Roots grow through the cracks, and the shells add a small amount of calcium to the soil. Another convenient container is a newspaper pot. A tool called a Paper Pot Maker aids in folding a strip of paper into a small vessel perfectly sized for one large seed or several small ones. The pot drains easily, and the newspaper does not deteriorate when damp. If you choose to start a lot of seeds, a small greenhouse keeps the project contained and allows you to regulate several factors that are important to germination.
Problems arise when they start to overwater and expose the new seedlings to cool air right away.
Once the seeds sprout, open the vents on the plastic top so there is air exchange and the humidity level, necessary for germination, begins to drop. The air is still more moist than the rest of the house, but the seedlings are not exposed to drafts. Once the new plants have several sets of leaves, remove the top, and place the tray in brighter light. Gradually get them ready to move outdoors by increasing the amount of light slowly. Remember, plants are just like people.