If you live in a location with a short growing season, you will need to start flower or vegetable seeds early--indoors or in a greenhouse. This adds several weeks onto your growing time, before you plant the seedlings outdoors after the last frost in your area. Starting seeds early can give you the same flowers or vegetables found in locations with a long growing season.
Use clean food containers or paper cups for planting your seeds. Poke a few small holes in the bottom of the pots. If you like you may purchase fancier containers from your local nursery or garden center, but it is not necessary.
Fill the containers with purchased potting soil, up to 1/4 inch from the top. Commercial potting soil is free of insect eggs, weed seeds and diseases, making it the perfect medium for starting seeds. It is also full of nutrients, which means you don't have to add fertilizer to the soil.
Follow the directions on the back of the seed packet for the depth to plant the seeds. Use the same directions as given for planting directly into outdoor soil. Every seed is different. Smaller seeds will be planted closer to the top of the soil and larger seeds will be planted deeper. Leek seeds are planted at a depth of 1/4 inch, for example. A good rule to use is to plant the seed three times as deep as the seed is long. Gently move soil over the seed hole.
Place all of your plant pots in a plastic or metal tray and place it by a sunny window. Mist the soil with a water bottle sprayer. The soil should be moist, but not overly wet. Keep it moist and soon the seeds will germinate (pop through the soil). Continue to keep the soil moist with the water sprayer.
Transplant your seedlings when the last predicted frost has passed in your location. Always follow the seed packet for directions in spacing the plants.