Last spring frostMay 7
Start seeds indoorsMar 26
Transplant outMay 21
First harvestJul 20
Last harvestSep 28
First fall frostOct 13
Why these dates work in zone 4a
Zone 4a's last spring frost averages May 7 and first fall frost Oct 13 — about 159 frost-free days. Tomato is frost-sensitive, so the 2w after frost timing builds in a safety margin against a late cold snap — setting plants out too early risks losing them to frost. Starting seeds indoors 6 weeks ahead gives strong transplants ready the moment the soil warms.
Common questions
How long does tomato take to grow in zone 4a?
Tomato matures in about 60–85 days from transplanting. In zone 4a that means setting plants out around May 21 and first picking around Jul 20.
Will tomato survive frost in zone 4a?
No — tomato is frost-sensitive. In zone 4a, wait until after the last frost (around May 7) to plant, and harvest before the first fall frost (around Oct 13).
For soil, spacing, pests and companion planting, see the full tomato growing guide →