How long do cucumber seeds take to germinate?
Cucumber seeds sprout in 3-13 days at an optimal soil temperature of 60-95 °F. Use the planner to estimate days and a sprout date for your soil temperature.
Quick answer
Germination planner
The marker shows your soil temperature; the curve is Oregon State University Extension.
Notes & troubleshooting
A very warm-season crop and one of the fastest germinators in warm soil — about 3 days at 86-95 F, but roughly 13 days at 59 F, with little germination below ~60 F. Direct-sow once soil reaches ~60-70 F, or start indoors 3-4 weeks before transplanting.
If they will not sprout
- Too cold: below 60 F soil, germination stalls and seeds rot — wait for warm soil.
- Damping off: keep media warm and not waterlogged.
- Transplant shock: cucumbers dislike root disturbance; use cells or soil blocks.
Sources & how the planner works
The germination range (60-105 °F), optimal band (60-95 °F, best ~95 °F), 3-13 days to germinate, and 1/2 in sowing depth are taken from the sources below and last reviewed 2026-06-18.
Data basis: Oregon State University Extension — J.F. Harrington soil-temperature germination table (days at 1/2 in depth).
For vegetables the planner reads Oregon State University Extension's measured days-to-seedling at the nearest tested soil temperature (the Harrington table, at 1/2 in planting depth) — it is a direct lookup of published data, not a prediction. For flowers, which have a published optimum range and days but no full temperature curve, the planner shows the cited day range within the optimum band and flags soil that is too cold or too hot. The 'sow date -> sprout window' is the sow date plus the day range. It is general guidance, not a zone-based planting calendar.
General seed-starting guidance only. Soil temperature (not air temperature) drives germination; use a soil thermometer for best results. The OSU/Harrington vegetable data assumes nighttime fluctuation to 60 F or lower and a 1/2 in planting depth. Verify timing for your specific variety and region; extension services publish local recommendations.