When shopping, I try to buy items in season and stock up when the price is right (usually at the farmer's market) and preserve...eat...and enjoy. Items that spoil quickly, I put right into whatever I'm making. I also keep long storage veggies on hand stocked up like one would keep flour on hand...carrots, onion, potatoes, garlic...
When growing a garden, I usually know what I'll be getting out of it (unless there's crop failure or some rampant pest in the garden.) Our meals typically have some element of garden food in them. But the problem is...I don't always know a week or two ahead when I'll be getting that item out of the garden. For example, if I planned to have salads with chicken for next Tuesday, but the lettuce gets eaten by a chipmunk...I could go to the store and buy lettuce, but that wouldn't be saving me money by meal planning. So instead I look at what I have, and go from there.
The other issue with meal planning is that my husband works odd hours. Some days he gets home at 4:00. Some days he says he'll be home at 4:00 but because of an incident, doesn't get home until 11:00pm...and other days, he knows that he'll not get home until late and I have to pack a dinner for him. Occasionally, he'll end up in our neck of the woods at lunch time due to a meeting and I'll need to throw something together quickly for him. Because of this, I keep a well stocked freezer, cupboard, and fridge. I am able to cook things he doesn't like on nights he'll be late...or take something out of the freezer and throw it in with his lunch so that he has dinner...and occasionally I get to be the wife that at a minute's notice can whip together a wonderful filling meal at noon for a surprise family time.
I have tried to do meal plans, but it just doesn't work for me. My stocked pantry works for our family best.
Which type of kitchen person are you?