the plastic. Humidity is key. Plastic sushi containers & to go sandwich packaging make great sealing seed starting trays. Place your seed tray on a warm sunny windowsill, or under grow lights and wait. Many seeds will germinate within the first week others two or three. Some take much longer. Patience is key and you shouldn't throw away failed seeding projects for at least a year. Over the days and weeks, check your trays for signs of growth, if the soil dries out make sure to give it a drink. To water once seeded, place your seeding tray in a larger container of water and let it absorb via capillary action. Once seedlings appear and begin to grow, cut a few holes in the plastic to let fresh air in. Over the course of a week you can slowly but surely adapt them to the outside world, eventually removing the plastic all together. If germination was successful and the tray is looking overcrowded, avoid the urge to transplant your seedlings. I don't know what it is about over crowded seed trays but the little newborns seem to thrive in these close conditions. Premature pricking out sometimes leads to failure, I find it much safer to transplant once the seedlings start to look like little plants. Even though they might look deformed in these tight conditions, once you transplant them they'll correct themselves. Another thing to keep in mind is to avoid changing the environmental conditions of your seedlings too quickly