I put in raised beds late last year and planted fall crops in 12" squares per the book. I planted several successions of cauliflower, broccoli, rapini and brussels sprouts. The outer rows did great, but the inner 2 rows had spotty performance. The last planting totally failed because by the time it went in the previous plants were large enough to shade it completely.

I re-read the book last night but it doesn't say anything about larger crops smothering their neighbors. So what are the best strategies to avoid this?

Larger squares for larger plants? Logically this makes sense to me, but maybe it conflicts with the overall premise of SFG.

Stagger spacing of large plants? My cole crops are so big, it seems like they would have been a problem for anything smaller nearby.

I appreciate any thoughts on this.