Broadcast means that if you don't care if your plants grow in an organized way, like in rows, just toss the seeds out, press into the soil with a board, and toss some soil on top of them. Then thin so they aren't too close to each other (which they wouldn't be if you had planted them one-by-one). This can work for small seeds bearing small plants like radishes, but I'm not sure why anyone would want to do it for more major veggies. It can be a time saver in planting, but probably not in cultivating and harvesting.
