Growing plants from seed is a good way to inexpensively populate both flower and vegetable gardens. Although buying seedlings can sometimes be a more reliable way to propagate plants, growing from seed allows you to grow varieties of flowers and vegetables that may not be readily available in your local nurseries. Growing from seed is not difficult if you start with fresh, viable seeds. With proper planting and care, you might even find a few seeds that will sprout from older, heirloom type seeds.
Sterilize your soil if you are using potting soil. Sterilize the soil by placing moistened soil in a metal pan in a 200 degree F oven for around 30 minutes. If you have an old meat thermometer, the internal temperature of the soil should register between 130 and 140 degrees F.
Augment your sterilized soil with peat moss, vermiculite, or perlite if the soil doesn't drain well. Only start seeds in a soil that drains well. The amount of soil augmentation you will need will depend on the soil you are starting with. A good rule of thumb is to add between 1/3 and 1/2 vermiculite to most common home potting soils.
Run any plastic pots or seeding trays through the dishwasher to remove any potentially harmful contaminants. However, peat seeding trays are an excellent alternative because you can plant the entire peat pot in the garden once the seedlings have grown.
Fill your seeding containers to about 3/4 inch from the rim with your well drained, sterile sprouting soil.
Place the seeds either on the surface or cover as indicated on the seed packet. Different seeds will have differing planting depth. If your package doesn't indicate depth, plant the seed about twice as deep as the seed is wide. For example, if your seed is around 1/8 inch wide, plant it 1/4 inch deep. Plant several seeds per pot to ensure that at least one viable plant forms.
Water the seeded pot gently with a spray or drip. The soil needs to be moist, but not dripping. Try not to flood the pots as this can cause the seeds to move too far down into the pot.
Cover the pots with plastic wrap to keep humidity levels high and place the pots in a cool, dark room until they germinate. Room temperatures between 60 and 70 degrees F are ideal.
Move the seedlings into full sun over a 2- to 3-day period once they germinate. Moving them into the sun too quickly can result in the sun killing the young plants.
Once you see the first few true leaves, cull the weaker plants. Leave only the one strongest plant growing in the starting pots.
Once the seedlings have reached around a foot tall, depending on the plant, transplant them in to larger pots or into your garden after the risk of frost has passed.