To plant cucumbers, the spacing depends on whether you are growing them on the ground or vertically on a trellis, as well as whether you are planting seeds or transplants:

• For cucumbers grown on the ground :
  • If planting seeds directly in rows, space seeds about 10-12 inches apart with rows 18-24 inches apart.
  • If planting in groups, space groups about 18 inches apart in all directions.
  • When planting transplants, space plants about 36 to 60 inches (3 to 5 feet) apart to allow room for sprawling vines.
  • Other sources recommend spacing about 90 to 100 cm (35 to 40 inches) apart for sprawling plants

• For cucumbers grown vertically on a trellis :
  • Seeds can be planted closer, about 4 to 6 inches apart at the base of the trellis.
  • Transplants should be spaced 6 to 8 inches apart.
  • Some guidelines suggest about 12 inches (30 cm) apart for trellis-grown plants.
  • Vertical growing allows closer spacing due to better air circulation and less ground space needed

• For bush varieties or container growing :
  • Plant one bush cucumber per 2 to 3 gallons of soil.
  • Standard vining cucumbers in containers need about 5 gallons of soil per plant

In summary, for traditional ground planting, cucumbers should be spaced about 3 to 5 feet apart, while for trellised cucumbers, spacing can be as close as 6 to 12 inches apart. This spacing helps ensure good air circulation, reduces disease risk, and allows plants enough room to grow and produce well