Pumpkins and winter squash are among the most popular vine crops in the garden. The terms pumpkin and squash can be confusing. Pumpkin pie is often made from squashes, and some large squashes are used ornamentally. Scientifically speaking these plants are all very closely related members of the cucurbit family, which also includes summer squash, zucchini, and cucumbers.

Pumpkins come from two different species Cucurbita pepo (most jack o’lantern and some pie pumpkins) and C. maxima (extremely large pumpkins grown for competition and decoration). Make sure to check variety descriptions carefully when purchasing seed. Pumpkins grown for jack-o’-lanterns are usually not eaten, as the flesh is bland and stringy, although the roasted seeds are good to eat. Pie pumpkins often have smaller, sweeter fruit. Some pumpkin varieties produce “naked” or hull-less seeds especially nice for roasting, since there is no hard shell to crack from the seeds. These seeds have lower germination rates, particularly in cool soil, so they are more difficult to grow.

Edible winter squash belong to three different species: Cucurbita pepo (acorn, delicata, and spaghetti types), C. moschata (butternut types), and C. maxima (Hubbard, kabocha, and buttercup types). Some varieties produce small squashes the right size for individual servings, while others produce enormous fruits of fifteen pounds or more, suitable for soups, pies, mashing, or freezing. Some can be stored through the winter; others should be used within a few weeks after harvest. Choose varieties that suit your tastes as well as your ability to handle and store the squash. While a giant Hubbard squash may be attractive as an autumn decoration, a small household may be unable to utilize it as food. Note the days to harvest for the varieties you are considering. Longer-season varieties may be difficult to ripen properly in parts of Minnesota.

http://www.extension.umn.edu/distribution/horticulture/m1264.html