Starting plants from seed is much cheaper than purchasing plants from a nursery, and it gives you a greater choice of plant variety in your garden. Seeds are usually started indoors before the last predicted spring frost to give them a jump start on the growing season. This allows more mature plants to move into the garden, producing flowers or vegetable harvests earlier than those started outside. Starting indoors also gives plants a higher survival rate, as they are protected from insects and many diseases during their first few weeks of life.
Mix together one part sterilized compost, one part peat moss and one part vermiculite in a large bucket. Water the soil mixture until it is just moist. Cover and let sit overnight.
Fill seed-starting pots or flats with the soil mix. Firm the soil lightly but don't compact it.
Sow two to three seeds per pot, or space them 3 inches apart in rows for flats. Plant each seed to a depth twice that of its width, or sow very small seeds directly on the soil surface and cover with 1/4 inch of vermiculite.
Place a plastic bag over pots and cover flats with plastic wrap. Place in a warm room to germinate, which usually takes seven to 21 days. Check the seed packet for light requirements during germination; some seeds require light, others don't.
Remove the plastic when sprouts appear. Move the seedlings to a bright, sunny window or place under grow lights.
Thin seedlings to one per pot when they begin forming their second set of leaves. Cut off the seedling you are thinning at soil level with a sharp pair of scissors.