My husband would say one.
Our first year married, I wanted to go all domestic, so thought I'd plant a garden. My grandfather had a garden. We grandkids were never allowed in it. But it was huge -- house-sized huge. So guess how big I wanted my first garden? Yup. Just like my Granddaddy's. But, what to plant? I wasn't really into vegetables, except eating corn, carrots and peas.
I asked farming neighbors in our new community, and was told zucchini was easy to grow. I'm not sure I ever even tasted zucchini before that. I read the instructions on the package, and then proceeded to plant three seeds to every hill until all the seeds were gone. Zucchini grows like magic. No matter how many you pick, the next day all you have to do is lift a leaf to find another.
Not wanting to waste food, I experimented with the stuff. Today, when I even mention the word "zucchini," my husband turns green.
A few years after that first garden, I actually self-published a cookbook called "The Zucchini Cookbook -- 101 recipes, including a 5-course meal with zucchini in each meal; games included." Stupid title, but descriptive. I printed it on green paper, which was rather pukey, looking back on it. I discovered some favorite recipes, but someday will figure out how to cut them back to one-person-sized.
How much zucchini is too much? Maybe, if I ever plant it again, I'll only sow one hill with two seeds.