When growing seeds indoors, you control all the variables. The proper mixture of mulch and fertilizer depends on the type of plant, but the cinnamon factor is the same throughout. 
Fill your seed trays with soil, add seeds, more soil, then top with a good sprinkle of cinnamon. Lastly, add water to moisten the soil. 
Seed trays are not the only way to grow plants indoors, however. Fine Gardening suggests using wide, flat containers instead of traditional trays in an effort to keep plants from crowding each other as they mature, while Rodale's Organic Life advises that you can create artificial humidity by using any plastic wrap or glass to suck in the moisture that can be generated by a heating mat or a heater vent.
Cinnamon not only tastes great in food and drinks, but your plants will dig its benefits as well. Make sure to SHARE if you found this tip helpful!