Now is a Great Time to Seed Lettuce
Really, it's just about one of the easiest veggies to grow! In the DFW area, you can grow salad greens from September through May of the following year! And growing your own beats paying $7.99 a pound for organic greens at the store.
You'll want to direct seed lettuce into the garden now. Lettuce seeds need light to germinate so just sprinkle them onto moist soil surface and press down gently. Do not cover with soil! Because seeds are exposed, you'll need to be diligent about keeping the soil surface moist until germination (consistency of a wrung out sponge). As seedlings sprout and put on their first set of true leaves, you'll then want to thin out seedlings so that remaining seedlings have room to grow.
While you may want to harvest entire heads of lettuces such as Romain or Butterhead, it's not necessary. You can do what is called loose-leaf haresting on these plants from fall through spring. New leaves emgerge from the center of the plant and then splay outwards. Simply snip off leaves as they reach about 4-inches and continue harvesting around the plant as it grows.If you do want to harvest the entire head, then do what is called "succession planting". Sow new seeds in the garden every 2-3 weeks.
Lettuces are biennials, meaning they will grow foliage the first season, and then bolt, or flower, the next. So after warm temperatures hit in late spring/early summer, your greens will bolt and you'll need to stop harvesting. Pitch leftover plants into the compost bin! Feed your greens with an organic veggie food every couple of weeks (liquid) or monthly (granular).