Conclusion
Overall, the experiments show that slime mold grows well in warm and dark environment. It is best to keep samples in 23-25 degrees and covered with dark cloth. Never forget to keep the petri dishes humid. Add about 3 drops of water everyday or 5 drops if the samples are kept on filter papers.
About the medium, it is better to grow slime mold on agar than other medium, such as filter paper or wood chips. But be careful with the cleanness since the contamination could be more serious in agar than other medium. Don't put sugar into agar.
To feed the slime mold, better use fresh and clean oat flakes. Mushrooms didn't show great help during experiments. Remember to add enough food once oat flakes are swallowed by slime molds.