Ideal pH: 6.0-6.8. These big plants need lots of food. Choose a sunny spot with fertile, well-draining soil. Dig in a generous quantity of finished compost and/or composted manure. Dig in 1 cup of complete organic fertilizer under each plant. All pumpkins grow male flowers first, then the female flowers are produced. The female flowers have tiny fruits at the base of the petals and require pollination by bees, mostly. Incomplete pollination is common at the beginning of the season, and results in small fruits that are misshapen at the flower end. Discard these damaged fruits before they rot.
For the largest pumpkins, feed weekly throughout the growing season with fish or kelp based fertilizer. Keep the huge plants well watered, particularly in hot weather. Always water the soil, and avoid any form of overhead watering other than rain. Fruit will grow larger if you keep only one fruit per vine. As the fruit develops, try to gently encourage it to grow at a 90° angle to the vine itself. The largest pumpkin varieties will grow on their sides.