I am a novice gardener and am looking for some advice. I have a very skinny flower bed next to my sidewalk. It is one foot wide by thirteen feet long. It gets lots of sun. I'd like to plant zinnias there this May and I'd like them to be prolific--really take up the whole bed--as opposed to being planted with lots of space between them. How many zinnias would you buy and how far apart (or close) would you plant them?

Thanks for any replies.