Whether you grow just one or an entire patch, the timing and preparation for planting pumpkins is key to growing this warm-season annual. Pumpkins are sensitive to frost. The seeds need warm temperatures with no threat of frost for 90 days or more, depending on the variety and desired size. Allowing enough growing room and providing ideal growing conditions produces quality pumpkins in your garden.
The general time required for pumpkins to reach maturity is between 90 and 120 days. When planning the timing of your planting, determine the growth time needed for the specific variety you choose. If you want to harvest the pumpkins in October, count back the number of days needed to reach maturity to get an estimated planting time. You should wait at least two weeks after the last usual frost of the spring so the growing plants aren't damaged. Soil temperatures of at least 65 F allow the seeds to germinate well.
Pumpkins need a large space to accommodate all of the vine growth and the large size of the fruit as they grow. Pumpkins are typically grown in large hills that allow the vines to grow down and prevent the crown from rotting. The mounds are spaced at least 6 feet apart. Choose a planting location with enough space to accommodate the number of pumpkin plants you want to grow. Your pumpkins will grow best in full sun with well-draining soil.
Pumpkins like soil that is loose and fertile. Adding organic matter, such as compost, improves the structure and nutrients in the soil. Hills for planting pumpkin seeds are usually at least 8 inches high and between 12 and 18 inches in diameter. Form the mounds for the number of plants you want to grow. If you plan to use trellises to support the vine growth of the pumpkins, it's best to install them before planting the pumpkins so you don't damage the roots with the trellis supports.
Each hill should have one or two plants growing on it, but starting with six seeds allows you to choose the strongest seedlings. Leave at least 3 inches between the pumpkin seeds on the hill. The seeds need 1 inch of soil on top of them at planting. Water the seeds after planting. The soil should stay moist but not soggy while the seedlings grow. Once the plants emerge and grow at least four true leaves, you can thin them to the best one or two plants on each hill by cutting off the others at the base.
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