I'll have to ask her how/if she's using fertilizer.

Thanks, walkingman!

nitrogen? Be sure they are getting enough Pand K as well.

But your points about the nitrogen and fertilizer are very good.

Thank you, NRaleighLiberal.

unlike tomatoes, beans. eggplants and peppers, squash have female and male flowers...bees need to bring pollen from the male to the female blossoms

We're not sure if bees are going into the greenhouse. Another poster suggested that she'll have to hand-pollinate the plants.

Thanks again for your help!

This year, on the advice of a neighbor, I have been shaking the plants every day to pollinate them. My plants are full of tomatoes this year.

Once they flower u will likely need to hand pollinate.

but probably not a big factor in fruit production

i just recently learned about pruning and trellising for squashes.
long story short, any leaves below fruit at not doing anything and you should cut them at the stems. this keeps the mildew out.

a good pruning should get it to get down to business, and take back the greenhouse. hack it back to size, trellis it up.
if those leaves aint working, i would feed them to my chickens.