How to Fertilize Pumpkins for Maximum Success
Pumpkins are heavy feeders. GardenZeus recommends testing your soil to determine nutrient levels prior to applying fertilizer.
Work compost, composted manures, or well-rotted organic matter into soils before planting, and maintain nutrient-rich surface dressings under mulch. Bury plugs of finished compost or worm compost a few inches outside of the driplines of established pumpkin plants 2 or 3 times per growing season and water thoroughly. For soils low in calcium, crush or grind up eggshells and add to the soil surface under mulch at the base of each plant. Grow pumpkins or other cucurbits only once every 2 to 4 years in a given bed or garden area to allow the soil to recover between plantings.
This photo shows crushed eggshells, ready to be applied to the soil.
GardenZeus recommends adding nitrogen in the form of diluted urea or a cup of chicken manure diluted in 4 gallons of water (half cup if fresh manure) and mixed thoroughly, after seedlings are a few to several inches tall and about once or twice per month thereafter. Adding too much nitrogen may result in rapid growth and lush, high-carbohydrate leaves that attract insect infestation; and slowed or reduced yields.
In hot-summer areas, reduce or discontinue fertilizing with nitrogen by late spring or early summer to avoid producing large, lush leaves that will tend to wilt and cause stress to squash plants during summer heat.
Fish emulsion or seaweed extracts applied as drenches or foliar spray may be beneficial in soils that are infertile, alkaline, or lacking micronutrients.
To view customized information for growing pumpkin in your area, go to GardenZeus and enter your zip code, then go to pumpkin.
Other articles of interest:
Growing Winter Squash and Pumpkins in the California Home Garden
Grow Cucurbits in a Mature Compost Pile
Pumpkins and Companion Planting