Hi Dean,
I'm sorry you thought wrong. Spaghetti squash and zucchini will cross with each other. They are both Cucurbita pepo. Now if you had grown a hubbard squash which is Cucrbita maxima and the zucchini this year, you would of been ok. Banana squash is Cucurbita maxima so that is why it crossed with your hubbard.
When I buy seeds for squash, I always record the second name aka species name(if not on the packet) so I know what I can save seeds from or plan to grow only one from each species.
There's
C. pepo ~ zucchini, acorn, spaghetti, and yellow summer are the most popular
C. maxima ~ Hubbard and Banana as you found out are two popular ones
C. moschata ~ Butternut is the most popular
C. mixta ~ Cushaw is a common one in this group
Pumpkins can vary by variety of which group they belong.
Anyway, as long as you know the second name, and pick one from each species, you can grow 4 different types each year and save seeds without problems.
Remy

thank you Remy.

i read the "Seed to Seed" book but then i lent it out and if i had it i would know better. well this year we separated the banana and the hubbard and the zucks and the spaghetti in my garden. the crossed spaghetti happened in my friends garden.

the banana were along side of the potato patch and when we mowed the potato tops we found another banana. it was slightly sut by the mower blades so i cut it open to save seed. i got another 500 nice fat seeds.

today we dug 1/6 of our potatoes and we got 1500 pounds.

it has been a good year for us.

i would still like to know how many seed you get from on seed pod.

Dean

Hi Dean,
I'm glad I could help. Wow, you are really growing a lot of potatoes! Good to hear you had a good year.
I pulled out my Seed to Seed book, and it doesn't tell how many seeds average in a onion seed head. I do figure it is quite a bit since all other allium family plants I've saved seeds are generous with their seed.
Remy