I'm not a gardener (unless you consider a few pots of herbs on a Manhattan windowsill a garden), but I'm familiar with the concept of the garden journal. The idea is that in order to prepare for next summer's growing season, gardeners note the weather, growing conditions, and results each day. That way they'll know whether it might be a good idea to plant their sunflowers a little earlier next year, and they'll know which vegetables should be ready to harvest in mid-July.
My version of a vegetable garden is the local Farmer's Market. And since I'm a novice at this whole seasonal-produce thing, I thought I'd adapt the garden journal to a market journal. I bought a classy little notebook that's small enough to carry with me to the market so I can write down what I bought, whom I bought it from, and even what I later cooked with it. If you're like me, you'll forget which heirloom tomato had the best flavor by this time next year, and having it all conveniently jotted down will avoid monumental mistakes.
The Apica notebook I bought is a Japanese import--only a couple of bucks but sturdy and small enough to put in your pocket. I picked mine up at Spoonbill and Sugartown in Williamsburg, but they're avail on the internet as well. Any notebook will do, of course, but how many other brands carry such an appealing example of Japanese to English translation gone awry? "Most Advanced Quality Gives Best Writing Features," is proudly displayed on the cover of my new Apica.