Citrus peels make an excellent starter pot for acid loving plants. A lemon, an orange or grapefruit can be hollowed out and used as a starter pot. It's biodegradable and as it breaks down it provides additional nutrients your seedlings will need as they develop. Plants that do not tolerate highly acidic soil should not be placed in these Do it yourself pots.
Eggshells are another household item that makes a nifty little seed starter.
Eggshells are lightweight and a tad fragile. Eggshell seedling pots over time will enrich the soil with calcium, magnesium and other nutrients that are essential for many plants to prosper.