the film im thinking of seems made in either late 80s or early 90s,
& would have aired on disney channel..
some kid is working on a science project to grow tomatoes,
& ends up using his formula on himself & becoming an adult like in big
then he dates his teacher & for whatever reasons has to be a kid again
so he comes up with an antidote, & confesses to the teacher
the next day theres a substite & a new blonde girl in class,
implying the teacher took the antidote to be a kid again
theres also a tomato the size of a basketball at one point

so any ideas what this film is?
its more obscure than the peanut butter solution..

my memory of the blonde girl at the end looks alot like Amanda Peterson,
but no luck checking her credits..

Try that.

"You see a pumpkin seed. I see possibilities."

I'm pretty sure it's that film, yeah. However, for a simple sci-fi film, it's really, really fantastical. Who would believe a 30-year-old teacher would want to get with her 14-year-old student?

Yup, it is 14 Going on 30

That only happens in Florida.

I seem to remember the alternate ending for Big had the grown up woman showing up in Josh's class as a child again.

yup thats it!
given the title im surprised i didnt stumble on this one by accident.. thanks!

& apparently the girl i remembered as being similar to Amanda Peterson was Amy Hathaway..
http://www.imdb.com/name/nm0007115/