I think you're good. The eggplant will spill over the sides of the bed but if that's ok with what's around it the plant won't care.

Here is a link that might be useful: Sinfonian's garden adventure!

Thanks, Sinfonian. Hey, I was just checking out your personal blog and noticed how well your spinach is doing. How long has it been in the ground? Mine has just sprouted (after 10 days) and had been covered with a homemade hothouse contraption for the last week or so. We received a massive rain storm last night, which is continuing today. Do you think I should keep the seedlings covered or let them out to enjoy the rain? The mix drains so fast that I wonder whether they could really get too much water. Once your seedlings sprouted, did you cut back on how moist you kept the mix?

Thanks again. It appears you and I are both getting our gardening feet wet for the first time and i'd be interested in comparing our progress.