If you frequent the green section on instructables you will likely find many biodegradable seed starter options. This is an adaptation of another similar seed starter idea www.instructables.com/id/How-to-make-organic-planting-pots-using-old-newspa/
The main difference is that the ones I have created are much smaller and more convenient for small jobs (they also keep you from having to use very much soil to germinate the seeds).
Step 1: Materials
Toilet Paper Roll (all used up - just the cardboard)
Potting Soil (seed starting soil works best)