving the compost out of the bin. The flexible tray is then manually restored to its original mounting posts and the U-shape restored. The bin emptying device may advance on tracks to the next designated bin to resume emptying operations.