Fill a clean tray with an organic soil-free seed-starting mix that has been moistened with water. I prefer a mix that’s one part milled peat moss and one part vermiculite, with some perlite. Make shallow indentations using a long side of a ruler or a paint-mixing stick. This keeps the rows straight and neat. The depth depends on the type of seeds; follow the directions on the seed packet.
Place the individual seeds at the proper distance apart in their rows, following the directions on the packet.
Using the ruler or stick, carefully cover the seeds with planting material. Press the soil down lightly.
Using a watering can with a fine rose, give the trays a gentle soak, but do not over-water. Place the seed trays in a warm location, such as on a waterproof heating mat used for germination or on top of your refrigerator. When sprouts appear, move the seed trays to a sunny window or under a grow light so they will become strong and green.