Pumpkins

Pumpkin pie, pumpkin pudding, pumpkin bread, and the ever-popular Halloween jack-o-lantern are all autumn favorites. But, did you know that most canned pumpkin puree is actually squash?

Being members of the squash family (Cucurbita), pumpkins and other winter squash share enough characteristics as to be indistinguishable according to the FDA. Huh. How about that? So much for truth in advertising. No matter. Growing pumpkins is rewarding and not nearly as difficult as you may think.

The story of pumpkins​

Pumpkins are native to North America. Early Native Americans grew pumpkins along with maize and beans in the Three Sisters Method. This sustainable gardening method combines the nitrogen-fixing ability of beans with the climbable maize (or corn), and the soil protecting, weed preventing shade provided by broad squash leaves. Ripened pumpkins were roasted over fires, baked in dirt ovens, parched, and boiled. They dried pumpkin flesh and used it as flour, and dried the outer shells to be used as containers. Pumpkin blossoms were added to soups and stews, and any seeds that were not saved for the next year’s crop were roasted for as tasty snack. I don’t see any reason why we shouldn’t be using this durable and attractive plant in the same ways in our own gardens.

How to grow pumpkins
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Pumpkins are now grown everywhere except Antarctica, as human and livestock food, and for use as autumn decorations. Now, I love seeing those round orange signs of a good harvest on porches and patios, but it kills me to see them tossed to the curb, many of them never even opened. What a waste! Unopened pumpkins can always be donated to local food banks, if nothing else. Personally, I put my pumpkins to work for my own family. The easiest way possible, is to simply let nature take its course. You can put a pumpkin in a suitable location to go through all the natural cycles and just leave it alone.

Pumpkin fun in the garden

Over time, even pumpkins wrinkle

If you prefer a more focused effort, you will need seeds. It can start with a store bought packet, seeds from a friend’s pumpkin, or your own current pumpkin. Jack-o-lantern or not, I will eventually cut into my pumpkins. I can put this off for quite a while because pumpkins and other winter squashes, such as butternut, have one heck of a shelf life, if they are cured correctly. We’ll get to that in a minute.

Cutting open the pumpkin, you will find a treasure trove of seeds inside. I remove the seeds and separate them from the stringy threads that nourished them (my chickens love that stringy stuff!). I choose the fattest, firmest seeds for next year’s crop, placing them inside a folded towel to allow for air flow without sun exposure, until they dry. The rest are soaked in a brine and roasted for a family favorite. 

After temperatures have reached a steady 70ºF, those saved seeds are planted in hills, or mounds, of loose soil amended with aged compost or manure. The hills improve drainage and the soil warms more quickly. Pumpkins are very heavy feeders and their seeds are temperature sensitive. Each pumpkin plant can take up to 50-100 square feet, given the opportunity. You can also redirect vines along walkways, lawns, or fences. Plant 4 or 5 seeds 1” deep in each hill. If you have room for multiple hills, they should be spaced 4 to 8 feet apart. After your seedlings are 2 or 3 inches tall, select the best 2 or 3 for each hill and snip the rejects off at soil level. This causes the least amount of disturbance to young roots and important soil microorganisms. If you are growing pumpkins in rows, rather than hills, seeds should be planted 6 to 12 inches apart in rows that are 6 to 10 feet apart, thinning seedlings to one plant every 18 to 36 inches.

Caring for pumpkin plants​

It takes a lot of water to make a pumpkin. During fruit set, each pumpkin plant should receive approximately one inch of water per week. (One inch of water is equal to 0.623 gallons per square foot.) When watering, try to avoid getting the leaves wet, as this can promote fungal diseases. Mulching around pumpkin plants will help conserve water, stabilize temperatures, and reduce competition with weeds. Since pumpkins are shallow-rooted, it is not a good idea to disturb the soil. If you only have a small space, pumpkins can be trained up a trellis. Depending on the size of the fruit, you may need to provide hammocks as support. 

How to hand pollinate pumpkins
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One common problem with pumpkins is insufficient pollination. You can pollinate your pumpkins by hand for a bigger crop. To hand pollinate, you must first learn the difference between male and female flowers. It’s not hard. Male flowers tend to open earlier in the growing season and they feature a stalk that emerges from the center of the flower called the anther. If you touch the anther and your finger comes away dusted in yellow, it is ready to use for hand pollinating. Simply cut the male flower off and remove the petals to create a “paintbrush of pollen”. Female flowers contain an ovary, which looks like a small ball at the base, outside of the petals. Male flowers do not have this structure. Once female flowers begin to open, simply use the anther paintbrushes to apply pollen to the nubby bits (stigmas) in the center of the female flower. If pollination is successful, the ovary and the base of the flower will begin to swell, ultimately becoming a mature pumpkin.

Immature female pumpkin flower

Male pumpkin flower (Vishalsh521) CC BY 3.0

Pumpkin pests & diseases

The most common problem I have had with pumpkins are powdery and downy mildews, with an occasional bout of blossom end rot. Weeks will go by and the leaves will stay bright green and healthy and then, it seems suddenly, the leaves are covered with fuzzy white and gray areas, top and bottom, and production slows to a near halt. Pumpkins are susceptible to other fungal diseases, such as Verticillium wilt, root rot, damping off, and curly top, but I have not experienced any of those in my garden. Many insect pests also enjoy pumpkins. Crickets, earwigs, several types of beetles, stinkbugs, wireworms, whiteflies, thrips, nematodes, armyworms, spider mites, aphids, and, of, course, slugs and snails. Looking at this list, it’s a wonder that pumpkins grow at all, but grow they do!

Pumpkins are ready to harvest when the shell is firm and the stem is shriveled. After removing the fruit from the vine, allow it to dry, or cure, for a couple of weeks in a location with plenty of airflow and cool temperatures. Garages work nicely. After your pumpkin has cured, it will remain edible for several months.

Give pumpkins a try in your garden!