Pumpkin

Adapted from https://www.almanac.com/plant/pumpkins

There are two requirements to growing pumpkins: having the space to grow them and a long growing season (generally, from 75 to 100 frost-free days).

Pumpkins require a lot of nourishment; they are heavy feeders. That said, if you feed and water them as directed, pumpkins are easy to maintain.

PLANTING

Pick a spot with full sun (to light shade) and good soil that drains well (and doesn’t get soggy). Sandy soils high in organic matter are best; if the soil is heavy clay, it might help to add sand and organic matter such as compost, aged manure, or green crops plowed under.

Pumpkins also need space for sprawling vines to run: 50 to 100 square feet per hill. If space is limited, plant at the edge of the garden and direct vines across the lawn; vines will be bothersome for only a few weeks. Vine varieties need 50 to 100 square feet per hill. However, if your garden space is limited, no worries! Plant pumpkins at the edge of the garden and direct vine growth across the lawn or sidewalk. The vines will only be bothersome for a few weeks. You can also grow pumpkins in big 5 to 10 gallon buckets! Or, try miniature varieties.

Preparing Soil for Pumpkins

Pumpkins are big, greedy feeders. At least two weeks before you plan, mix lots of compost or aged manure into the soil at the planting site.

Strongly acid soils will need to be limed. If your soil test finds that your soil pH is too lower, add the recommended amounts of lime.

When to Plant Pumpkins

Pumpkins are very sensitive to the cold. They should not be planted until frost is past and the soil is between 65° and 95°F, the optimal temperature range. For cooler climates, this is often in late May but for warmer climates, you can often wait until late July. Our Planting Calendar shows you the FIRST planting date for your location.

Pumpkins have extensive root systems and respond to an application of 3 to 4 pounds of 10-10-10 fertilizer per 100 square feet. Fertilizer should be broadcast evenly and worked into the top two to 8cm of soil prior to seeding.

How to Plant Pumpkins

Pumpkin seeds are usually sown directly into the soil. Where the growing season is very short, sow indoors in peat pots, 2 to 4 weeks before last spring frost. Harden off seedlings before transplanting into warm, aged manure/compost-enriched soil.

There are two ways pumpkin seeds are usually planted: rows or hills. Note: A hill does not mean the soil has to be mounded; it’s a spot containing a group of plants or seeds. Hills warm soil quickly (so seeds germinate faster) and aid with drainage and pest control. Prepare hills by digging down 12 to 40cm and mixing/filling in with lots of aged manure and/or compost.

For rows: Sow seeds about 15-30cm apart in rows that are 6 to 10 feet apart. Once the seedlings grow, thin to one plant every 40 to 80 cm.

For hills: Plant 4 to 8 feet apart. The soil at each hill may be mounded or left level with the rest of the area. Set seeds 2cm deep with 4 or 5 seeds per hill. Keep seeds moist until germination. When the plants are 5-8cm tall, thin to 2 to 3 plants per hill by snipping off unwanted plants without disturbing the roots of the remaining ones.

How to Grow Pumpkins

Use row covers to protect plants early in the season and to prevent insect problems. However, remember to remove covers before flowering to allow pollination by insects!

Pumpkins are very thirsty plants and need lots of water. Water deeply, especially during fruit set.

When watering: Try to keep foliage and fruit dry unless it’s a sunny day. Dampness will make rot and other diseases more likely.

Add mulch around your pumpkins to keep in moisture, suppress weeds, and discourage pests.

Remember that pumpkins are tender from planting to harvest. Control weeds with mulch. Do not overcultivate, or their very shallow roots may be damaged.

Most small vine varieties can be trained up a trellis.

Larger varieties can be trained upward on a trellis, too—though it is an engineering challenge to support the fruit—usually with netting or old stockings.

If your first flowers aren’t forming fruits, that’s normal. Both male and female blossoms need to open. Be patient.

Bees are essential for pollination, so be mindful when using insecticides to kill pests. If you must use, apply only in the late afternoon or early evening, when blossoms are closed for the day. To attract more bees, try placing a bee house in your garden.

Pumpkin vines, though obstinate, are very delicate. Take care not to damage vines, as this can reduce the quality of fruit.

Fertilising

Pumpkins are HEAVY feeders. Regular treatments of manure or compost mixed with water will sustain good growth.

Fertilize on a regular basis. Use a high nitrogen formula in early plant growth. Fertilize when plants are about one foot tall, just before vines begin to run. Switch over to a fertilizer high in phosphorous just before the blooming period.

Pinch off the fuzzy ends of each vine after a few pumpkins have formed. This will stop vine growth so that the plant’s energies are focused on the fruit.

Pruning the vines may help with space, as well as allow the plant’s energy to be concentrated on the remaining vines and fruit.

Gardeners who are looking for a “prize for size” pumpkin might select the two or three prime candidates and remove all other fruit and vines.

As the fruit develops, they should be turned (with great care not to hurt the vine or stem) to encourage an even shape.

Place a thin board or heavy cardboard under ripening melons and pumpkins to avoid decay and insect damage.

Spacing for Pumpkins

PESTS/DISEASES

Squash bugs and cucumber beetles are common, especially later in summer. Contact your local Cooperative Extension for potential controls.

Aphids

Squash Vine Borer

Powdery Mildew

Anthracnose

Poor light, too much fertilizer, poor weather at bloom time, and reduced pollinating insect activity can negatively impact fruit set.

How to Harvest Pumpkins

Your best bet is to harvest pumpkins when they are fully mature. They will keep best this way. Do not pick pumpkins off the vine because they have reached your desired size. If you want small pumpkins, buy a small variety instead!

A pumpkin is ripe when its skin turns a deep, solid color (orange for most varieties).

When you thump the pumpkin with a finger, the rind will feel hard and it will sound hollow. Press your nail into the pumpkin’s skin; if it resists puncture, it is ripe.

Harvest pumpkins and winter squashes on a dry day after the plants have died back and the skins are hard.

To slow decay, leave 2-5cm of stem on pumpkins and winter squash when harvesting them.

To harvest the pumpkin, cut the fruit off the vine carefully with a sharp knife or pruners; do not tear. Be sure not to cut too close to the pumpkin; a liberal amount of stem (8-12cm) will increase the pumpkin’s keeping time.

Handle pumpkins very gently or they may bruise.

How to Cure, Store, and Display Pumpkins

Pumpkins should be cured in the sun for about 10 to 14 days to harden properly. This is a great time to display your pumpkin on the front porch! If you’re carving a pumpkin, carve no more than three days before Halloween or the pumpkin will begin to rot.

Store pumpkins (after curing) in a cool, dry bedroom, cellar, or root cellar—anywhere around 55ºF