You can start your seeds many ways but there are two preferences for me. Above, I've started them directly into disposable plastic cups. Start by filling them about half full with potting soil then sprinkle in 2-4 seeds and cover lightly with more soil. Keep the soil moist, but not soggy. When they first sprout they'll grow two long smooth leaves, just as the second set of leaves sprout (after about 2 weeks, as shown above) add more soil until it's just below the first set of leaves. Your tomatoes will then stay in these cups for several more weeks until ready for transplant!
These seeds I started using my alternate method. I first planted them in just a tiny bit of soil in an egg carton. Just as the previous method, once they started sprouting their second set of leaves, they were ready for more soil, so I transplanted them into biodegradable cups. Fill the cup half full, then simply use a spoon to scoop out your tiny seedling from the egg carton (soil and all) and place them in your biodegradable cups. Add more soil until it's almost to the bottom of the first set of leaves. Another couple weeks and they'll look like the plants pictured above. Notice how the first set of smooth leaves are starting to turn yellow/brown and fall off? That's normal!
Whichever method you chose to start your seeds, once they're about 6-10 inches tall, they're ready to be planted outside! As you can see above, your plants will have formed several sets of large leaves, and they will range in color from deep almost purplish green, to a bright lively green. If you've only planted mass market seeds, you're likely to see only the bright green leaves, but I have found the heirloom seeds I've been saving over the years come in a much greater variety of color.
Check back soon for some tips for hardening and transplanting your tomatoes outdoors. And also, some helpful advice for getting your plants to produce the highest yield possible, since that's what all this works been for after all!