I have been moderately successful in keeping track of what we've brought in from the garden so far this year. My scale is easier to read in kilograms than in pounds, so that's what I've recorded.
The weights don't include smaller harvests, like a few kale or chard leaves brought in to stir into the white bean soup or to put on pizza, and the weights of the herbs (which are also tiny) aren't recorded, but when there was enough of something that the scale read more than 0.1 kg, I wrote it down:
Radish, winter .40
Swiss chard .20
Collard greens .50
Swiss chard .15
Radish, winter .95
Onions, green .45
Beet greens .30
Using a kilograms-to-pounds converter that's available online, I converted the weights to the more familiar pounds and ounces.
Jan. total 2.10 kg = 4 pounds, 10 ounces
Feb. total 4.85 kg = 10 pounds, 11 ounces
2012 running total: Jan. + Feb. = 15 pounds, 5 ounces
That's not a spectacular start to the gardening year, but it's hard to complain. The cool weather veggies require so little tending that counting their weight in the year's total feels almost like cheating. Getting to the summer harvest takes a lot more work - more weeding, more watering, more replenishing mulch.