How to Grow Butternut Pumpkins

Prepare the area to plant your butternut pumpkins. Butternut pumpkins grow very large fruits from 18 inches to up to 36 inches for some varieties, on long vines that can tangle. Plant them in full sun, in open beds or in the front of existing beds to avoid them tangling with other plants in your garden.

Prepare the soil by adding compost and sand, if necessary, to your soil. Butternut pumpkins require sandy soil. If your soil is not sandy, add a small bag of sand and mix with your soil.

Plant the seeds in early summer. Dig a small hole using a hand shovel, and plant the seeds one inch deep and 18 or more inches apart, depending on the variety. Cover the seeds lightly with soil. Alternatively, start the seeds indoors and replant outdoors in early summer. The seeds will germinate within about 10 days.

Add a layer of mulch to the soil once the seeds have germinated to help retain moisture.

Water the plants often to keep the soil evenly moist.

Fertilize the plants every three weeks using an all-purpose vegetable fertilizer.

Check the vines for signs of pests. Butternut pumpkins are prone to pickleworm infestations. If you see pickleworms on the vines, wear garden gloves and remove the pests from the vines. Keeping the soil at a consistent, warm temperature will help to keep pests away, so add a covering of dark landscape fabric over the soil to keep it consistently warm.

Harvest the fruits from the vines in late summer or early fall. The fruits will be ready for harvesting in approximately 75 to 100 days. You can pick the pumpkins when the skin of the fruit turns hard and are a light brown color. Cut the fruits from the vine with a pair of pruning shears, leaving an inch or two of stem attached.