This paper discusses two approaches to enhance multi-site scheduling for grid environments. First the potential improvements of multi-site scheduling by applying constraints for the job fragmentation are presented. Subsequently, an adaptive multi-site scheduling algorithm is pointed out and evaluated. The adaptive multi-site scheduling uses a simple decision rule whether to use or not to use multi-site scheduling. To this end, several machine configurations have been simulated with different parallel job workloads which were extracted from real traces. The adaptive system improves the scheduling results in terms of a short average response time significantly.