How to Grow Pepitas
Grow Styrian pumpkins for pepitas—hullless pumpkin seeds—and harness the benefits of pumpkin seeds.
When I was young, I loved nibbling on the salted, roasted seeds from a freshly carved jack-o’-lantern. Sometimes I would eat them like sunflower seeds, cracking open the hard hull with my teeth and spitting it out to get at the tender morsel inside. Or I would just eat the seeds whole.
Years later, I discovered pumpkin kernels in a health food store, already hulled and ready for snacking. Sometimes called “pepitas,” these tasty, tender seeds are delicious simply eaten raw and unseasoned, and can also be added to salads or granola, and used in pesto.
Pumpkin seeds contain healthy levels of magnesium, zinc, tocopherol (a precursor to vitamin E), and essential fatty acids. Cold-pressed pumpkin seed oil contains higher levels of antioxidants than walnut, hemp, sunflower or extra-virgin olive oil. The nutritious seeds are also used to treat prostate problems.
To produce hull-less pepitas, you can either grow pumpkins and hull the seeds – a very complicated and labor-intensive method, unless you have a commercial dehuller – or a much simpler way is to grow pumpkins that have hull-less, or “naked,” seeds.
Image by Janet Wallace
The hull shebang
More than 200 years ago, a multigenerational mutation took place in a pumpkin patch in Styria, a region of Austria. The unusual pumpkins had seeds without hulls. Since then, generation after generation of Styrian farmers have saved the seed from the pumpkins with the thinnest hulls, largest seeds and greatest quantity of seeds. The result was that Styrian pumpkins now have large cavities filled with hull-less green seeds containing between 40 and 50 percent oil. A crop can produce up to 1,000 pounds of dry seeds per acre.
Traditional Styrian pumpkins are large plants with vines extending as far as 10 feet. The pumpkins weigh an average of 13 pounds. They have green and yellow or white stripes but turn orange as they mature.
Seed breeders have developed bush varieties of Styrian pumpkins with smaller fruit and early maturation (100 versus 110 to 120 days). These are sometimes called oilseed, hull-less-seeded or naked-seeded pumpkins. An American variety called Lady Godiva has smaller fruit, weighing 3 to 6 pounds. (Think naked seed and you can understand the name.) Kakai is a semi-bush variety with small fruit weighing between 5 and 8 pounds. Dual-purpose varieties, including Snackjack, Eat-it-All, Streaker, Triple Treat and Sweetnut, have good-tasting flesh and hull-less – or thinly hulled or semi-hull-less – seeds.
Similar to jack-o’-lantern varieties, oilseed pumpkins have fairly thin walls and bland or delicately flavored, slightly stringy flesh. The flesh can be used in soups and casseroles, but isn’t as good as pie pumpkins or winter squash for baking. Some farmers keep the seeds and feed the pumpkins to livestock.
Image by Janet Wallace
Growing oilseed pumpkins is virtually identical to growing other pumpkins or winter squash once the plants have germinated. The plants are heavy feeders and thrive on a nutrient-rich soil, but avoid too much nitrogen as this will contribute to lush, green foliage and few fruit. Adding mature compost or well-rotted manure before planting will help yield more fruit.
Hulls are tough skins that protect the seed of regular pumpkins. When you plant oilseed pumpkins, keep in mind that the seeds have no hull, so they are more vulnerable to rotting (particularly in cool, wet soil) and pests. To reduce these risks, help the seeds germinate quickly. Wait until the soil is warm – ideally above 60 degrees Fahrenheit – before direct sowing. Try to keep the soil moist, but not saturated, until the seedlings emerge. Some gardeners plant the squash in raised hills so the soil will be warmer and drier than the surrounding ground – an advantage in cool, wet weather.
Another option is to start seeds indoors in large (at least 4-inch) pots two weeks before transplanting, then plant them on a calm, overcast day once the threat of frost has passed. This can help improve yields in areas with cool, short seasons. Transplant carefully, though, as pumpkins, like other members of the squash family, don’t like having their roots disturbed.
Image by Janet Wallace
Protection from pests
Oilseed pumpkins are vulnerable to the same pests that affect other members of the squash family. Crop rotation and providing habitat for beneficial organisms helps prevent many pest and disease problems. Pumpkins and related cucurbits should not be planted in the same location more than once every four to five years.
Some pests transmit diseases that can have devastating effects on yields. In 1997, the zucchini yellow mosaic virus destroyed 60 percent of Austria’s Styrian pumpkin crop. The virus can be spread by aphids and striped cucumber beetles, and through infected seed.
Spraying neem oil repels aphids and cucumber beetles. Another deterrent for both pests is reflective mulch. Using 1-foot-wide strips of aluminum foil or silver plastic below plants has been found to be more effective at controlling aphids than weekly insecticide treatments.
Floating row covers protect plants from pests but must be removed once flowering begins, unless you are hand-pollinating. Cucumber beetles can also be controlled organically by using Surround (a product containing kaolin clay), vacuuming the beetles, or using zucchini as a trap crop.
Pumpkins are drought-tolerant, but long dry spells will lead to a loss of yield. Provide adequate air circulation and avoid overwatering so fruit will not rot on the vine and to help prevent powdery mildew and other fungal diseases. Spraying milk on plants is an age-old and scientifically proven method for reducing the incidences of powdery mildew. A newer technique is the use of the bacteria Bacillus subtilis, sold as Serenade.
Weeds and wind
Once plants are established, there is little need for weed control. In fact, you might have to rein in the pumpkins to keep them from taking over your garden. But it’s best to control weeds until the plants start to set vines. After that, just pull weeds as needed to reduce future problems.
Styrian pumpkin plants have such large leaves that strong winds can upturn vines and even uproot plants. They benefit from windbreaks and sheltered planting sites. Traditionally, they were intercropped with corn, which provided a windbreak. When the pumpkins matured, the seeds were harvested and made into oil, and the pumpkin flesh was fed to livestock or combined with corn stalks for silage. Today, some growers plant pumpkins between rows of corn 16 to 32 feet apart.
Image by Janet Wallace
Pollination and promiscuity
Pumpkin plants have male and female flowers. The female flowers need pollen from male flowers to produce pumpkins. Bees, wasps and other insects perform the job of pollination.
When it comes to pumpkin pollination, promiscuity is best. For pumpkins and squash in general, the more visits by pollinators, the greater the fruit set, fruit size and weight, and number of seeds. If you’re not saving seeds to plant, you can allow the pollination to happen among any type of C. pepo.
If the flowers haven’t received enough pollen, you might see small, stunted squash that rot on the plant. This often happens in cool, wet weather when few insects are active in the morning to complete pollination. In this case, you can hand-pollinate the plants in the morning. Simply take the inside of the male flower and use it to touch the inside of several female flowers, which can be identified by the small pumpkin at the base of the flowers.
Planting flowers near the pumpkin patch or bringing in hives of bees can increase pollination rates. Commercial growers might bring in a hive of bumblebees for every half-acre of pumpkins to increase pollination rates. Bumblebees are preferred over honeybees because they remain active in cool and damp weather.
Harvesting and curing
Harvest when the leaves are yellow and the pumpkins have turned orange or before a hard frost, whichever comes first. You can remove seeds at harvest or after the pumpkins have matured during storage. The seeds of fully mature fruit have greater oil content than those from immature fruit, but there is a risk of seeds sprouting inside pumpkins during storage. The crop can be stored for several months at temperatures between 50 and 55 degrees at a relative humidity of 50 to 70 percent.
Saving seed for eating is just like saving seed for planting the following year. I chop open the pumpkins and scoop out the innards. I put the seeds and pulp in a glass jar or bucket and cover with cold water for a few hours.
After soaking, I squeeze the seeds from the pulp and rinse in a colander until little or no pulp remains. I spread the seeds on a cookie sheet and leave in a warm, dry place for a few days, or until they are dry enough for storage, stirring frequently. Seeds are dry when the thin cellophane-like coating starts to come off. You won’t be able to easily dent the seed with your fingernail; the seeds will break, not bend. I store them in the refrigerator. The plumpest seeds are reserved for planting, and the rest are for eating.
Image iStockphoto.com/Brendan Delany
What’s in a Name?
What’s the difference between squash and pumpkin? The answer lies in the kitchen. Squash is the general term referring to several species of the genus Cucurbita. Oilseed pumpkins are Cucurbita pepo, the species that includes zucchini, summer squash, acorn squash and many pumpkins. “Pumpkin” usually refers to winter squash used for jack-o’-lanterns or pies.
Pumpkins used for jack-o’-lanterns are usually varieties of C. pepo with thin flesh and large open cavities, which are all the better for carving. Most pie pumpkins are thick-walled C. pepo varieties with better flavor and texture than the flesh from jack-o’-lantern pumpkins. Notable exceptions include C. maxima varieties, including the delicious heirloom called Cinderella – or Rouge vif d’Etampes – and giant pumpkins.
Why is this important? If you plant more than one variety of a species, for example two different C. pepo, they will cross-pollinate. To save seed from your pumpkins for planting the next year, you need to plant only one variety of that species or get into complicated isolation techniques. If you want to save seed from hull-less pumpkins, you can’t grow zucchini, acorn squash or other C. Pepo in the same location.
Janet Wallace is a freelance writer, organic farmer and seed saver. She grows much of her own food at her home overlooking the Bay of Fundy in New Brunswick, Canada. Find more about the author at Janet Wallace.
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