You will not believe me. I understand that you will not believe me. What I am about to tell you, however, is completely true and is unexaggerated. You can sow seeds all through the winter and in the spring, you will most likely have more plants than you can shake a stick at!
I am a huge fan of a process called winter sowing. I was turned on to it a few years back by the kind folks over at the GardenWeb. There is a Winter Sowing forum that I was encouraged to check out. So many threads from people who were wildly successful with growing plants from seed. I had always thought growing from seed meant light setups, a greenhouse, and lots and lots of work. But the more I read, the more winter sowing made sense--think of it as doing what Ma Nature does, but you're just helping her along a bit. Plants typically go to seed in the late summer/early fall. Those seeds fall to the ground, where they stay until they're scratched up and eaten by birds and squirrels, or they germinate and grow.
To winter sow, you take containers of whatever kind (I use milk jugs, orange juice jugs, whatever I can find--bonus, it's recycling!!), take the lids off, cut the tops of the jugs partially off leaving a "hinge," put potting soil into them about 4" high, press seeds into the soil, moisten thoroughly, tape the tops back on, and set the whole deal outside to face the winter. You do not bring them inside, even when there's a blizzard on the way. Snow, ice, etc. will not hurt your seeds in their protective little homes (for a more detailed explanation go to wintersown.org) .Basically, you're creating mini greenhouses for your seeds. When the temperatures start to rise, you'll see your containers bursting with seedlings. :) My first year I sowed about 110 containers and had enough to entirely fill a 30x20 foot bed, plus I gave dozens of plants to friends, neighbors, complete strangers....you get the picture. Let's just say I was very successful. And my total outlay of cash was about 20 bucks for enough potting soil to fill all those containers.
The two best things about winter sowing (in my opinion) are that it is tremendously cost-effective--just the cost of potting soil and seeds, and sometimes you can get seeds from a friend's garden for free, and it's a good way to recycle all those plastic jugs we accumulate throughout the year.
If you'd like to have a huge, lush, full garden, I really encourage you to look into winter sowing. I think you'll be pleasantly surprised!