I'm unsure whether you are referring mostly to ornamentals or vegetables. What kind of plants are you wanting to consider growing?

If you are talking about vegetable gardening, a helpful publication from the UT ag extension service is linked below. It will give planting times and a lot of other information about most popular vegetables.

Here is a link that might be useful: Growing Vegetables in Home Gardens

I'm actually interested in both. I haven't gotten much from my veggie garden the past 2 months, except for some watermelons and sunflower seeds. It's just been too hot!

As far as flowers go, I'm hoping some fall planting will give me better success. I've been trying direct sowing, winter sowing in containers and starting seeds indoors, but success there has been spotty. My indoor growing area is limited to a table lamp on top of the refrigerator. Not a lot of room, and the lamp is so tall that seedlings get leggy. Winter Sowing went ok, but our crazy weather left some drowned and others dried out. With springtime direct sowing, I had trouble with weeds growing faster than the flowers, and not being able to tell what was a weed and what was a flower. So now I want to try to just get some perennials and re-seeding annuals going to fill in the space. Then I can concentrate on growing other flowers a few at a time, and popping them in there as I can.

direct sowing - Some things do best when direct sown, but it depends on the plant. Many things that don't like root disturbance and some vegetables are best when planted this way.

winter sowing - This is often a less labor intensive solution. If you use milkjugs/2-liter bottles and poke drainage holes in the bottom (like frequently suggested in the Winter Sowing Forum), you shouldn't have to worry about the seed drowning or drying out. Do remember to provide partial shade so that the seeds don't cook in the covered containers.

indoor sowing - This is the method I use for most of my seeds. I have a large rack system loaded with fairly closely spaced florescent bulbs of the right frequency (some 4100 K and some 5000 K) to approximate sunlight and timers to control the on/off cycle. Of course, when fully loaded, it does add to the electric bill. I tend to plant many of my seeds about a month before the last expected freeze date. Some adjustment may be needed for especially slow or especially fast growing plants.

You can actually do quite well with just a goose-necked florescent desk lamp. The flexible neck of the lamp allows adjusting the lamp down close to the soil. I do mine on the counter top in the laundry room. For heat, a heating pad underneath. I'm able to do all the tomato and pepper seeds that way end of Jan. I use plastic sleeves from Oreo- type cookies (woo-hoo!) to get lots of seed started. Then when sprouted, move up to tiny cell packs.