By Steve Cramer, Colorado State University Cooperative Extension, Horticulture
If you want to harvest pumpkins by Halloween, late May or early June is the time to plant pumpkin seeds.
Pumpkins are warm-season vegetables that do well in low humidity and usually grow in any soil of average fertility. They won't, however, tolerate wet, poorly aerated soils. Pumpkins need a lot of room and full sun to grow, so plant them at the edge of the garden and allow them to spread on uncultivated ground.
Plant pumpkins in rows 4 to 6 feet apart. Place two seeds in each hole; holes should be about 2 feet apart. Because pumpkins need moderate fertilization, add nitrogen while preparing the soil for planting. When plants have 3 or 4 leaves, thin to 1 plant every 2 feet. Keep weeds under control and scout regularly for insects.
Pumpkins are deep-rooted, water-conserving plants that should be watered deeply and infrequently to encourage good vine and root growth. It's especially important to keep plants watered in late July and early August, when they bloom and set fruit. Pumpkins are ready for harvest when the rind (skin) has toughened and the stems are dry.
For giant-sized pumpkins that can weigh up to several hundred pounds, try growing the Prizewinner variety. For jack-o-lanterns up to 25 pounds, plant Howden; for tall and slender pumpkins, plant Tallman. Baby Bear is a decorative and sweet variety good for cooking. Its nearly hulless seeds are great for toasted snacks and its size makes it perfect for children to carve.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010