For fall, I go with radishes, kholrabi, carrots, and peas. However, outside of the radishes, which only take a few weeks, you may want to get rolling on the beds right now. For what it's worth, I am in zone 4/5, kind of right on the border, so I err on the low side at 4. I plan to sow my sugar snap peas and kholrabi in mid to late August, and radishes will be successively planted starting in late August up until it gets too cold, which can sometimes be as late as November. I dunno what "end of summer" constitutes for you, but technically speaking, that'd be the fall equinox in September, which is pretty late.

Joe

In addition to the lettuces and spinach, winter onion plants if you start the seeds now. Try a short day variety like Granex. Broccoli again if you start the seeds now so the plants will be ready to set out as soon as the beds are made. Brussel sprouts and beets too.

Dave

Zone 6 here--you can plant winter lettuces as late early September, and spinach a little after that. But that's pretty much all. Other fall and winter crops must be started now or soon--beets, carrots, collards and kale now; turnips, Asian radishes and escaroles in early August. Savoy cabbages will go in next week, but they were started in flats in June.

Thnks for the suggestions! I went ahead and threw a few spinach seeds in pots few days ago and they are already sprouting!