A cotton harvester basket structure includes a closure section connected to a rigid basket by a flexible material such as canvas above and rearwardly of the cotton compacting structure. As the basket is filled, the pressure from the cotton pushes the closure section up to provide only as much volume as necessary to accommodate the added volume of cotton after the basket fills to its normal capacity. Hinged side brackets help guide the lid section during the basket expansion and provide lid section stability, both in the lateral and fore-and-aft directions. After the cotton in the basket is unloaded, the lid automatically returns under the influence of gravity to its lowermost position.