Tomatoes are warm season plants. These prolific, low-maintenance vegetable plants can't tolerate frost, so starting the seeds indoors and later transplanting to the garden gives them a head start on the growing season. Sowing your own tomato seeds is much less expensive than purchasing nursery seedlings, and you have many varieties to choose from. Starting tomato plants indoors requires a minimal investment of space and time, and the return is sturdy, healthy tomato transplants ready for the garden in spring.
Fill individual seedling pots with a sterilized potting mixture. Make your own by mixing 1 part sterilized compost, 1 part peat moss and 1 part coarse sand.
Water the soil until it is evenly moist but not soaking wet. You can do this by placing the pots in a tray of water and letting the soil absorb water through the drainage holes until the soil surface is moist.
Sow two tomato seeds per pot on the surface of the soil. Cover with a 1/8-inch layer of soil mix.
Mist the top of the soil with water from a spray bottle just enough to moisten it. Cover the pot with a plastic bag and place in a warm 65-75 F room to germinate.
Remove the plastic when the seedlings emerge and place the pots in a sunny window or under grow lights. Keep the soil moist at all times, watering as necessary.
Thin each pot to only one seedling once the second set of leaves has appeared. Cut off the weaker seedling at the surface of the soil, being careful not to disturb the remaining plant.