approx 6ft x 9 ft...would be able to grow about 1 dozen tomato plants, or 12 - 18 cabbages, or 3 rows of carrots, parsnips etc. Probable about 12-15 lettuces...it is a very small plot, but with very small amounts of each you could grow all of the above.
I have a 1/2 acre so that is why i say the above is small...you have to make the most of what you have :)