Hydroponic AeroGarden Seed Starter Tray-homemade

I want to get the seed starter tray for my Aerogarden, but at the $ I couldn't do it this year.  So I have some foam insulation board at the right depth so I thought I would try making my own. 

http://www.aerogarden.com/media/wysiwyg/kbase/GST70PLayoutPlantingGuideSeedingList.pdf