What weed killer can I use in my vegetable garden?

Help! I have a garden full of plants and now weeds. I was going organic and using only organic fertilizer weed preventer etc but I have weeds everywhere. What can i use that won't kill my plants or ruin the soil for future seedlings? (I will be harvesting the lettuce and plating turnips soon). Organic methods preferred but at this rate I'll use anything that'll work and save my plants!