There are about as many ways to start seeds inside as there are gardeners, with a few basics we all need to consider.
You're trying to fool your seeds into thinking it is spring, when the sun is closer and the days are longer. You can do this with any 'cool' light bulb such as a fluorescent light, supplemented with natural light if possible. Some gardeners leave the light on 24 hours/day, but we personally prefer to turn them off at night. Place your light as close to the seedlings as possible, about 2-4" is best. If they have to stretch towards it they may get leggy which is indicated by long thin stems. This can cause your seedlings to fall over and die.
Adjustable lighting works well for us, as we can raise the fixture up as the seedlings progress.
You'll need the most warmth when the seeds are germinating. Up to a point, the warmer the seeds are the faster they will sprout. We don't use supplemental heat personally, but rather germinate in an area of the house where there is a heater. You can buy heating mats, or check out some of the homemade set ups using strings of lights or heating pads. Always use necessary precautions of course.
Seed Starting Medium
Again there are a few options to choose from. You can buy Jiffy Pellets, we have found them to be inexpensive and work well. You can also buy prepared seed starting mix, and use anything from homemade paper pots to 1/2 toilet tissue rolls turned into pots. Some people prefer to make their own mix, most often by combining peat moss, vermiculite and perlite. This is light enough for the seeds to push through, while also holding in some moisture. You can also add a small amount of fertilizer if you wish.
We have killed more seedlings by forgetting to water them than anything else. Once they are established plants they can take some neglect, until then these little babies are like any othera and need attention.
Many gardeners either cover the seed trays with a plastic lid or plastic wrap, thus creating a greenhouse effect and holding the moisture in longer. You can also keep them moist by using a clean spray bottle to mist them.
Whatever you do, just don't let them dry out.
So here's what to do:
1. Determine what, how, where and when to start seeds.
2. Place in growing medium and moisten.
3. Cover and keep warm, moist and close to the light.
One last tip I was given: Having a fan blowing nearby can help your seedlings develop stronger stems.
Here's a guide for when to start seeds. Just mark your last spring frost date on your calender, and count backwards.
Here in Zone 5/6 and with the use of a cold frame and mini greenhouse to help extend our season, we will be starting seeds next week.