How to Grow Pumpkins
Let this be the year that you carve a jack-o-lantern that you grew in your own backyard. Pumpkins are not difficult to grow even in raised beds or containers. Start with a classic orange one or try something different. Today, you can find pumpkins that are yellow, white, blue-gray, green-striped — even oddballs like Black Futsu, a 3 to 5-pounder with knobby skin.
Do You Have Enough Room?
Pumpkins grow on long vines—some extending 20 feet or more. If you're planting in a raised bed or garden, choose a spot where vines have room to ramble. In a raised bed, plant pumpkins near the edge of the bed so you can train the vine over the edge, leaving the rest of the bed for other plants. When the plants are young, it's easy to direct the vines where you want them, but you'll want to leave them be once the vine starts flowering and setting fruit.
If you don't have a lot of space, consider a smaller variety, such as Jack Be Little. The bright orange fruits are inedible, but they sure are cute. Another option: look for "pie pumpkins" or "sugar pumpkins," which have a more compact growth habit. These dual-use pumpkins are good for carving and eating. Unlike large pumpkins, these 4- to 6-pounders have flesh that's sweeter and less stringy. To save even more space, consider using a Cucumber Trellis with one of the smaller varieties of pumpkin.
When to Plant
On the seed packet, you'll find the number of days to maturity, which will help you select a variety that has time to grow and ripen during your growing season. For instance, if the variety you're considering needs 110 days to mature, make sure you have enough time between your average first and last frost dates. Like tomatoes and peppers, pumpkins thrive in warm weather, so don't plant outside until the weather has settled and there's no chance of frost.
Pumpkin seeds can be planted outdoors or indoors. Gwenael Engelskirchen, who tests new varieties for High Mowing Seeds, prefers to start them inside — about three weeks before ideal outdoor planting weather arrives. A good way to estimate the indoor planting date: Find out your average last frost date and back up three weeks. "By putting a healthy transplant (instead of a seed) into the ground, you are further along in your growing and have that much more insurance that you'll get a successful crop."
Pumpkin seeds germinate and grow quickly. Start with a 2" to 3" pot, such as a biodegradable pot, which can be transplanted right into the ground. Plant two seeds per pot and snip one of the seedlings when it's clear which one is thriving most. You will also need light. About 12 hours in a south-facing window is ideal. Even better, grow the seedlings under lights or in a greenhouse. The goal is to grow a seedling that's large — but not too large — when it's safe to plant outdoors. A sturdy seedling that's 3 to 3 1/2" tall with two or more sets of "true leaves" is just right. If grown indoors too long — or in too large a pot — the plants will be unwieldy and difficult to transplant.
Be Ready for Beetles and Borers
When it comes to pests, cucumber beetles are the most common. Despite the name, cucumber beetles love pumpkin foliage. Small seedlings cannot survive an attack, so it's best to protect them at transplant time. Engelskirchen recalls a set of pumpkin seedlings that was planted one day and defoliated the next morning.
To prevent problems, she covers the plants with garden fabric at planting time and leaves it in place until the plants start to flower — about three to four weeks. At that point, the fabric should be removed for the season, so pollinators have access to the blossoms.
Squash-vine borers can also be a problem. Learn to watch for the telltale "frass" that indicates the presence of a borer. If borers attack, you can use a box cutter to extract them .
Powdery mildew is a disease that sometimes affects pumpkins, especially in areas that are wet and humid. To avoid problems, "Be strategic," Engelskirchen says. "Choose varieties that are resistant to mildew and plant outdoors as early as you can, depending on weather."
As fruit forms along the vine, you can use supports — to keep fruit off the ground and promote even coloring.
More information on pumpkin pests and diseases: Pumpkin Crop Management, Cornell Cooperative Extension.
A rich source of pumpkin-growing wisdom can be found right in your neighborhood. Make contact with your county cooperative extension service, where there are gardeners who can tell you which varieties are known to perform well in your area — and what pests and diseases to watch for. Many enthusiastic pumpkin growers are happy to give advice. And, if you're up to the challenge of growing a "giant pumpkin," read the article How to Grow a Giant Pumpkin, which covers the basics.
Pumpkins are actually a type of winter squash. Many varieties can send out vines that are 10 to 20 feet long, which can be challenging for a raised-bed garden. One option is to grow them on a trellis, such as the Cucumber Trellis. Use a mesh bag or fabric to help support especially heavy fruit. Another technique is to plant them on an outside corner of your raised bed and let the vines ramble onto the grass.
Like summer squash, winter squash need rich soil that's been amended with compost. They need warm weather and warm soil to grow and produce well. In most cases, it takes 90 to 100 days from planting seeds until the squash are ripe. Cold-climate gardeners may want to get an early start by planting seeds indoors about three weeks before the last spring frost. Plant two seeds per 3" pot, and cut off one if both grow.
Transplant into the garden a week or two after the last spring frost. You can warm the soil by covering it with clear plastic, which works better than the traditional black plastic, as long as you seal the edges with soil to contain the heat.
Some winter squash and pumpkins — the bigger ones, generally — will only produce a couple of fruit per plant. The seed catalog or seed packet should tell you what to expect. Pumpkins are always fun for kids, but not always good for pie. If you want jack-o-lanterns, you can grow any variety; for pies and soups, look for "pie pumpkins" or "sugar pumpkins," which have sweeter, more flavorful flesh.
Butternut squash is a high-yielding winter squash and almost the entire fruit is edible. Most other types of squash and pumpkins have thick skins, large interior cavities and lots of seeds. Delicata squash are tasty and just the right for two servings. Buttercup and acorn squash produce medium-sized fruits and are good for storage, as are most winter squashes. Hubbard squash are great for soup, but often get to be 15 to 20 pounds, which can be too much of a good thing.
Harvest your pumpkins and winter squash in the fall, before they can be damaged by frost. Before being stored away, they should be cured in a warm, dry place for several weeks to allow their skin to toughen. Most squash and pumpkins taste better after they've been cured and then stored for a couple weeks, than they do straight from the garden.
Store pumpkins and winter squash in a cool, dry indoor room. A temperature of about 60 degrees F. is ideal so some people store them under the bed in an unused bedroom. Winter squash will rot quickly in the cool and humid conditions of a cellar or garage.
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