Sounds like great minds think alike! I also planted a ring of clover (that I mixed with some chicory) around the edges. Unfortunately, I was unable to get the brassicas in until the middle of last month and...no more rain. My smaller plot was still damp after that last rain about the 10th of July, so I had decent germination there, but very little on the big plot.
Finally got the rain on Wednesday and Thursday, so after three weeks, my germination looks great!
Last year I was unable to work up my plot and didn't get anything planted until August 10th. Then it didn't rain for 2 weeks, but by the middle of September, it looked pretty good...patchy but the deer didn't mind.
Brian