I started these indoors, but stuck them outside for a while today since it's not too hot yet. I'll bring them back indoors well before nightfall so they don't get too cold or eaten up by random night creatures before morning.
The little plastic cups are super cheap and linked here on Amazon.com. Way better than those little biodegradable seed starter pots because these are re-useable so I only had to buy them once! Just pop out the seedling along with the dirt, re-fill & re-use. They also stack really well for storage!