Last spring frostMay 6
Transplant outApr 22
First harvestOct 22
Last harvestOct 22
First fall frostOct 22
Why these dates work in zone 3b
Zone 3b's last spring frost averages May 6 and first fall frost Oct 22 — about 169 frost-free days. Rhubarb tolerates light frost, so you can set plants out ahead of the last-frost date and keep harvesting into the cooler fall.
Common questions
How long does rhubarb take to grow in zone 3b?
Rhubarb matures in about 548–730 days from transplanting. In zone 3b that means setting plants out around Apr 22 and first picking around Oct 22.
Will rhubarb survive frost in zone 3b?
Yes — rhubarb tolerates light frost. In zone 3b you can set plants out a little before the last frost (around May 6) and keep harvesting past the first fall frost (around Oct 22).
For soil, spacing, pests and companion planting, see the full rhubarb growing guide →