Your lemon plants are 2 inches tall. Now you must use potting soil and moisten the soil slightly, then cover the top of the pot in which you planted it with plastic wrap to reduce evaporation so that the seed and soil will not rapidly dry out. As the soil begins to dry, add a little water, but be sure the soil does not become soggy. The pot in which you planted the seed should have drainage holes so that surplus water may drain away when you irrigate your seed and later the seedling.

Keep the pot with seeds in a warm location, such as the top of your refrigerator, until the seeds germinate. For this first period light is not necessary, but once the seedlings begin to appear, they will need light. If they are in a dark location, move them to a location which receives several hours of bright light each day. Direct sunlight is not necessary, but bright light is necessary.

An interesting thing about citrus seeds is that you may get several seedlings from each seed. One of these will be from the embryo formed due to pollination in the orchard, but the others will be "apomictic" seedlings which are vegetative produced. That means that the apomictic seedlings will be exact genetic reproductions of the tree on which the fruit was formed, they are clonal seedlings. The one seedling produced by pollination will not be clonal as it will carry genetic material from the pollen parent (father) as well as the seed parent (mother). In any case, you should have a lemon tree, and it will very likely produce tasty lemons in about 15 years! I thought you would want to know that it will take a long time unless you graft from the seedling to a mature lemon tree. A mature tree may often be purchased at a nursery in the house plant section. There are dwarf house plants lemons from which you may also choose. Grafting may reduce the time for fruit production to only 5 years or so.