My co-worker actually suggested this to me and I was surprised that I never thought of it myself! When we started our garden, we started documenting our progress… mostly by pictures (of course, you see them on here!).
But for my daughter (and my son when he gets of the age where he can understand), this gardening quest was more than just pictures. It was an opportunity for her to write down what she sees, how things are growing, include the pictures that we are taking and learn a great deal from our experiences!
Having a Gardening Notebook is a fantastic idea and can help you learn (via documentation and visualization) first hand from your experiences. It can offer a quick reference if a problem arises and it’s been a while since you’ve working with a particular vegetable or flower