When to Plant Cucumbers

Planting time for cucumbers is set by your frost dates, not by the calendar month. Start seeds indoors about 3 weeks before your last spring frost, then transplant about 2 weeks after it. From there it takes roughly 60 days to the first harvest. Cucumbers is a tender crop, and a single light frost ends it, so both ends of its season are hard boundaries. Pick your zone below for exact dates, or find your zone by ZIP if you are not sure which one you are in.

A second sowing in midsummer usually dodges the worst of the cucumber beetle and powdery mildew pressure that kills the spring planting. Because it is a tender crop, the fall sowing has to finish before the first frost with no margin for error, so the sow-by dates in the table above are hard deadlines rather than suggestions.

Fall dates are counted backward from your first frost, not forward from a sowing date. Take the 60 days cucumbers needs, add about two weeks because growth slows once days shorten after the equinox, then add two more weeks of margin because frost kills it outright. That is 88 days before your first frost. The coldest zone where this still works on the averages is Zone 4b.

For the whole-garden version of this arithmetic, see the fall planting calendar by zone, and how to read and stretch your first frost date.

Cucumbers grow well next to corn, beans (bush), radishes and sunflowers. Keep them away from potatoes. Both sprawl and compete hard for ground space; gardeners have long linked the pairing to more blight, though that part is folklore. The full grid for all 24 crops is in the companion planting chart.