Mary H. Meyer, University of Minnesota Professor and Extension Horticulturist
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Squash and pumpkins can store for several months, if harvested at maturity and properly cured. (Click to enlarge.)
I love winter squash! So with the more than 100 kinds grown at the Arboretum this past summer, it was fun looking at the huge variety and deciding which ones I would try cooking this winter. I settled on 8 'new-to-me' kinds: orange hubbard, fairytale pumpkin, autumn crown, Queensland blue, marina di chioggia, rouge vif d'etampes or cinderella pumpkin, crown, large world of color blend, and 1 'old' favorite: blue hubbard, see photo below. You can still find winter squash at the markets and you can make plans this winter to grow your own squash next summer. Winter squash are easy to grow, have high nutritional value, and some kinds store well for several months. If you can still find open Farmer's Markets, you will likely have a much better selection of squash and pumpkins than the one or two kinds available in the supermarket.
Pumpkin and winter squash were cultivated by the American Indians for centuries and are native to North America. Pumpkin is derived from the French word pampion meaning "sun-baked squash", which was modified to pompkin and finally to pumpkin.
What is the difference between a pumpkin and squash?
The scientific name of most pumpkins, and acorn, delicata, and spaghetti squash is Cucurbita pepo; these fruits have very hard stems or petioles, which cannot be dented with your fingernail.
Winter squash usually has a softer, wider, pulpy stem or petiole, which you can penetrate with your fingernail. Most of the large fruited types, the HUGE award winners, 'Boston Marrow' and 'Mammoth' are Cucurbita maxima, along with many kinds including buttercup, kabocha and hubbard squash.
The third species is the buff-colored butternut squash, these oblong beige fruits are Cucurbita moschata, and are excellent for baking and pies. This species is usually sold as canned pumpkin.
The 2011 pumpkin and squash display in the Great Hall at the Minnesota Landscape Arboretum.
Although all kinds of pumpkin and squash are edible, they vary in consistency, texture, color, and flavor. Some may have flesh that is several inches thick with a small seed cavity, while others are thin fleshed with large seed cavities, making them inefficient to process and bake.
What squash or pumpkin is best to grow in Minnesota?
Most winter squash and pumpkins can be grown and mature successfully in Minnesota, especially central and southern areas. In general, the larger the fruit, the longer the growing season required. Any variety that matures in 100 days or less should produce mature fruit in Minnesota. Varieties that need 120 days will likely be successful only in the southern portion of the state. Most are direct seeded in the field. It is important to know the days to harvest for the varieties you are considering.
Winter squash require full sun, plenty of space for their long vines, and adequate moisture. After growing to maturity on the vine, harvest fruit before any injury from frost. Although appearing to be tough and firm, all curcurbits are tropical plants and do not do well in cool or cold weather; frost can damage the fruit and prevent the rind from curing properly and long storage.
After harvest, clean the rind with a soft cloth to remove any soil. Store the fruit at 80° to 85°F with 75 to 80% relative humidity for approximately 10 days to cure the fruit. Curing heals wounds, helps ripen immature fruit, enhances color, and insures a longer post-harvest life. Curing is beneficial in pumpkins and some winter squash, but 'Butternut,' 'Hubbard,' and 'Quality' squashes have not shown any added benefits from curing. Curing is detrimental in Acorn types, and will hasten senescence. After curing, the fruit can be stored at 50-55 degrees but no cooler, and it can be held at room temperature if 50-55 is not possible. Store cut pieces in the refrigerator.
Immature fruit will not fully develop indoors. Fruit that is mature green, may ripen further indoors but will not have as high nutritional value, or flavor. Color change is often important, as most squash and pumpkins turn from green to orange, beige, blue, pink or yellow, at maturity.
Nutrition and Cooking
While all squash and pumpkins are edible, some have more sugar and flavor. If the fruit is fully mature, it will remain firm and can actually improve in storage, for 3 to even 6 months, if the rind has been cured properly and is not bruised. Acorn squash is an exception; it is not a 'good keeper' and should be used within a month of harvest. Cucurbita pepo, true pumpkins, acorn and spaghetti squash have long fibers and some cooks prefer winter squash because they are non-fibrous. Regardless of the type, cooking is similar for all squash or pumpkins, however, the large ones are much more difficult to handle and peel. By far the easiest way is simply by cutting the fruit in half, removing the seeds and baking it cut side down. Rubbing the edges with olive oil, or butter prevents adhering to the pan.
Winter squash is a good source of complex carbohydrates and fiber. Research suggests that the soluble fiber in foods such as squash can play an important role in reducing colon cancer. Winter squash is also a source of potassium, niacin, iron and beta carotene. Usually, the darker the orange color, the higher the beta carotene content. Beta carotene is converted to Vitamin A, which is essential for healthy skin, vision, and bone development. The nutrient content of winter squash can vary, depending on the variety, maturity and condition of the fruit. The following information is a summary of all varieties, cooked, baked and cubed:
Nutrition Facts (1 cup cooked, cubed)
Protein 1.8 grams
Carbohydrate 18 grams
Dietary Fiber 5.8 grams
Calcium 28.7 mg
Iron 0.67 mg
Potassium 895 mg
Folate 57 mcg
Vitamin A 7,291.85 units
I have vine borers in my squash, how can I control them?
Vine borers are difficult to control effectively with insecticides. You can reduce potential damage the following season by disposing of infested plants. Vining types of squash can be encouraged to root at the nodes, giving the plant some ability to withstand attacks of vine borers. Some success in control of an active infestation may be achieved by carefully splitting open areas being fed upon and removing the larvae. Late planting of short maturing squash, planting after July 1, after which the adult has laid its eggs, may avoid borer damage.
North Carolina State: http://www.ces.ncsu.edu/depts/hort/hil/hil-24.html
A beautiful book on squash: Goldman, A. 2004. The Compleat Squash: A Passionate Grower's Guide to Pumpkins, Squashes, and Gourds. Workman Publishing.