Pumpkins do best when the seeds are directly planted in the ground. However, if your growing season is very short, seed indoors in peat pots about 2 to 4 weeks before last spring frost. Be sure to harden off before transplanting.
The soil must be thoroughly warmed. Minimum soil temperature for germination is 70ºF. Optimum soil temperature is 95ºF. Pumpkins are very sensitive to the cold.
Pick a site with full sun (to light shade).
Pumpkins are big greedy feeders. They prefer very rich soil that is well-drained and not too soggy. Mix lots of compost and aged mature into the planting site before you sow seeds or tranplant.
Select a site with lots of space for the sprawling vines. 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.
You plant seeds in rows or "pumpkin hills" which are the size of small pitcher mounds. With hills, the soil will warm more quickly and the seeds will germinate faster. This also helps with drainage and pest control.
Prepare the hills in advance with an abundance of old manure dug deep into the ground (12 to 15 inches). If you don't have manure, loosen the soil and mix in a 2- to 4-inch layer of compost
Plant the seeds 1 inch deep into the hills (4 to 5 seeds per hill). Space hills 4 to 8 feet apart.
When the plants are 2 to 3 inches tall, thin to 2 to 3 plants per hill by snipping off unwanted plants without disturbing the roots of the remaining ones.
In rows, sow seeds 6 to 12 inches apart in rows 6 to 10 feet apart. Snip off plants to thin to one plant every 18 to 36 inches.