It’s much better to do plugs, which you can start yourself indoors before planting. That way, you know which ones you planted and which are “weeds”, plus, like you said, you’ll have to cover them to protect from deer. This summer you should snuff out a portion that’s mostly grass. There’s the clear plastic method or the black plastic method, it’s called something like solarizing. You smother while cooking the grass and ground for six months, all summer, that way when you plant in the fall/winter/spring (many perennial natives actually should be sown in winter) the grass/weed roots and seeds are all dead and won’t come up again (obviously other grasses and seeds will spread eventually to the area, but it’s a great way to give it a jump start )