Planting and Thinning
Planting dates in Utah vary depending local climate conditions. Planting often begins in early to midApril in southern Utah and may be as late as midJune in cooler areas of northern Utah. Planting is recommended after danger of frost has passed. Local freeze dates can be accessed through the Utah Climate Center (climate.usurf.usu.edu). Cucurbit seeds germinate poorly in cool soils (below 60 °F) and germination is most rapid around 90-95 °F. The cucurbits grow best when temperatures during the day are 75-85 °F and when night temperatures stay above 60 °F. Temperatures above 95 °F slows plant growth, may increase flower abortion, or influence fruit set and fruit sizing.
Plant and row spacings vary with cultivar grown, plant growth habit (bush/vine types), available equipment, irrigation approach, and market requirements. Typically, in-row plant spacing ranges from 12-18 inches apart for cucumbers in irrigated plantings. Summer squash are often planted 24-30 inches apart while winter squash are planted 30-48 inches apart. Pumpkin spacing in row is commonly 36-60 inches apart depending on vining habit and expected fruit size. Typical row spacings vary from 3 to 10 feet apart. Cucumbers and summer squash are planted at the closer row spacings while winter squash and pumpkin rows are wider apart. Higher yields occur with closer spacings but the grower will need to adjust nutrient or water management and fruit size may be smaller when plant densities increase.
Cucumber seeds are commonly planted at ½ to ¾ inches deep (depending on soil moisture, time of year, and irrigation availability) and require 3-5 pounds of seed per acre. Summer squash (bush types) are commonly seeded at 4-6 pounds of seed per acre and sown ¾ to 1½ inches deep (depending on seed size). Winter squash and pumpkins are seeded at 2-4 pounds of seed per acre at a depth of ¾ to 1½ inches. Hybrid seed is more expensive therefore, reduce seeding rates by modifying planters to only plant one seed at the desired in-row spacing. Once seedlings have emerged and have 1-2 leaves, thin stands back to the desired in-row spacing.